Series comparison

-[PULL 0/2] Net patches
+[PULL V2 00/15] Net patches
-The following changes since commit d1fe59377bbbf91dfded1f08ffe3c636e9db8dc0:
+The following changes since commit d9ccf33f9479201e5add8db0af68ca9ca8da358b:
-  Merge remote-tracking branch 'remotes/vivier2/tags/trivial-branch-for-6.2-pull-request' into staging (2021-09-16 16:02:31 +0100)
+  Merge remote-tracking branch 'remotes/lvivier-gitlab/tags/linux-user-for-7.0-pull-request' into staging (2022-03-09 20:01:17 +0000)
 are available in the git repository at:
   https://github.com/jasowang/qemu.git tags/net-pull-request
-for you to fetch changes up to bedd7e93d01961fcb16a97ae45d93acf357e11f6:
+for you to fetch changes up to eea40402ecf895ed345f8e8eb07dbb484f4542c5:
-  virtio-net: fix use after unmap/free for sg (2021-09-17 16:07:52 +0800)
+  vdpa: Expose VHOST_F_LOG_ALL on SVQ (2022-03-10 10:26:32 +0800)
 ----------------------------------------------------------------
 ----------------------------------------------------------------
+Eugenio Pérez (14):
+      vhost: Add VhostShadowVirtqueue
+      vhost: Add Shadow VirtQueue kick forwarding capabilities
+      vhost: Add Shadow VirtQueue call forwarding capabilities
+      vhost: Add vhost_svq_valid_features to shadow vq
+      virtio: Add vhost_svq_get_vring_addr
+      vdpa: adapt vhost_ops callbacks to svq
+      vhost: Shadow virtqueue buffers forwarding
+      util: Add iova_tree_alloc_map
+      util: add iova_tree_find_iova
+      vhost: Add VhostIOVATree
+      vdpa: Add custom IOTLB translations to SVQ
+      vdpa: Adapt vhost_vdpa_get_vring_base to SVQ
+      vdpa: Never set log_base addr if SVQ is enabled
+      vdpa: Expose VHOST_F_LOG_ALL on SVQ
 Jason Wang (1):
-      virtio-net: fix use after unmap/free for sg
+      virtio-net: fix map leaking on error during receive
-Paolo Bonzini (1):
+ hw/net/virtio-net.c                |   1 +
-      ebpf: only include in system emulators
+ hw/virtio/meson.build              |   2 +-
+ hw/virtio/vhost-iova-tree.c        | 110 +++++++
- ebpf/meson.build    |  2 +-
+ hw/virtio/vhost-iova-tree.h        |  27 ++
- hw/net/virtio-net.c | 39 ++++++++++++++++++++++++++++++++-------
+ hw/virtio/vhost-shadow-virtqueue.c | 638 +++++++++++++++++++++++++++++++++++++
-files changed, 33 insertions(+), 8 deletions(-)
+ hw/virtio/vhost-shadow-virtqueue.h |  87 +++++
  hw/virtio/vhost-vdpa.c             | 525 +++++++++++++++++++++++++++++-
  include/hw/virtio/vhost-vdpa.h     |   8 +
  include/qemu/iova-tree.h           |  38 ++-
  util/iova-tree.c                   | 169 ++++++++++
 files changed, 1588 insertions(+), 17 deletions(-)
  create mode 100644 hw/virtio/vhost-iova-tree.c
  create mode 100644 hw/virtio/vhost-iova-tree.h
  create mode 100644 hw/virtio/vhost-shadow-virtqueue.c
  create mode 100644 hw/virtio/vhost-shadow-virtqueue.h

-New patch
+[PULL V2 01/15] virtio-net: fix map leaking on error during receive
+Commit bedd7e93d0196 ("virtio-net: fix use after unmap/free for sg")
+tries to fix the use after free of the sg by caching the virtqueue
+elements in an array and unmap them at once after receiving the
+packets, But it forgot to unmap the cached elements on error which
+will lead to leaking of mapping and other unexpected results.
+Fixing this by detaching the cached elements on error. This addresses
+CVE-2022-26353.
+Reported-by: Victor Tom <vv474172261@gmail.com>
+Cc: qemu-stable@nongnu.org
+Fixes: CVE-2022-26353
+Fixes: bedd7e93d0196 ("virtio-net: fix use after unmap/free for sg")
+Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+---
+ hw/net/virtio-net.c | 1 +
+file changed, 1 insertion(+)
+diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/net/virtio-net.c
++++ b/hw/net/virtio-net.c
+@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
+ err:
+     for (j = 0; j < i; j++) {
++        virtqueue_detach_element(q->rx_vq, elems[j], lens[j]);
+         g_free(elems[j]);
+     }
+--
+.7.4

-New patch
+[PULL V2 02/15] vhost: Add VhostShadowVirtqueue
+From: Eugenio Pérez <eperezma@redhat.com>
+Vhost shadow virtqueue (SVQ) is an intermediate jump for virtqueue
+notifications and buffers, allowing qemu to track them. While qemu is
+forwarding the buffers and virtqueue changes, it is able to commit the
+memory it's being dirtied, the same way regular qemu's VirtIO devices
+do.
+This commit only exposes basic SVQ allocation and free. Next patches of
+the series add functionality like notifications and buffers forwarding.
+Acked-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+---
+ hw/virtio/meson.build              |  2 +-
+ hw/virtio/vhost-shadow-virtqueue.c | 62 ++++++++++++++++++++++++++++++++++++++
+ hw/virtio/vhost-shadow-virtqueue.h | 28 +++++++++++++++++
+files changed, 91 insertions(+), 1 deletion(-)
+ create mode 100644 hw/virtio/vhost-shadow-virtqueue.c
+ create mode 100644 hw/virtio/vhost-shadow-virtqueue.h
+diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/virtio/meson.build
++++ b/hw/virtio/meson.build
+@@ -XXX,XX +XXX,XX @@ softmmu_ss.add(when: 'CONFIG_ALL', if_true: files('vhost-stub.c'))
+ virtio_ss = ss.source_set()
+ virtio_ss.add(files('virtio.c'))
+-virtio_ss.add(when: 'CONFIG_VHOST', if_true: files('vhost.c', 'vhost-backend.c'))
++virtio_ss.add(when: 'CONFIG_VHOST', if_true: files('vhost.c', 'vhost-backend.c', 'vhost-shadow-virtqueue.c'))
+ virtio_ss.add(when: 'CONFIG_VHOST_USER', if_true: files('vhost-user.c'))
+ virtio_ss.add(when: 'CONFIG_VHOST_VDPA', if_true: files('vhost-vdpa.c'))
+ virtio_ss.add(when: 'CONFIG_VIRTIO_BALLOON', if_true: files('virtio-balloon.c'))
+diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
+new file mode 100644
+index XXXXXXX..XXXXXXX
+--- /dev/null
++++ b/hw/virtio/vhost-shadow-virtqueue.c
+@@ -XXX,XX +XXX,XX @@
++/*
++ * vhost shadow virtqueue
++ *
++ * SPDX-FileCopyrightText: Red Hat, Inc. 2021
++ * SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
++ *
++ * SPDX-License-Identifier: GPL-2.0-or-later
++ */
++
++#include "qemu/osdep.h"
++#include "hw/virtio/vhost-shadow-virtqueue.h"
++
++#include "qemu/error-report.h"
++
++/**
++ * Creates vhost shadow virtqueue, and instructs the vhost device to use the
++ * shadow methods and file descriptors.
++ *
++ * Returns the new virtqueue or NULL.
++ *
++ * In case of error, reason is reported through error_report.
++ */
++VhostShadowVirtqueue *vhost_svq_new(void)
++{
++    g_autofree VhostShadowVirtqueue *svq = g_new0(VhostShadowVirtqueue, 1);
++    int r;
++
++    r = event_notifier_init(&svq->hdev_kick, 0);
++    if (r != 0) {
++        error_report("Couldn't create kick event notifier: %s (%d)",
++                     g_strerror(errno), errno);
++        goto err_init_hdev_kick;
++    }
++
++    r = event_notifier_init(&svq->hdev_call, 0);
++    if (r != 0) {
++        error_report("Couldn't create call event notifier: %s (%d)",
++                     g_strerror(errno), errno);
++        goto err_init_hdev_call;
++    }
++
++    return g_steal_pointer(&svq);
++
++err_init_hdev_call:
++    event_notifier_cleanup(&svq->hdev_kick);
++
++err_init_hdev_kick:
++    return NULL;
++}
++
++/**
++ * Free the resources of the shadow virtqueue.
++ *
++ * @pvq: gpointer to SVQ so it can be used by autofree functions.
++ */
++void vhost_svq_free(gpointer pvq)
++{
++    VhostShadowVirtqueue *vq = pvq;
++    event_notifier_cleanup(&vq->hdev_kick);
++    event_notifier_cleanup(&vq->hdev_call);
++    g_free(vq);
++}
+diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
+new file mode 100644
+index XXXXXXX..XXXXXXX
+--- /dev/null
++++ b/hw/virtio/vhost-shadow-virtqueue.h
+@@ -XXX,XX +XXX,XX @@
++/*
++ * vhost shadow virtqueue
++ *
++ * SPDX-FileCopyrightText: Red Hat, Inc. 2021
++ * SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
++ *
++ * SPDX-License-Identifier: GPL-2.0-or-later
++ */
++
++#ifndef VHOST_SHADOW_VIRTQUEUE_H
++#define VHOST_SHADOW_VIRTQUEUE_H
++
++#include "qemu/event_notifier.h"
++
++/* Shadow virtqueue to relay notifications */
++typedef struct VhostShadowVirtqueue {
++    /* Shadow kick notifier, sent to vhost */
++    EventNotifier hdev_kick;
++    /* Shadow call notifier, sent to vhost */
++    EventNotifier hdev_call;
++} VhostShadowVirtqueue;
++
++VhostShadowVirtqueue *vhost_svq_new(void);
++
++void vhost_svq_free(gpointer vq);
++G_DEFINE_AUTOPTR_CLEANUP_FUNC(VhostShadowVirtqueue, vhost_svq_free);
++
++#endif
+--
+.7.4

-New patch
+[PULL V2 03/15] vhost: Add Shadow VirtQueue kick forwarding capabilities
+From: Eugenio Pérez <eperezma@redhat.com>
 At this mode no buffer forwarding will be performed in SVQ mode: Qemu
 will just forward the guest's kicks to the device.
 Host memory notifiers regions are left out for simplicity, and they will
 not be addressed in this series.
 Acked-by: Michael S. Tsirkin <mst@redhat.com>
 Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
 Signed-off-by: Jason Wang <jasowang@redhat.com>
 ---
  hw/virtio/vhost-shadow-virtqueue.c |  56 ++++++++++++++
  hw/virtio/vhost-shadow-virtqueue.h |  14 ++++
  hw/virtio/vhost-vdpa.c             | 145 ++++++++++++++++++++++++++++++++++++-
  include/hw/virtio/vhost-vdpa.h     |   4 +
 files changed, 217 insertions(+), 2 deletions(-)
 diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/virtio/vhost-shadow-virtqueue.c
 +++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -XXX,XX +XXX,XX @@
  #include "hw/virtio/vhost-shadow-virtqueue.h"
  #include "qemu/error-report.h"
 +#include "qemu/main-loop.h"
 +#include "linux-headers/linux/vhost.h"
 +
 +/**
 + * Forward guest notifications.
 + *
 + * @n: guest kick event notifier, the one that guest set to notify svq.
 + */
 +static void vhost_handle_guest_kick(EventNotifier *n)
 +{
 +    VhostShadowVirtqueue *svq = container_of(n, VhostShadowVirtqueue,
 +                                             svq_kick);
 +    event_notifier_test_and_clear(n);
 +    event_notifier_set(&svq->hdev_kick);
 +}
 +
 +/**
 + * Set a new file descriptor for the guest to kick the SVQ and notify for avail
 + *
 + * @svq: The svq
 + * @svq_kick_fd: The svq kick fd
 + *
 + * Note that the SVQ will never close the old file descriptor.
 + */
 +void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd)
 +{
 +    EventNotifier *svq_kick = &svq->svq_kick;
 +    bool poll_stop = VHOST_FILE_UNBIND != event_notifier_get_fd(svq_kick);
 +    bool poll_start = svq_kick_fd != VHOST_FILE_UNBIND;
 +
 +    if (poll_stop) {
 +        event_notifier_set_handler(svq_kick, NULL);
 +    }
 +
 +    /*
 +     * event_notifier_set_handler already checks for guest's notifications if
 +     * they arrive at the new file descriptor in the switch, so there is no
 +     * need to explicitly check for them.
 +     */
 +    if (poll_start) {
 +        event_notifier_init_fd(svq_kick, svq_kick_fd);
 +        event_notifier_set(svq_kick);
 +        event_notifier_set_handler(svq_kick, vhost_handle_guest_kick);
 +    }
 +}
 +
 +/**
 + * Stop the shadow virtqueue operation.
 + * @svq: Shadow Virtqueue
 + */
 +void vhost_svq_stop(VhostShadowVirtqueue *svq)
 +{
 +    event_notifier_set_handler(&svq->svq_kick, NULL);
 +}
  /**
   * Creates vhost shadow virtqueue, and instructs the vhost device to use the
@@ -XXX,XX +XXX,XX @@ VhostShadowVirtqueue *vhost_svq_new(void)
          goto err_init_hdev_call;
      }
 +    event_notifier_init_fd(&svq->svq_kick, VHOST_FILE_UNBIND);
      return g_steal_pointer(&svq);
  err_init_hdev_call:
@@ -XXX,XX +XXX,XX @@ err_init_hdev_kick:
  void vhost_svq_free(gpointer pvq)
  {
      VhostShadowVirtqueue *vq = pvq;
 +    vhost_svq_stop(vq);
      event_notifier_cleanup(&vq->hdev_kick);
      event_notifier_cleanup(&vq->hdev_call);
      g_free(vq);
 diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/virtio/vhost-shadow-virtqueue.h
 +++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -XXX,XX +XXX,XX @@ typedef struct VhostShadowVirtqueue {
      EventNotifier hdev_kick;
      /* Shadow call notifier, sent to vhost */
      EventNotifier hdev_call;
 +
 +    /*
 +     * Borrowed virtqueue's guest to host notifier. To borrow it in this event
 +     * notifier allows to recover the VhostShadowVirtqueue from the event loop
 +     * easily. If we use the VirtQueue's one, we don't have an easy way to
 +     * retrieve VhostShadowVirtqueue.
 +     *
 +     * So shadow virtqueue must not clean it, or we would lose VirtQueue one.
 +     */
 +    EventNotifier svq_kick;
  } VhostShadowVirtqueue;
 +void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd);
 +
 +void vhost_svq_stop(VhostShadowVirtqueue *svq);
 +
  VhostShadowVirtqueue *vhost_svq_new(void);
  void vhost_svq_free(gpointer vq);
 diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/virtio/vhost-vdpa.c
 +++ b/hw/virtio/vhost-vdpa.c
@@ -XXX,XX +XXX,XX @@
  #include "hw/virtio/vhost.h"
  #include "hw/virtio/vhost-backend.h"
  #include "hw/virtio/virtio-net.h"
 +#include "hw/virtio/vhost-shadow-virtqueue.h"
  #include "hw/virtio/vhost-vdpa.h"
  #include "exec/address-spaces.h"
  #include "qemu/main-loop.h"
  #include "cpu.h"
  #include "trace.h"
  #include "qemu-common.h"
 +#include "qapi/error.h"
  /*
   * Return one past the end of the end of section. Be careful with uint64_t
@@ -XXX,XX +XXX,XX @@ static bool vhost_vdpa_one_time_request(struct vhost_dev *dev)
      return v->index != 0;
  }
 +static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
 +                               Error **errp)
 +{
 +    g_autoptr(GPtrArray) shadow_vqs = NULL;
 +
 +    if (!v->shadow_vqs_enabled) {
 +        return 0;
 +    }
 +
 +    shadow_vqs = g_ptr_array_new_full(hdev->nvqs, vhost_svq_free);
 +    for (unsigned n = 0; n < hdev->nvqs; ++n) {
 +        g_autoptr(VhostShadowVirtqueue) svq = vhost_svq_new();
 +
 +        if (unlikely(!svq)) {
 +            error_setg(errp, "Cannot create svq %u", n);
 +            return -1;
 +        }
 +        g_ptr_array_add(shadow_vqs, g_steal_pointer(&svq));
 +    }
 +
 +    v->shadow_vqs = g_steal_pointer(&shadow_vqs);
 +    return 0;
 +}
 +
  static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error **errp)
  {
      struct vhost_vdpa *v;
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error **errp)
      dev->opaque =  opaque ;
      v->listener = vhost_vdpa_memory_listener;
      v->msg_type = VHOST_IOTLB_MSG_V2;
 +    ret = vhost_vdpa_init_svq(dev, v, errp);
 +    if (ret) {
 +        goto err;
 +    }
      vhost_vdpa_get_iova_range(v);
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error **errp)
                                 VIRTIO_CONFIG_S_DRIVER);
      return 0;
 +
 +err:
 +    ram_block_discard_disable(false);
 +    return ret;
  }
  static void vhost_vdpa_host_notifier_uninit(struct vhost_dev *dev,
@@ -XXX,XX +XXX,XX @@ static void vhost_vdpa_host_notifiers_uninit(struct vhost_dev *dev, int n)
  static void vhost_vdpa_host_notifiers_init(struct vhost_dev *dev)
  {
 +    struct vhost_vdpa *v = dev->opaque;
      int i;
 +    if (v->shadow_vqs_enabled) {
 +        /* FIXME SVQ is not compatible with host notifiers mr */
 +        return;
 +    }
 +
      for (i = dev->vq_index; i < dev->vq_index + dev->nvqs; i++) {
          if (vhost_vdpa_host_notifier_init(dev, i)) {
              goto err;
@@ -XXX,XX +XXX,XX @@ err:
      return;
  }
 +static void vhost_vdpa_svq_cleanup(struct vhost_dev *dev)
 +{
 +    struct vhost_vdpa *v = dev->opaque;
 +    size_t idx;
 +
 +    if (!v->shadow_vqs) {
 +        return;
 +    }
 +
 +    for (idx = 0; idx < v->shadow_vqs->len; ++idx) {
 +        vhost_svq_stop(g_ptr_array_index(v->shadow_vqs, idx));
 +    }
 +    g_ptr_array_free(v->shadow_vqs, true);
 +}
 +
  static int vhost_vdpa_cleanup(struct vhost_dev *dev)
  {
      struct vhost_vdpa *v;
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_cleanup(struct vhost_dev *dev)
      trace_vhost_vdpa_cleanup(dev, v);
      vhost_vdpa_host_notifiers_uninit(dev, dev->nvqs);
      memory_listener_unregister(&v->listener);
 +    vhost_vdpa_svq_cleanup(dev);
      dev->opaque = NULL;
      ram_block_discard_disable(false);
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_get_device_id(struct vhost_dev *dev,
      return ret;
  }
 +static void vhost_vdpa_reset_svq(struct vhost_vdpa *v)
 +{
 +    if (!v->shadow_vqs_enabled) {
 +        return;
 +    }
 +
 +    for (unsigned i = 0; i < v->shadow_vqs->len; ++i) {
 +        VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, i);
 +        vhost_svq_stop(svq);
 +    }
 +}
 +
  static int vhost_vdpa_reset_device(struct vhost_dev *dev)
  {
 +    struct vhost_vdpa *v = dev->opaque;
      int ret;
      uint8_t status = 0;
 +    vhost_vdpa_reset_svq(v);
 +
      ret = vhost_vdpa_call(dev, VHOST_VDPA_SET_STATUS, &status);
      trace_vhost_vdpa_reset_device(dev, status);
      return ret;
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_get_config(struct vhost_dev *dev, uint8_t *config,
      return ret;
   }
 +static int vhost_vdpa_set_vring_dev_kick(struct vhost_dev *dev,
 +                                         struct vhost_vring_file *file)
 +{
 +    trace_vhost_vdpa_set_vring_kick(dev, file->index, file->fd);
 +    return vhost_vdpa_call(dev, VHOST_SET_VRING_KICK, file);
 +}
 +
 +/**
 + * Set the shadow virtqueue descriptors to the device
 + *
 + * @dev: The vhost device model
 + * @svq: The shadow virtqueue
 + * @idx: The index of the virtqueue in the vhost device
 + * @errp: Error
 + */
 +static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
 +                                 VhostShadowVirtqueue *svq,
 +                                 unsigned idx,
 +                                 Error **errp)
 +{
 +    struct vhost_vring_file file = {
 +        .index = dev->vq_index + idx,
 +    };
 +    const EventNotifier *event_notifier = &svq->hdev_kick;
 +    int r;
 +
 +    file.fd = event_notifier_get_fd(event_notifier);
 +    r = vhost_vdpa_set_vring_dev_kick(dev, &file);
 +    if (unlikely(r != 0)) {
 +        error_setg_errno(errp, -r, "Can't set device kick fd");
 +    }
 +
 +    return r == 0;
 +}
 +
 +static bool vhost_vdpa_svqs_start(struct vhost_dev *dev)
 +{
 +    struct vhost_vdpa *v = dev->opaque;
 +    Error *err = NULL;
 +    unsigned i;
 +
 +    if (!v->shadow_vqs) {
 +        return true;
 +    }
 +
 +    for (i = 0; i < v->shadow_vqs->len; ++i) {
 +        VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, i);
 +        bool ok = vhost_vdpa_svq_setup(dev, svq, i, &err);
 +        if (unlikely(!ok)) {
 +            error_reportf_err(err, "Cannot setup SVQ %u: ", i);
 +            return false;
 +        }
 +    }
 +
 +    return true;
 +}
 +
  static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
  {
      struct vhost_vdpa *v = dev->opaque;
 +    bool ok;
      trace_vhost_vdpa_dev_start(dev, started);
      if (started) {
          vhost_vdpa_host_notifiers_init(dev);
 +        ok = vhost_vdpa_svqs_start(dev);
 +        if (unlikely(!ok)) {
 +            return -1;
 +        }
          vhost_vdpa_set_vring_ready(dev);
      } else {
          vhost_vdpa_host_notifiers_uninit(dev, dev->nvqs);
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_get_vring_base(struct vhost_dev *dev,
  static int vhost_vdpa_set_vring_kick(struct vhost_dev *dev,
                                         struct vhost_vring_file *file)
  {
 -    trace_vhost_vdpa_set_vring_kick(dev, file->index, file->fd);
 -    return vhost_vdpa_call(dev, VHOST_SET_VRING_KICK, file);
 +    struct vhost_vdpa *v = dev->opaque;
 +    int vdpa_idx = file->index - dev->vq_index;
 +
 +    if (v->shadow_vqs_enabled) {
 +        VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, vdpa_idx);
 +        vhost_svq_set_svq_kick_fd(svq, file->fd);
 +        return 0;
 +    } else {
 +        return vhost_vdpa_set_vring_dev_kick(dev, file);
 +    }
  }
  static int vhost_vdpa_set_vring_call(struct vhost_dev *dev,
 diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
 index XXXXXXX..XXXXXXX 100644
 --- a/include/hw/virtio/vhost-vdpa.h
 +++ b/include/hw/virtio/vhost-vdpa.h
@@ -XXX,XX +XXX,XX @@
  #ifndef HW_VIRTIO_VHOST_VDPA_H
  #define HW_VIRTIO_VHOST_VDPA_H
 +#include <gmodule.h>
 +
  #include "hw/virtio/virtio.h"
  #include "standard-headers/linux/vhost_types.h"
@@ -XXX,XX +XXX,XX @@ typedef struct vhost_vdpa {
      bool iotlb_batch_begin_sent;
      MemoryListener listener;
      struct vhost_vdpa_iova_range iova_range;
 +    bool shadow_vqs_enabled;
 +    GPtrArray *shadow_vqs;
      struct vhost_dev *dev;
      VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
  } VhostVDPA;
 --
 .7.4

-New patch
+[PULL V2 04/15] vhost: Add Shadow VirtQueue call forwarding capabilities
+From: Eugenio Pérez <eperezma@redhat.com>
+This will make qemu aware of the device used buffers, allowing it to
+write the guest memory with its contents if needed.
+Acked-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+---
+ hw/virtio/vhost-shadow-virtqueue.c | 38 ++++++++++++++++++++++++++++++++++++++
+ hw/virtio/vhost-shadow-virtqueue.h |  4 ++++
+ hw/virtio/vhost-vdpa.c             | 31 +++++++++++++++++++++++++++++--
+files changed, 71 insertions(+), 2 deletions(-)
+diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/virtio/vhost-shadow-virtqueue.c
++++ b/hw/virtio/vhost-shadow-virtqueue.c
+@@ -XXX,XX +XXX,XX @@ static void vhost_handle_guest_kick(EventNotifier *n)
+ }
+ /**
++ * Forward vhost notifications
++ *
++ * @n: hdev call event notifier, the one that device set to notify svq.
++ */
++static void vhost_svq_handle_call(EventNotifier *n)
++{
++    VhostShadowVirtqueue *svq = container_of(n, VhostShadowVirtqueue,
++                                             hdev_call);
++    event_notifier_test_and_clear(n);
++    event_notifier_set(&svq->svq_call);
++}
++
++/**
++ * Set the call notifier for the SVQ to call the guest
++ *
++ * @svq: Shadow virtqueue
++ * @call_fd: call notifier
++ *
++ * Called on BQL context.
++ */
++void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd)
++{
++    if (call_fd == VHOST_FILE_UNBIND) {
++        /*
++         * Fail event_notifier_set if called handling device call.
++         *
++         * SVQ still needs device notifications, since it needs to keep
++         * forwarding used buffers even with the unbind.
++         */
++        memset(&svq->svq_call, 0, sizeof(svq->svq_call));
++    } else {
++        event_notifier_init_fd(&svq->svq_call, call_fd);
++    }
++}
++
++/**
+  * Set a new file descriptor for the guest to kick the SVQ and notify for avail
+  *
+  * @svq: The svq
+@@ -XXX,XX +XXX,XX @@ VhostShadowVirtqueue *vhost_svq_new(void)
+     }
+     event_notifier_init_fd(&svq->svq_kick, VHOST_FILE_UNBIND);
++    event_notifier_set_handler(&svq->hdev_call, vhost_svq_handle_call);
+     return g_steal_pointer(&svq);
+ err_init_hdev_call:
+@@ -XXX,XX +XXX,XX @@ void vhost_svq_free(gpointer pvq)
+     VhostShadowVirtqueue *vq = pvq;
+     vhost_svq_stop(vq);
+     event_notifier_cleanup(&vq->hdev_kick);
++    event_notifier_set_handler(&vq->hdev_call, NULL);
+     event_notifier_cleanup(&vq->hdev_call);
+     g_free(vq);
+ }
+diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/virtio/vhost-shadow-virtqueue.h
++++ b/hw/virtio/vhost-shadow-virtqueue.h
+@@ -XXX,XX +XXX,XX @@ typedef struct VhostShadowVirtqueue {
+      * So shadow virtqueue must not clean it, or we would lose VirtQueue one.
+      */
+     EventNotifier svq_kick;
++
++    /* Guest's call notifier, where the SVQ calls guest. */
++    EventNotifier svq_call;
+ } VhostShadowVirtqueue;
+ void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd);
++void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd);
+ void vhost_svq_stop(VhostShadowVirtqueue *svq);
+diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/virtio/vhost-vdpa.c
++++ b/hw/virtio/vhost-vdpa.c
+@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_dev_kick(struct vhost_dev *dev,
+     return vhost_vdpa_call(dev, VHOST_SET_VRING_KICK, file);
+ }
++static int vhost_vdpa_set_vring_dev_call(struct vhost_dev *dev,
++                                         struct vhost_vring_file *file)
++{
++    trace_vhost_vdpa_set_vring_call(dev, file->index, file->fd);
++    return vhost_vdpa_call(dev, VHOST_SET_VRING_CALL, file);
++}
++
+ /**
+  * Set the shadow virtqueue descriptors to the device
+  *
+@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_dev_kick(struct vhost_dev *dev,
+  * @svq: The shadow virtqueue
+  * @idx: The index of the virtqueue in the vhost device
+  * @errp: Error
++ *
++ * Note that this function does not rewind kick file descriptor if cannot set
++ * call one.
+  */
+ static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
+                                  VhostShadowVirtqueue *svq,
+@@ -XXX,XX +XXX,XX @@ static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
+     r = vhost_vdpa_set_vring_dev_kick(dev, &file);
+     if (unlikely(r != 0)) {
+         error_setg_errno(errp, -r, "Can't set device kick fd");
++        return false;
++    }
++
++    event_notifier = &svq->hdev_call;
++    file.fd = event_notifier_get_fd(event_notifier);
++    r = vhost_vdpa_set_vring_dev_call(dev, &file);
++    if (unlikely(r != 0)) {
++        error_setg_errno(errp, -r, "Can't set device call fd");
+     }
+     return r == 0;
+@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_kick(struct vhost_dev *dev,
+ static int vhost_vdpa_set_vring_call(struct vhost_dev *dev,
+                                        struct vhost_vring_file *file)
+ {
+-    trace_vhost_vdpa_set_vring_call(dev, file->index, file->fd);
+-    return vhost_vdpa_call(dev, VHOST_SET_VRING_CALL, file);
++    struct vhost_vdpa *v = dev->opaque;
++
++    if (v->shadow_vqs_enabled) {
++        int vdpa_idx = file->index - dev->vq_index;
++        VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, vdpa_idx);
++
++        vhost_svq_set_svq_call_fd(svq, file->fd);
++        return 0;
++    } else {
++        return vhost_vdpa_set_vring_dev_call(dev, file);
++    }
+ }
+ static int vhost_vdpa_get_features(struct vhost_dev *dev,
+--
+.7.4

-New patch
+[PULL V2 05/15] vhost: Add vhost_svq_valid_features to shadow vq
+From: Eugenio Pérez <eperezma@redhat.com>
+This allows SVQ to negotiate features with the guest and the device. For
+the device, SVQ is a driver. While this function bypasses all
+non-transport features, it needs to disable the features that SVQ does
+not support when forwarding buffers. This includes packed vq layout,
+indirect descriptors or event idx.
+Future changes can add support to offer more features to the guest,
+since the use of VirtQueue gives this for free. This is left out at the
+moment for simplicity.
+Acked-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+---
+ hw/virtio/vhost-shadow-virtqueue.c | 44 ++++++++++++++++++++++++++++++++++++++
+ hw/virtio/vhost-shadow-virtqueue.h |  2 ++
+ hw/virtio/vhost-vdpa.c             | 15 +++++++++++++
+files changed, 61 insertions(+)
+diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/virtio/vhost-shadow-virtqueue.c
++++ b/hw/virtio/vhost-shadow-virtqueue.c
+@@ -XXX,XX +XXX,XX @@
+ #include "hw/virtio/vhost-shadow-virtqueue.h"
+ #include "qemu/error-report.h"
++#include "qapi/error.h"
+ #include "qemu/main-loop.h"
+ #include "linux-headers/linux/vhost.h"
+ /**
++ * Validate the transport device features that both guests can use with the SVQ
++ * and SVQs can use with the device.
++ *
++ * @dev_features: The features
++ * @errp: Error pointer
++ */
++bool vhost_svq_valid_features(uint64_t features, Error **errp)
++{
++    bool ok = true;
++    uint64_t svq_features = features;
++
++    for (uint64_t b = VIRTIO_TRANSPORT_F_START; b <= VIRTIO_TRANSPORT_F_END;
++         ++b) {
++        switch (b) {
++        case VIRTIO_F_ANY_LAYOUT:
++            continue;
++
++        case VIRTIO_F_ACCESS_PLATFORM:
++            /* SVQ trust in the host's IOMMU to translate addresses */
++        case VIRTIO_F_VERSION_1:
++            /* SVQ trust that the guest vring is little endian */
++            if (!(svq_features & BIT_ULL(b))) {
++                set_bit(b, &svq_features);
++                ok = false;
++            }
++            continue;
++
++        default:
++            if (svq_features & BIT_ULL(b)) {
++                clear_bit(b, &svq_features);
++                ok = false;
++            }
++        }
++    }
++
++    if (!ok) {
++        error_setg(errp, "SVQ Invalid device feature flags, offer: 0x%"PRIx64
++                         ", ok: 0x%"PRIx64, features, svq_features);
++    }
++    return ok;
++}
++
++/**
+  * Forward guest notifications.
+  *
+  * @n: guest kick event notifier, the one that guest set to notify svq.
+diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/virtio/vhost-shadow-virtqueue.h
++++ b/hw/virtio/vhost-shadow-virtqueue.h
+@@ -XXX,XX +XXX,XX @@ typedef struct VhostShadowVirtqueue {
+     EventNotifier svq_call;
+ } VhostShadowVirtqueue;
++bool vhost_svq_valid_features(uint64_t features, Error **errp);
++
+ void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd);
+ void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd);
+diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/virtio/vhost-vdpa.c
++++ b/hw/virtio/vhost-vdpa.c
+@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
+                                Error **errp)
+ {
+     g_autoptr(GPtrArray) shadow_vqs = NULL;
++    uint64_t dev_features, svq_features;
++    int r;
++    bool ok;
+     if (!v->shadow_vqs_enabled) {
+         return 0;
+     }
++    r = hdev->vhost_ops->vhost_get_features(hdev, &dev_features);
++    if (r != 0) {
++        error_setg_errno(errp, -r, "Can't get vdpa device features");
++        return r;
++    }
++
++    svq_features = dev_features;
++    ok = vhost_svq_valid_features(svq_features, errp);
++    if (unlikely(!ok)) {
++        return -1;
++    }
++
+     shadow_vqs = g_ptr_array_new_full(hdev->nvqs, vhost_svq_free);
+     for (unsigned n = 0; n < hdev->nvqs; ++n) {
+         g_autoptr(VhostShadowVirtqueue) svq = vhost_svq_new();
+--
+.7.4

-New patch
+[PULL V2 06/15] virtio: Add vhost_svq_get_vring_addr
+From: Eugenio Pérez <eperezma@redhat.com>
+It reports the shadow virtqueue address from qemu virtual address space.
+Since this will be different from the guest's vaddr, but the device can
+access it, SVQ takes special care about its alignment & lack of garbage
+data. It assumes that IOMMU will work in host_page_size ranges for that.
+Acked-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+---
+ hw/virtio/vhost-shadow-virtqueue.c | 29 +++++++++++++++++++++++++++++
+ hw/virtio/vhost-shadow-virtqueue.h |  9 +++++++++
+files changed, 38 insertions(+)
+diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/virtio/vhost-shadow-virtqueue.c
++++ b/hw/virtio/vhost-shadow-virtqueue.c
+@@ -XXX,XX +XXX,XX @@ void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd)
+ }
+ /**
++ * Get the shadow vq vring address.
++ * @svq: Shadow virtqueue
++ * @addr: Destination to store address
++ */
++void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq,
++                              struct vhost_vring_addr *addr)
++{
++    addr->desc_user_addr = (uint64_t)svq->vring.desc;
++    addr->avail_user_addr = (uint64_t)svq->vring.avail;
++    addr->used_user_addr = (uint64_t)svq->vring.used;
++}
++
++size_t vhost_svq_driver_area_size(const VhostShadowVirtqueue *svq)
++{
++    size_t desc_size = sizeof(vring_desc_t) * svq->vring.num;
++    size_t avail_size = offsetof(vring_avail_t, ring) +
++                                             sizeof(uint16_t) * svq->vring.num;
++
++    return ROUND_UP(desc_size + avail_size, qemu_real_host_page_size);
++}
++
++size_t vhost_svq_device_area_size(const VhostShadowVirtqueue *svq)
++{
++    size_t used_size = offsetof(vring_used_t, ring) +
++                                    sizeof(vring_used_elem_t) * svq->vring.num;
++    return ROUND_UP(used_size, qemu_real_host_page_size);
++}
++
++/**
+  * Set a new file descriptor for the guest to kick the SVQ and notify for avail
+  *
+  * @svq: The svq
+diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/virtio/vhost-shadow-virtqueue.h
++++ b/hw/virtio/vhost-shadow-virtqueue.h
+@@ -XXX,XX +XXX,XX @@
+ #define VHOST_SHADOW_VIRTQUEUE_H
+ #include "qemu/event_notifier.h"
++#include "hw/virtio/virtio.h"
++#include "standard-headers/linux/vhost_types.h"
+ /* Shadow virtqueue to relay notifications */
+ typedef struct VhostShadowVirtqueue {
++    /* Shadow vring */
++    struct vring vring;
++
+     /* Shadow kick notifier, sent to vhost */
+     EventNotifier hdev_kick;
+     /* Shadow call notifier, sent to vhost */
+@@ -XXX,XX +XXX,XX @@ bool vhost_svq_valid_features(uint64_t features, Error **errp);
+ void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd);
+ void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd);
++void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq,
++                              struct vhost_vring_addr *addr);
++size_t vhost_svq_driver_area_size(const VhostShadowVirtqueue *svq);
++size_t vhost_svq_device_area_size(const VhostShadowVirtqueue *svq);
+ void vhost_svq_stop(VhostShadowVirtqueue *svq);
+--
+.7.4

-New patch
+[PULL V2 07/15] vdpa: adapt vhost_ops callbacks to svq
+From: Eugenio Pérez <eperezma@redhat.com>
+First half of the buffers forwarding part, preparing vhost-vdpa
+callbacks to SVQ to offer it. QEMU cannot enable it at this moment, so
+this is effectively dead code at the moment, but it helps to reduce
+patch size.
+Acked-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+---
+ hw/virtio/vhost-vdpa.c | 48 +++++++++++++++++++++++++++++++++++++++++-------
+file changed, 41 insertions(+), 7 deletions(-)
+diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/virtio/vhost-vdpa.c
++++ b/hw/virtio/vhost-vdpa.c
+@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_get_config(struct vhost_dev *dev, uint8_t *config,
+     return ret;
+  }
++static int vhost_vdpa_set_dev_vring_base(struct vhost_dev *dev,
++                                         struct vhost_vring_state *ring)
++{
++    trace_vhost_vdpa_set_vring_base(dev, ring->index, ring->num);
++    return vhost_vdpa_call(dev, VHOST_SET_VRING_BASE, ring);
++}
++
+ static int vhost_vdpa_set_vring_dev_kick(struct vhost_dev *dev,
+                                          struct vhost_vring_file *file)
+ {
+@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_dev_call(struct vhost_dev *dev,
+     return vhost_vdpa_call(dev, VHOST_SET_VRING_CALL, file);
+ }
++static int vhost_vdpa_set_vring_dev_addr(struct vhost_dev *dev,
++                                         struct vhost_vring_addr *addr)
++{
++    trace_vhost_vdpa_set_vring_addr(dev, addr->index, addr->flags,
++                                addr->desc_user_addr, addr->used_user_addr,
++                                addr->avail_user_addr,
++                                addr->log_guest_addr);
++
++    return vhost_vdpa_call(dev, VHOST_SET_VRING_ADDR, addr);
++
++}
++
+ /**
+  * Set the shadow virtqueue descriptors to the device
+  *
+@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_log_base(struct vhost_dev *dev, uint64_t base,
+ static int vhost_vdpa_set_vring_addr(struct vhost_dev *dev,
+                                        struct vhost_vring_addr *addr)
+ {
+-    trace_vhost_vdpa_set_vring_addr(dev, addr->index, addr->flags,
+-                                    addr->desc_user_addr, addr->used_user_addr,
+-                                    addr->avail_user_addr,
+-                                    addr->log_guest_addr);
+-    return vhost_vdpa_call(dev, VHOST_SET_VRING_ADDR, addr);
++    struct vhost_vdpa *v = dev->opaque;
++
++    if (v->shadow_vqs_enabled) {
++        /*
++         * Device vring addr was set at device start. SVQ base is handled by
++         * VirtQueue code.
++         */
++        return 0;
++    }
++
++    return vhost_vdpa_set_vring_dev_addr(dev, addr);
+ }
+ static int vhost_vdpa_set_vring_num(struct vhost_dev *dev,
+@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_num(struct vhost_dev *dev,
+ static int vhost_vdpa_set_vring_base(struct vhost_dev *dev,
+                                        struct vhost_vring_state *ring)
+ {
+-    trace_vhost_vdpa_set_vring_base(dev, ring->index, ring->num);
+-    return vhost_vdpa_call(dev, VHOST_SET_VRING_BASE, ring);
++    struct vhost_vdpa *v = dev->opaque;
++
++    if (v->shadow_vqs_enabled) {
++        /*
++         * Device vring base was set at device start. SVQ base is handled by
++         * VirtQueue code.
++         */
++        return 0;
++    }
++
++    return vhost_vdpa_set_dev_vring_base(dev, ring);
+ }
+ static int vhost_vdpa_get_vring_base(struct vhost_dev *dev,
+--
+.7.4

-New patch
+[PULL V2 08/15] vhost: Shadow virtqueue buffers forwarding
+From: Eugenio Pérez <eperezma@redhat.com>
 Initial version of shadow virtqueue that actually forward buffers. There
 is no iommu support at the moment, and that will be addressed in future
 patches of this series. Since all vhost-vdpa devices use forced IOMMU,
 this means that SVQ is not usable at this point of the series on any
 device.
 For simplicity it only supports modern devices, that expects vring
 in little endian, with split ring and no event idx or indirect
 descriptors. Support for them will not be added in this series.
 It reuses the VirtQueue code for the device part. The driver part is
 based on Linux's virtio_ring driver, but with stripped functionality
 and optimizations so it's easier to review.
 However, forwarding buffers have some particular pieces: One of the most
 unexpected ones is that a guest's buffer can expand through more than
 one descriptor in SVQ. While this is handled gracefully by qemu's
 emulated virtio devices, it may cause unexpected SVQ queue full. This
 patch also solves it by checking for this condition at both guest's
 kicks and device's calls. The code may be more elegant in the future if
 SVQ code runs in its own iocontext.
 Acked-by: Michael S. Tsirkin <mst@redhat.com>
 Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
 Signed-off-by: Jason Wang <jasowang@redhat.com>
 ---
  hw/virtio/vhost-shadow-virtqueue.c | 354 ++++++++++++++++++++++++++++++++++++-
  hw/virtio/vhost-shadow-virtqueue.h |  26 +++
  hw/virtio/vhost-vdpa.c             | 159 ++++++++++++++++-
 files changed, 527 insertions(+), 12 deletions(-)
 diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/virtio/vhost-shadow-virtqueue.c
 +++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -XXX,XX +XXX,XX @@
  #include "qemu/error-report.h"
  #include "qapi/error.h"
  #include "qemu/main-loop.h"
 +#include "qemu/log.h"
 +#include "qemu/memalign.h"
  #include "linux-headers/linux/vhost.h"
  /**
@@ -XXX,XX +XXX,XX @@ bool vhost_svq_valid_features(uint64_t features, Error **errp)
  }
  /**
 - * Forward guest notifications.
 + * Number of descriptors that the SVQ can make available from the guest.
 + *
 + * @svq: The svq
 + */
 +static uint16_t vhost_svq_available_slots(const VhostShadowVirtqueue *svq)
 +{
 +    return svq->vring.num - (svq->shadow_avail_idx - svq->shadow_used_idx);
 +}
 +
 +static void vhost_vring_write_descs(VhostShadowVirtqueue *svq,
 +                                    const struct iovec *iovec,
 +                                    size_t num, bool more_descs, bool write)
 +{
 +    uint16_t i = svq->free_head, last = svq->free_head;
 +    unsigned n;
 +    uint16_t flags = write ? cpu_to_le16(VRING_DESC_F_WRITE) : 0;
 +    vring_desc_t *descs = svq->vring.desc;
 +
 +    if (num == 0) {
 +        return;
 +    }
 +
 +    for (n = 0; n < num; n++) {
 +        if (more_descs || (n + 1 < num)) {
 +            descs[i].flags = flags | cpu_to_le16(VRING_DESC_F_NEXT);
 +        } else {
 +            descs[i].flags = flags;
 +        }
 +        descs[i].addr = cpu_to_le64((hwaddr)iovec[n].iov_base);
 +        descs[i].len = cpu_to_le32(iovec[n].iov_len);
 +
 +        last = i;
 +        i = cpu_to_le16(descs[i].next);
 +    }
 +
 +    svq->free_head = le16_to_cpu(descs[last].next);
 +}
 +
 +static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
 +                                VirtQueueElement *elem,
 +                                unsigned *head)
 +{
 +    unsigned avail_idx;
 +    vring_avail_t *avail = svq->vring.avail;
 +
 +    *head = svq->free_head;
 +
 +    /* We need some descriptors here */
 +    if (unlikely(!elem->out_num && !elem->in_num)) {
 +        qemu_log_mask(LOG_GUEST_ERROR,
 +            "Guest provided element with no descriptors");
 +        return false;
 +    }
 +
 +    vhost_vring_write_descs(svq, elem->out_sg, elem->out_num,
 +                            elem->in_num > 0, false);
 +    vhost_vring_write_descs(svq, elem->in_sg, elem->in_num, false, true);
 +
 +    /*
 +     * Put the entry in the available array (but don't update avail->idx until
 +     * they do sync).
 +     */
 +    avail_idx = svq->shadow_avail_idx & (svq->vring.num - 1);
 +    avail->ring[avail_idx] = cpu_to_le16(*head);
 +    svq->shadow_avail_idx++;
 +
 +    /* Update the avail index after write the descriptor */
 +    smp_wmb();
 +    avail->idx = cpu_to_le16(svq->shadow_avail_idx);
 +
 +    return true;
 +}
 +
 +static bool vhost_svq_add(VhostShadowVirtqueue *svq, VirtQueueElement *elem)
 +{
 +    unsigned qemu_head;
 +    bool ok = vhost_svq_add_split(svq, elem, &qemu_head);
 +    if (unlikely(!ok)) {
 +        return false;
 +    }
 +
 +    svq->ring_id_maps[qemu_head] = elem;
 +    return true;
 +}
 +
 +static void vhost_svq_kick(VhostShadowVirtqueue *svq)
 +{
 +    /*
 +     * We need to expose the available array entries before checking the used
 +     * flags
 +     */
 +    smp_mb();
 +    if (svq->vring.used->flags & VRING_USED_F_NO_NOTIFY) {
 +        return;
 +    }
 +
 +    event_notifier_set(&svq->hdev_kick);
 +}
 +
 +/**
 + * Forward available buffers.
 + *
 + * @svq: Shadow VirtQueue
 + *
 + * Note that this function does not guarantee that all guest's available
 + * buffers are available to the device in SVQ avail ring. The guest may have
 + * exposed a GPA / GIOVA contiguous buffer, but it may not be contiguous in
 + * qemu vaddr.
 + *
 + * If that happens, guest's kick notifications will be disabled until the
 + * device uses some buffers.
 + */
 +static void vhost_handle_guest_kick(VhostShadowVirtqueue *svq)
 +{
 +    /* Clear event notifier */
 +    event_notifier_test_and_clear(&svq->svq_kick);
 +
 +    /* Forward to the device as many available buffers as possible */
 +    do {
 +        virtio_queue_set_notification(svq->vq, false);
 +
 +        while (true) {
 +            VirtQueueElement *elem;
 +            bool ok;
 +
 +            if (svq->next_guest_avail_elem) {
 +                elem = g_steal_pointer(&svq->next_guest_avail_elem);
 +            } else {
 +                elem = virtqueue_pop(svq->vq, sizeof(*elem));
 +            }
 +
 +            if (!elem) {
 +                break;
 +            }
 +
 +            if (elem->out_num + elem->in_num >
 +                vhost_svq_available_slots(svq)) {
 +                /*
 +                 * This condition is possible since a contiguous buffer in GPA
 +                 * does not imply a contiguous buffer in qemu's VA
 +                 * scatter-gather segments. If that happens, the buffer exposed
 +                 * to the device needs to be a chain of descriptors at this
 +                 * moment.
 +                 *
 +                 * SVQ cannot hold more available buffers if we are here:
 +                 * queue the current guest descriptor and ignore further kicks
 +                 * until some elements are used.
 +                 */
 +                svq->next_guest_avail_elem = elem;
 +                return;
 +            }
 +
 +            ok = vhost_svq_add(svq, elem);
 +            if (unlikely(!ok)) {
 +                /* VQ is broken, just return and ignore any other kicks */
 +                return;
 +            }
 +            vhost_svq_kick(svq);
 +        }
 +
 +        virtio_queue_set_notification(svq->vq, true);
 +    } while (!virtio_queue_empty(svq->vq));
 +}
 +
 +/**
 + * Handle guest's kick.
   *
   * @n: guest kick event notifier, the one that guest set to notify svq.
   */
 -static void vhost_handle_guest_kick(EventNotifier *n)
 +static void vhost_handle_guest_kick_notifier(EventNotifier *n)
  {
      VhostShadowVirtqueue *svq = container_of(n, VhostShadowVirtqueue,
                                               svq_kick);
      event_notifier_test_and_clear(n);
 -    event_notifier_set(&svq->hdev_kick);
 +    vhost_handle_guest_kick(svq);
 +}
 +
 +static bool vhost_svq_more_used(VhostShadowVirtqueue *svq)
 +{
 +    if (svq->last_used_idx != svq->shadow_used_idx) {
 +        return true;
 +    }
 +
 +    svq->shadow_used_idx = cpu_to_le16(svq->vring.used->idx);
 +
 +    return svq->last_used_idx != svq->shadow_used_idx;
  }
  /**
 - * Forward vhost notifications
 + * Enable vhost device calls after disable them.
 + *
 + * @svq: The svq
 + *
 + * It returns false if there are pending used buffers from the vhost device,
 + * avoiding the possible races between SVQ checking for more work and enabling
 + * callbacks. True if SVQ used vring has no more pending buffers.
 + */
 +static bool vhost_svq_enable_notification(VhostShadowVirtqueue *svq)
 +{
 +    svq->vring.avail->flags &= ~cpu_to_le16(VRING_AVAIL_F_NO_INTERRUPT);
 +    /* Make sure the flag is written before the read of used_idx */
 +    smp_mb();
 +    return !vhost_svq_more_used(svq);
 +}
 +
 +static void vhost_svq_disable_notification(VhostShadowVirtqueue *svq)
 +{
 +    svq->vring.avail->flags |= cpu_to_le16(VRING_AVAIL_F_NO_INTERRUPT);
 +}
 +
 +static VirtQueueElement *vhost_svq_get_buf(VhostShadowVirtqueue *svq,
 +                                           uint32_t *len)
 +{
 +    vring_desc_t *descs = svq->vring.desc;
 +    const vring_used_t *used = svq->vring.used;
 +    vring_used_elem_t used_elem;
 +    uint16_t last_used;
 +
 +    if (!vhost_svq_more_used(svq)) {
 +        return NULL;
 +    }
 +
 +    /* Only get used array entries after they have been exposed by dev */
 +    smp_rmb();
 +    last_used = svq->last_used_idx & (svq->vring.num - 1);
 +    used_elem.id = le32_to_cpu(used->ring[last_used].id);
 +    used_elem.len = le32_to_cpu(used->ring[last_used].len);
 +
 +    svq->last_used_idx++;
 +    if (unlikely(used_elem.id >= svq->vring.num)) {
 +        qemu_log_mask(LOG_GUEST_ERROR, "Device %s says index %u is used",
 +                      svq->vdev->name, used_elem.id);
 +        return NULL;
 +    }
 +
 +    if (unlikely(!svq->ring_id_maps[used_elem.id])) {
 +        qemu_log_mask(LOG_GUEST_ERROR,
 +            "Device %s says index %u is used, but it was not available",
 +            svq->vdev->name, used_elem.id);
 +        return NULL;
 +    }
 +
 +    descs[used_elem.id].next = svq->free_head;
 +    svq->free_head = used_elem.id;
 +
 +    *len = used_elem.len;
 +    return g_steal_pointer(&svq->ring_id_maps[used_elem.id]);
 +}
 +
 +static void vhost_svq_flush(VhostShadowVirtqueue *svq,
 +                            bool check_for_avail_queue)
 +{
 +    VirtQueue *vq = svq->vq;
 +
 +    /* Forward as many used buffers as possible. */
 +    do {
 +        unsigned i = 0;
 +
 +        vhost_svq_disable_notification(svq);
 +        while (true) {
 +            uint32_t len;
 +            g_autofree VirtQueueElement *elem = vhost_svq_get_buf(svq, &len);
 +            if (!elem) {
 +                break;
 +            }
 +
 +            if (unlikely(i >= svq->vring.num)) {
 +                qemu_log_mask(LOG_GUEST_ERROR,
 +                         "More than %u used buffers obtained in a %u size SVQ",
 +                         i, svq->vring.num);
 +                virtqueue_fill(vq, elem, len, i);
 +                virtqueue_flush(vq, i);
 +                return;
 +            }
 +            virtqueue_fill(vq, elem, len, i++);
 +        }
 +
 +        virtqueue_flush(vq, i);
 +        event_notifier_set(&svq->svq_call);
 +
 +        if (check_for_avail_queue && svq->next_guest_avail_elem) {
 +            /*
 +             * Avail ring was full when vhost_svq_flush was called, so it's a
 +             * good moment to make more descriptors available if possible.
 +             */
 +            vhost_handle_guest_kick(svq);
 +        }
 +    } while (!vhost_svq_enable_notification(svq));
 +}
 +
 +/**
 + * Forward used buffers.
   *
   * @n: hdev call event notifier, the one that device set to notify svq.
 + *
 + * Note that we are not making any buffers available in the loop, there is no
 + * way that it runs more than virtqueue size times.
   */
  static void vhost_svq_handle_call(EventNotifier *n)
  {
      VhostShadowVirtqueue *svq = container_of(n, VhostShadowVirtqueue,
                                               hdev_call);
      event_notifier_test_and_clear(n);
 -    event_notifier_set(&svq->svq_call);
 +    vhost_svq_flush(svq, true);
  }
  /**
@@ -XXX,XX +XXX,XX @@ void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd)
      if (poll_start) {
          event_notifier_init_fd(svq_kick, svq_kick_fd);
          event_notifier_set(svq_kick);
 -        event_notifier_set_handler(svq_kick, vhost_handle_guest_kick);
 +        event_notifier_set_handler(svq_kick, vhost_handle_guest_kick_notifier);
 +    }
 +}
 +
 +/**
 + * Start the shadow virtqueue operation.
 + *
 + * @svq: Shadow Virtqueue
 + * @vdev: VirtIO device
 + * @vq: Virtqueue to shadow
 + */
 +void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
 +                     VirtQueue *vq)
 +{
 +    size_t desc_size, driver_size, device_size;
 +
 +    svq->next_guest_avail_elem = NULL;
 +    svq->shadow_avail_idx = 0;
 +    svq->shadow_used_idx = 0;
 +    svq->last_used_idx = 0;
 +    svq->vdev = vdev;
 +    svq->vq = vq;
 +
 +    svq->vring.num = virtio_queue_get_num(vdev, virtio_get_queue_index(vq));
 +    driver_size = vhost_svq_driver_area_size(svq);
 +    device_size = vhost_svq_device_area_size(svq);
 +    svq->vring.desc = qemu_memalign(qemu_real_host_page_size, driver_size);
 +    desc_size = sizeof(vring_desc_t) * svq->vring.num;
 +    svq->vring.avail = (void *)((char *)svq->vring.desc + desc_size);
 +    memset(svq->vring.desc, 0, driver_size);
 +    svq->vring.used = qemu_memalign(qemu_real_host_page_size, device_size);
 +    memset(svq->vring.used, 0, device_size);
 +    svq->ring_id_maps = g_new0(VirtQueueElement *, svq->vring.num);
 +    for (unsigned i = 0; i < svq->vring.num - 1; i++) {
 +        svq->vring.desc[i].next = cpu_to_le16(i + 1);
      }
  }
@@ -XXX,XX +XXX,XX @@ void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd)
  void vhost_svq_stop(VhostShadowVirtqueue *svq)
  {
      event_notifier_set_handler(&svq->svq_kick, NULL);
 +    g_autofree VirtQueueElement *next_avail_elem = NULL;
 +
 +    if (!svq->vq) {
 +        return;
 +    }
 +
 +    /* Send all pending used descriptors to guest */
 +    vhost_svq_flush(svq, false);
 +
 +    for (unsigned i = 0; i < svq->vring.num; ++i) {
 +        g_autofree VirtQueueElement *elem = NULL;
 +        elem = g_steal_pointer(&svq->ring_id_maps[i]);
 +        if (elem) {
 +            virtqueue_detach_element(svq->vq, elem, 0);
 +        }
 +    }
 +
 +    next_avail_elem = g_steal_pointer(&svq->next_guest_avail_elem);
 +    if (next_avail_elem) {
 +        virtqueue_detach_element(svq->vq, next_avail_elem, 0);
 +    }
 +    svq->vq = NULL;
 +    g_free(svq->ring_id_maps);
 +    qemu_vfree(svq->vring.desc);
 +    qemu_vfree(svq->vring.used);
  }
  /**
 diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/virtio/vhost-shadow-virtqueue.h
 +++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -XXX,XX +XXX,XX @@ typedef struct VhostShadowVirtqueue {
      /* Guest's call notifier, where the SVQ calls guest. */
      EventNotifier svq_call;
 +
 +    /* Virtio queue shadowing */
 +    VirtQueue *vq;
 +
 +    /* Virtio device */
 +    VirtIODevice *vdev;
 +
 +    /* Map for use the guest's descriptors */
 +    VirtQueueElement **ring_id_maps;
 +
 +    /* Next VirtQueue element that guest made available */
 +    VirtQueueElement *next_guest_avail_elem;
 +
 +    /* Next head to expose to the device */
 +    uint16_t shadow_avail_idx;
 +
 +    /* Next free descriptor */
 +    uint16_t free_head;
 +
 +    /* Last seen used idx */
 +    uint16_t shadow_used_idx;
 +
 +    /* Next head to consume from the device */
 +    uint16_t last_used_idx;
  } VhostShadowVirtqueue;
  bool vhost_svq_valid_features(uint64_t features, Error **errp);
@@ -XXX,XX +XXX,XX @@ void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq,
  size_t vhost_svq_driver_area_size(const VhostShadowVirtqueue *svq);
  size_t vhost_svq_device_area_size(const VhostShadowVirtqueue *svq);
 +void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
 +                     VirtQueue *vq);
  void vhost_svq_stop(VhostShadowVirtqueue *svq);
  VhostShadowVirtqueue *vhost_svq_new(void);
 diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/virtio/vhost-vdpa.c
 +++ b/hw/virtio/vhost-vdpa.c
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_dev_addr(struct vhost_dev *dev,
   * Note that this function does not rewind kick file descriptor if cannot set
   * call one.
   */
 -static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
 -                                 VhostShadowVirtqueue *svq,
 -                                 unsigned idx,
 -                                 Error **errp)
 +static int vhost_vdpa_svq_set_fds(struct vhost_dev *dev,
 +                                  VhostShadowVirtqueue *svq,
 +                                  unsigned idx,
 +                                  Error **errp)
  {
      struct vhost_vring_file file = {
          .index = dev->vq_index + idx,
@@ -XXX,XX +XXX,XX @@ static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
      r = vhost_vdpa_set_vring_dev_kick(dev, &file);
      if (unlikely(r != 0)) {
          error_setg_errno(errp, -r, "Can't set device kick fd");
 -        return false;
 +        return r;
      }
      event_notifier = &svq->hdev_call;
@@ -XXX,XX +XXX,XX @@ static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
          error_setg_errno(errp, -r, "Can't set device call fd");
      }
 +    return r;
 +}
 +
 +/**
 + * Unmap a SVQ area in the device
 + */
 +static bool vhost_vdpa_svq_unmap_ring(struct vhost_vdpa *v, hwaddr iova,
 +                                      hwaddr size)
 +{
 +    int r;
 +
 +    size = ROUND_UP(size, qemu_real_host_page_size);
 +    r = vhost_vdpa_dma_unmap(v, iova, size);
 +    return r == 0;
 +}
 +
 +static bool vhost_vdpa_svq_unmap_rings(struct vhost_dev *dev,
 +                                       const VhostShadowVirtqueue *svq)
 +{
 +    struct vhost_vdpa *v = dev->opaque;
 +    struct vhost_vring_addr svq_addr;
 +    size_t device_size = vhost_svq_device_area_size(svq);
 +    size_t driver_size = vhost_svq_driver_area_size(svq);
 +    bool ok;
 +
 +    vhost_svq_get_vring_addr(svq, &svq_addr);
 +
 +    ok = vhost_vdpa_svq_unmap_ring(v, svq_addr.desc_user_addr, driver_size);
 +    if (unlikely(!ok)) {
 +        return false;
 +    }
 +
 +    return vhost_vdpa_svq_unmap_ring(v, svq_addr.used_user_addr, device_size);
 +}
 +
 +/**
 + * Map the shadow virtqueue rings in the device
 + *
 + * @dev: The vhost device
 + * @svq: The shadow virtqueue
 + * @addr: Assigned IOVA addresses
 + * @errp: Error pointer
 + */
 +static bool vhost_vdpa_svq_map_rings(struct vhost_dev *dev,
 +                                     const VhostShadowVirtqueue *svq,
 +                                     struct vhost_vring_addr *addr,
 +                                     Error **errp)
 +{
 +    struct vhost_vdpa *v = dev->opaque;
 +    size_t device_size = vhost_svq_device_area_size(svq);
 +    size_t driver_size = vhost_svq_driver_area_size(svq);
 +    int r;
 +
 +    ERRP_GUARD();
 +    vhost_svq_get_vring_addr(svq, addr);
 +
 +    r = vhost_vdpa_dma_map(v, addr->desc_user_addr, driver_size,
 +                           (void *)addr->desc_user_addr, true);
 +    if (unlikely(r != 0)) {
 +        error_setg_errno(errp, -r, "Cannot create vq driver region: ");
 +        return false;
 +    }
 +
 +    r = vhost_vdpa_dma_map(v, addr->used_user_addr, device_size,
 +                           (void *)addr->used_user_addr, false);
 +    if (unlikely(r != 0)) {
 +        error_setg_errno(errp, -r, "Cannot create vq device region: ");
 +    }
 +
 +    return r == 0;
 +}
 +
 +static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
 +                                 VhostShadowVirtqueue *svq,
 +                                 unsigned idx,
 +                                 Error **errp)
 +{
 +    uint16_t vq_index = dev->vq_index + idx;
 +    struct vhost_vring_state s = {
 +        .index = vq_index,
 +    };
 +    int r;
 +
 +    r = vhost_vdpa_set_dev_vring_base(dev, &s);
 +    if (unlikely(r)) {
 +        error_setg_errno(errp, -r, "Cannot set vring base");
 +        return false;
 +    }
 +
 +    r = vhost_vdpa_svq_set_fds(dev, svq, idx, errp);
      return r == 0;
  }
@@ -XXX,XX +XXX,XX @@ static bool vhost_vdpa_svqs_start(struct vhost_dev *dev)
      }
      for (i = 0; i < v->shadow_vqs->len; ++i) {
 +        VirtQueue *vq = virtio_get_queue(dev->vdev, dev->vq_index + i);
          VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, i);
 +        struct vhost_vring_addr addr = {
 +            .index = i,
 +        };
 +        int r;
          bool ok = vhost_vdpa_svq_setup(dev, svq, i, &err);
          if (unlikely(!ok)) {
 -            error_reportf_err(err, "Cannot setup SVQ %u: ", i);
 +            goto err;
 +        }
 +
 +        vhost_svq_start(svq, dev->vdev, vq);
 +        ok = vhost_vdpa_svq_map_rings(dev, svq, &addr, &err);
 +        if (unlikely(!ok)) {
 +            goto err_map;
 +        }
 +
 +        /* Override vring GPA set by vhost subsystem */
 +        r = vhost_vdpa_set_vring_dev_addr(dev, &addr);
 +        if (unlikely(r != 0)) {
 +            error_setg_errno(&err, -r, "Cannot set device address");
 +            goto err_set_addr;
 +        }
 +    }
 +
 +    return true;
 +
 +err_set_addr:
 +    vhost_vdpa_svq_unmap_rings(dev, g_ptr_array_index(v->shadow_vqs, i));
 +
 +err_map:
 +    vhost_svq_stop(g_ptr_array_index(v->shadow_vqs, i));
 +
 +err:
 +    error_reportf_err(err, "Cannot setup SVQ %u: ", i);
 +    for (unsigned j = 0; j < i; ++j) {
 +        VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, j);
 +        vhost_vdpa_svq_unmap_rings(dev, svq);
 +        vhost_svq_stop(svq);
 +    }
 +
 +    return false;
 +}
 +
 +static bool vhost_vdpa_svqs_stop(struct vhost_dev *dev)
 +{
 +    struct vhost_vdpa *v = dev->opaque;
 +
 +    if (!v->shadow_vqs) {
 +        return true;
 +    }
 +
 +    for (unsigned i = 0; i < v->shadow_vqs->len; ++i) {
 +        VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs,
 +                                                      i);
 +        bool ok = vhost_vdpa_svq_unmap_rings(dev, svq);
 +        if (unlikely(!ok)) {
              return false;
          }
      }
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
          }
          vhost_vdpa_set_vring_ready(dev);
      } else {
 +        ok = vhost_vdpa_svqs_stop(dev);
 +        if (unlikely(!ok)) {
 +            return -1;
 +        }
          vhost_vdpa_host_notifiers_uninit(dev, dev->nvqs);
      }
 --
 .7.4

-New patch
+[PULL V2 09/15] util: Add iova_tree_alloc_map
+From: Eugenio Pérez <eperezma@redhat.com>
 This iova tree function allows it to look for a hole in allocated
 regions and return a totally new translation for a given translated
 address.
 It's usage is mainly to allow devices to access qemu address space,
 remapping guest's one into a new iova space where qemu can add chunks of
 addresses.
 Acked-by: Michael S. Tsirkin <mst@redhat.com>
 Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
 Reviewed-by: Peter Xu <peterx@redhat.com>
 Signed-off-by: Jason Wang <jasowang@redhat.com>
 ---
  include/qemu/iova-tree.h |  18 +++++++
  util/iova-tree.c         | 135 +++++++++++++++++++++++++++++++++++++++++++++++
 files changed, 153 insertions(+)
 diff --git a/include/qemu/iova-tree.h b/include/qemu/iova-tree.h
 index XXXXXXX..XXXXXXX 100644
 --- a/include/qemu/iova-tree.h
 +++ b/include/qemu/iova-tree.h
@@ -XXX,XX +XXX,XX @@
  #define  IOVA_OK           (0)
  #define  IOVA_ERR_INVALID  (-1) /* Invalid parameters */
  #define  IOVA_ERR_OVERLAP  (-2) /* IOVA range overlapped */
 +#define  IOVA_ERR_NOMEM    (-3) /* Cannot allocate */
  typedef struct IOVATree IOVATree;
  typedef struct DMAMap {
@@ -XXX,XX +XXX,XX @@ const DMAMap *iova_tree_find_address(const IOVATree *tree, hwaddr iova);
  void iova_tree_foreach(IOVATree *tree, iova_tree_iterator iterator);
  /**
 + * iova_tree_alloc_map:
 + *
 + * @tree: the iova tree to allocate from
 + * @map: the new map (as translated addr & size) to allocate in the iova region
 + * @iova_begin: the minimum address of the allocation
 + * @iova_end: the maximum addressable direction of the allocation
 + *
 + * Allocates a new region of a given size, between iova_min and iova_max.
 + *
 + * Return: Same as iova_tree_insert, but cannot overlap and can return error if
 + * iova tree is out of free contiguous range. The caller gets the assigned iova
 + * in map->iova.
 + */
 +int iova_tree_alloc_map(IOVATree *tree, DMAMap *map, hwaddr iova_begin,
 +                        hwaddr iova_end);
 +
 +/**
   * iova_tree_destroy:
   *
   * @tree: the iova tree to destroy
 diff --git a/util/iova-tree.c b/util/iova-tree.c
 index XXXXXXX..XXXXXXX 100644
 --- a/util/iova-tree.c
 +++ b/util/iova-tree.c
@@ -XXX,XX +XXX,XX @@ struct IOVATree {
      GTree *tree;
  };
 +/* Args to pass to iova_tree_alloc foreach function. */
 +struct IOVATreeAllocArgs {
 +    /* Size of the desired allocation */
 +    size_t new_size;
 +
 +    /* The minimum address allowed in the allocation */
 +    hwaddr iova_begin;
 +
 +    /* Map at the left of the hole, can be NULL if "this" is first one */
 +    const DMAMap *prev;
 +
 +    /* Map at the right of the hole, can be NULL if "prev" is the last one */
 +    const DMAMap *this;
 +
 +    /* If found, we fill in the IOVA here */
 +    hwaddr iova_result;
 +
 +    /* Whether have we found a valid IOVA */
 +    bool iova_found;
 +};
 +
 +/**
 + * Iterate args to the next hole
 + *
 + * @args: The alloc arguments
 + * @next: The next mapping in the tree. Can be NULL to signal the last one
 + */
 +static void iova_tree_alloc_args_iterate(struct IOVATreeAllocArgs *args,
 +                                         const DMAMap *next) {
 +    args->prev = args->this;
 +    args->this = next;
 +}
 +
  static int iova_tree_compare(gconstpointer a, gconstpointer b, gpointer data)
  {
      const DMAMap *m1 = a, *m2 = b;
@@ -XXX,XX +XXX,XX @@ int iova_tree_remove(IOVATree *tree, const DMAMap *map)
      return IOVA_OK;
  }
 +/**
 + * Try to find an unallocated IOVA range between prev and this elements.
 + *
 + * @args: Arguments to allocation
 + *
 + * Cases:
 + *
 + * (1) !prev, !this: No entries allocated, always succeed
 + *
 + * (2) !prev, this: We're iterating at the 1st element.
 + *
 + * (3) prev, !this: We're iterating at the last element.
 + *
 + * (4) prev, this: this is the most common case, we'll try to find a hole
 + * between "prev" and "this" mapping.
 + *
 + * Note that this function assumes the last valid iova is HWADDR_MAX, but it
 + * searches linearly so it's easy to discard the result if it's not the case.
 + */
 +static void iova_tree_alloc_map_in_hole(struct IOVATreeAllocArgs *args)
 +{
 +    const DMAMap *prev = args->prev, *this = args->this;
 +    uint64_t hole_start, hole_last;
 +
 +    if (this && this->iova + this->size < args->iova_begin) {
 +        return;
 +    }
 +
 +    hole_start = MAX(prev ? prev->iova + prev->size + 1 : 0, args->iova_begin);
 +    hole_last = this ? this->iova : HWADDR_MAX;
 +
 +    if (hole_last - hole_start > args->new_size) {
 +        args->iova_result = hole_start;
 +        args->iova_found = true;
 +    }
 +}
 +
 +/**
 + * Foreach dma node in the tree, compare if there is a hole with its previous
 + * node (or minimum iova address allowed) and the node.
 + *
 + * @key: Node iterating
 + * @value: Node iterating
 + * @pargs: Struct to communicate with the outside world
 + *
 + * Return: false to keep iterating, true if needs break.
 + */
 +static gboolean iova_tree_alloc_traverse(gpointer key, gpointer value,
 +                                         gpointer pargs)
 +{
 +    struct IOVATreeAllocArgs *args = pargs;
 +    DMAMap *node = value;
 +
 +    assert(key == value);
 +
 +    iova_tree_alloc_args_iterate(args, node);
 +    iova_tree_alloc_map_in_hole(args);
 +    return args->iova_found;
 +}
 +
 +int iova_tree_alloc_map(IOVATree *tree, DMAMap *map, hwaddr iova_begin,
 +                        hwaddr iova_last)
 +{
 +    struct IOVATreeAllocArgs args = {
 +        .new_size = map->size,
 +        .iova_begin = iova_begin,
 +    };
 +
 +    if (unlikely(iova_last < iova_begin)) {
 +        return IOVA_ERR_INVALID;
 +    }
 +
 +    /*
 +     * Find a valid hole for the mapping
 +     *
 +     * Assuming low iova_begin, so no need to do a binary search to
 +     * locate the first node.
 +     *
 +     * TODO: Replace all this with g_tree_node_first/next/last when available
 +     * (from glib since 2.68). To do it with g_tree_foreach complicates the
 +     * code a lot.
 +     *
 +     */
 +    g_tree_foreach(tree->tree, iova_tree_alloc_traverse, &args);
 +    if (!args.iova_found) {
 +        /*
 +         * Either tree is empty or the last hole is still not checked.
 +         * g_tree_foreach does not compare (last, iova_last] range, so we check
 +         * it here.
 +         */
 +        iova_tree_alloc_args_iterate(&args, NULL);
 +        iova_tree_alloc_map_in_hole(&args);
 +    }
 +
 +    if (!args.iova_found || args.iova_result + map->size > iova_last) {
 +        return IOVA_ERR_NOMEM;
 +    }
 +
 +    map->iova = args.iova_result;
 +    return iova_tree_insert(tree, map);
 +}
 +
  void iova_tree_destroy(IOVATree *tree)
  {
      g_tree_destroy(tree->tree);
 --
 .7.4

-New patch
+[PULL V2 10/15] util: add iova_tree_find_iova
+From: Eugenio Pérez <eperezma@redhat.com>
+This function does the reverse operation of iova_tree_find: To look for
+a mapping that match a translated address so we can do the reverse.
+This have linear complexity instead of logarithmic, but it supports
+overlapping HVA. Future developments could reduce it.
+Acked-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+---
+ include/qemu/iova-tree.h | 20 +++++++++++++++++++-
+ util/iova-tree.c         | 34 ++++++++++++++++++++++++++++++++++
+files changed, 53 insertions(+), 1 deletion(-)
+diff --git a/include/qemu/iova-tree.h b/include/qemu/iova-tree.h
+index XXXXXXX..XXXXXXX 100644
+--- a/include/qemu/iova-tree.h
++++ b/include/qemu/iova-tree.h
+@@ -XXX,XX +XXX,XX @@ int iova_tree_remove(IOVATree *tree, const DMAMap *map);
+  * @tree: the iova tree to search from
+  * @map: the mapping to search
+  *
+- * Search for a mapping in the iova tree that overlaps with the
++ * Search for a mapping in the iova tree that iova overlaps with the
+  * mapping range specified.  Only the first found mapping will be
+  * returned.
+  *
+@@ -XXX,XX +XXX,XX @@ int iova_tree_remove(IOVATree *tree, const DMAMap *map);
+ const DMAMap *iova_tree_find(const IOVATree *tree, const DMAMap *map);
+ /**
++ * iova_tree_find_iova:
++ *
++ * @tree: the iova tree to search from
++ * @map: the mapping to search
++ *
++ * Search for a mapping in the iova tree that translated_addr overlaps with the
++ * mapping range specified.  Only the first found mapping will be
++ * returned.
++ *
++ * Return: DMAMap pointer if found, or NULL if not found.  Note that
++ * the returned DMAMap pointer is maintained internally.  User should
++ * only read the content but never modify or free the content.  Also,
++ * user is responsible to make sure the pointer is valid (say, no
++ * concurrent deletion in progress).
++ */
++const DMAMap *iova_tree_find_iova(const IOVATree *tree, const DMAMap *map);
++
++/**
+  * iova_tree_find_address:
+  *
+  * @tree: the iova tree to search from
+diff --git a/util/iova-tree.c b/util/iova-tree.c
+index XXXXXXX..XXXXXXX 100644
+--- a/util/iova-tree.c
++++ b/util/iova-tree.c
+@@ -XXX,XX +XXX,XX @@ struct IOVATreeAllocArgs {
+     bool iova_found;
+ };
++typedef struct IOVATreeFindIOVAArgs {
++    const DMAMap *needle;
++    const DMAMap *result;
++} IOVATreeFindIOVAArgs;
++
+ /**
+  * Iterate args to the next hole
+  *
+@@ -XXX,XX +XXX,XX @@ const DMAMap *iova_tree_find(const IOVATree *tree, const DMAMap *map)
+     return g_tree_lookup(tree->tree, map);
+ }
++static gboolean iova_tree_find_address_iterator(gpointer key, gpointer value,
++                                                gpointer data)
++{
++    const DMAMap *map = key;
++    IOVATreeFindIOVAArgs *args = data;
++    const DMAMap *needle;
++
++    g_assert(key == value);
++
++    needle = args->needle;
++    if (map->translated_addr + map->size < needle->translated_addr ||
++        needle->translated_addr + needle->size < map->translated_addr) {
++        return false;
++    }
++
++    args->result = map;
++    return true;
++}
++
++const DMAMap *iova_tree_find_iova(const IOVATree *tree, const DMAMap *map)
++{
++    IOVATreeFindIOVAArgs args = {
++        .needle = map,
++    };
++
++    g_tree_foreach(tree->tree, iova_tree_find_address_iterator, &args);
++    return args.result;
++}
++
+ const DMAMap *iova_tree_find_address(const IOVATree *tree, hwaddr iova)
+ {
+     const DMAMap map = { .iova = iova, .size = 0 };
+--
+.7.4

-New patch
+[PULL V2 11/15] vhost: Add VhostIOVATree
+From: Eugenio Pérez <eperezma@redhat.com>
+This tree is able to look for a translated address from an IOVA address.
+At first glance it is similar to util/iova-tree. However, SVQ working on
+devices with limited IOVA space need more capabilities, like allocating
+IOVA chunks or performing reverse translations (qemu addresses to iova).
+The allocation capability, as "assign a free IOVA address to this chunk
+of memory in qemu's address space" allows shadow virtqueue to create a
+new address space that is not restricted by guest's addressable one, so
+we can allocate shadow vqs vrings outside of it.
+It duplicates the tree so it can search efficiently in both directions,
+and it will signal overlap if iova or the translated address is present
+in any tree.
+Acked-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+---
+ hw/virtio/meson.build       |   2 +-
+ hw/virtio/vhost-iova-tree.c | 110 ++++++++++++++++++++++++++++++++++++++++++++
+ hw/virtio/vhost-iova-tree.h |  27 +++++++++++
+files changed, 138 insertions(+), 1 deletion(-)
+ create mode 100644 hw/virtio/vhost-iova-tree.c
+ create mode 100644 hw/virtio/vhost-iova-tree.h
+diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/virtio/meson.build
++++ b/hw/virtio/meson.build
+@@ -XXX,XX +XXX,XX @@ softmmu_ss.add(when: 'CONFIG_ALL', if_true: files('vhost-stub.c'))
+ virtio_ss = ss.source_set()
+ virtio_ss.add(files('virtio.c'))
+-virtio_ss.add(when: 'CONFIG_VHOST', if_true: files('vhost.c', 'vhost-backend.c', 'vhost-shadow-virtqueue.c'))
++virtio_ss.add(when: 'CONFIG_VHOST', if_true: files('vhost.c', 'vhost-backend.c', 'vhost-shadow-virtqueue.c', 'vhost-iova-tree.c'))
+ virtio_ss.add(when: 'CONFIG_VHOST_USER', if_true: files('vhost-user.c'))
+ virtio_ss.add(when: 'CONFIG_VHOST_VDPA', if_true: files('vhost-vdpa.c'))
+ virtio_ss.add(when: 'CONFIG_VIRTIO_BALLOON', if_true: files('virtio-balloon.c'))
+diff --git a/hw/virtio/vhost-iova-tree.c b/hw/virtio/vhost-iova-tree.c
+new file mode 100644
+index XXXXXXX..XXXXXXX
+--- /dev/null
++++ b/hw/virtio/vhost-iova-tree.c
+@@ -XXX,XX +XXX,XX @@
++/*
++ * vhost software live migration iova tree
++ *
++ * SPDX-FileCopyrightText: Red Hat, Inc. 2021
++ * SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
++ *
++ * SPDX-License-Identifier: GPL-2.0-or-later
++ */
++
++#include "qemu/osdep.h"
++#include "qemu/iova-tree.h"
++#include "vhost-iova-tree.h"
++
++#define iova_min_addr qemu_real_host_page_size
++
++/**
++ * VhostIOVATree, able to:
++ * - Translate iova address
++ * - Reverse translate iova address (from translated to iova)
++ * - Allocate IOVA regions for translated range (linear operation)
++ */
++struct VhostIOVATree {
++    /* First addressable iova address in the device */
++    uint64_t iova_first;
++
++    /* Last addressable iova address in the device */
++    uint64_t iova_last;
++
++    /* IOVA address to qemu memory maps. */
++    IOVATree *iova_taddr_map;
++};
++
++/**
++ * Create a new IOVA tree
++ *
++ * Returns the new IOVA tree
++ */
++VhostIOVATree *vhost_iova_tree_new(hwaddr iova_first, hwaddr iova_last)
++{
++    VhostIOVATree *tree = g_new(VhostIOVATree, 1);
++
++    /* Some devices do not like 0 addresses */
++    tree->iova_first = MAX(iova_first, iova_min_addr);
++    tree->iova_last = iova_last;
++
++    tree->iova_taddr_map = iova_tree_new();
++    return tree;
++}
++
++/**
++ * Delete an iova tree
++ */
++void vhost_iova_tree_delete(VhostIOVATree *iova_tree)
++{
++    iova_tree_destroy(iova_tree->iova_taddr_map);
++    g_free(iova_tree);
++}
++
++/**
++ * Find the IOVA address stored from a memory address
++ *
++ * @tree: The iova tree
++ * @map: The map with the memory address
++ *
++ * Return the stored mapping, or NULL if not found.
++ */
++const DMAMap *vhost_iova_tree_find_iova(const VhostIOVATree *tree,
++                                        const DMAMap *map)
++{
++    return iova_tree_find_iova(tree->iova_taddr_map, map);
++}
++
++/**
++ * Allocate a new mapping
++ *
++ * @tree: The iova tree
++ * @map: The iova map
++ *
++ * Returns:
++ * - IOVA_OK if the map fits in the container
++ * - IOVA_ERR_INVALID if the map does not make sense (like size overflow)
++ * - IOVA_ERR_NOMEM if tree cannot allocate more space.
++ *
++ * It returns assignated iova in map->iova if return value is VHOST_DMA_MAP_OK.
++ */
++int vhost_iova_tree_map_alloc(VhostIOVATree *tree, DMAMap *map)
++{
++    /* Some vhost devices do not like addr 0. Skip first page */
++    hwaddr iova_first = tree->iova_first ?: qemu_real_host_page_size;
++
++    if (map->translated_addr + map->size < map->translated_addr ||
++        map->perm == IOMMU_NONE) {
++        return IOVA_ERR_INVALID;
++    }
++
++    /* Allocate a node in IOVA address */
++    return iova_tree_alloc_map(tree->iova_taddr_map, map, iova_first,
++                               tree->iova_last);
++}
++
++/**
++ * Remove existing mappings from iova tree
++ *
++ * @iova_tree: The vhost iova tree
++ * @map: The map to remove
++ */
++void vhost_iova_tree_remove(VhostIOVATree *iova_tree, const DMAMap *map)
++{
++    iova_tree_remove(iova_tree->iova_taddr_map, map);
++}
+diff --git a/hw/virtio/vhost-iova-tree.h b/hw/virtio/vhost-iova-tree.h
+new file mode 100644
+index XXXXXXX..XXXXXXX
+--- /dev/null
++++ b/hw/virtio/vhost-iova-tree.h
+@@ -XXX,XX +XXX,XX @@
++/*
++ * vhost software live migration iova tree
++ *
++ * SPDX-FileCopyrightText: Red Hat, Inc. 2021
++ * SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
++ *
++ * SPDX-License-Identifier: GPL-2.0-or-later
++ */
++
++#ifndef HW_VIRTIO_VHOST_IOVA_TREE_H
++#define HW_VIRTIO_VHOST_IOVA_TREE_H
++
++#include "qemu/iova-tree.h"
++#include "exec/memory.h"
++
++typedef struct VhostIOVATree VhostIOVATree;
++
++VhostIOVATree *vhost_iova_tree_new(uint64_t iova_first, uint64_t iova_last);
++void vhost_iova_tree_delete(VhostIOVATree *iova_tree);
++G_DEFINE_AUTOPTR_CLEANUP_FUNC(VhostIOVATree, vhost_iova_tree_delete);
++
++const DMAMap *vhost_iova_tree_find_iova(const VhostIOVATree *iova_tree,
++                                        const DMAMap *map);
++int vhost_iova_tree_map_alloc(VhostIOVATree *iova_tree, DMAMap *map);
++void vhost_iova_tree_remove(VhostIOVATree *iova_tree, const DMAMap *map);
++
++#endif
+--
+.7.4

-[PULL 2/2] virtio-net: fix use after unmap/free for sg
+[PULL V2 12/15] vdpa: Add custom IOTLB translations to SVQ
-When mergeable buffer is enabled, we try to set the num_buffers after
+From: Eugenio Pérez <eperezma@redhat.com>
-the virtqueue elem has been unmapped. This will lead several issues,
-E.g a use after free when the descriptor has an address which belongs
+Use translations added in VhostIOVATree in SVQ.
-to the non direct access region. In this case we use bounce buffer
-that is allocated during address_space_map() and freed during
+Only introduce usage here, not allocation and deallocation. As with
-address_space_unmap().
+previous patches, we use the dead code paths of shadow_vqs_enabled to
+avoid commiting too many changes at once. These are impossible to take
-Fixing this by storing the elems temporarily in an array and delay the
+at the moment.
-unmap after we set the the num_buffers.
+Acked-by: Michael S. Tsirkin <mst@redhat.com>
-This addresses CVE-2021-3748.
+Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
 Reported-by: Alexander Bulekov <alxndr@bu.edu>
 Fixes: fbe78f4f55c6 ("virtio-net support")
 Cc: qemu-stable@nongnu.org
 Signed-off-by: Jason Wang <jasowang@redhat.com>
 ---
- hw/net/virtio-net.c | 39 ++++++++++++++++++++++++++++++++-------
+ hw/virtio/vhost-shadow-virtqueue.c |  75 +++++++++++++++++++++--
-file changed, 32 insertions(+), 7 deletions(-)
+ hw/virtio/vhost-shadow-virtqueue.h |   6 +-
+ hw/virtio/vhost-vdpa.c             | 122 +++++++++++++++++++++++++++++++------
-diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
+ include/hw/virtio/vhost-vdpa.h     |   3 +
 files changed, 181 insertions(+), 25 deletions(-)
 diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
 index XXXXXXX..XXXXXXX 100644
---- a/hw/net/virtio-net.c
+--- a/hw/virtio/vhost-shadow-virtqueue.c
-+++ b/hw/net/virtio-net.c
++++ b/hw/virtio/vhost-shadow-virtqueue.c
-@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
+@@ -XXX,XX +XXX,XX @@ static uint16_t vhost_svq_available_slots(const VhostShadowVirtqueue *svq)
-     VirtIONet *n = qemu_get_nic_opaque(nc);
+     return svq->vring.num - (svq->shadow_avail_idx - svq->shadow_used_idx);
-     VirtIONetQueue *q = virtio_net_get_subqueue(nc);
+ }
-     VirtIODevice *vdev = VIRTIO_DEVICE(n);
-+    VirtQueueElement *elems[VIRTQUEUE_MAX_SIZE];
++/**
-+    size_t lens[VIRTQUEUE_MAX_SIZE];
++ * Translate addresses between the qemu's virtual address and the SVQ IOVA
-     struct iovec mhdr_sg[VIRTQUEUE_MAX_SIZE];
++ *
-     struct virtio_net_hdr_mrg_rxbuf mhdr;
++ * @svq: Shadow VirtQueue
-     unsigned mhdr_cnt = 0;
++ * @vaddr: Translated IOVA addresses
--    size_t offset, i, guest_offset;
++ * @iovec: Source qemu's VA addresses
-+    size_t offset, i, guest_offset, j;
++ * @num: Length of iovec and minimum length of vaddr
-+    ssize_t err;
++ */
++static bool vhost_svq_translate_addr(const VhostShadowVirtqueue *svq,
-     if (!virtio_net_can_receive(nc)) {
++                                     void **addrs, const struct iovec *iovec,
-         return -1;
++                                     size_t num)
-@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
++{
++    if (num == 0) {
-         total = 0;
++        return true;
++    }
-+        if (i == VIRTQUEUE_MAX_SIZE) {
++
-+            virtio_error(vdev, "virtio-net unexpected long buffer chain");
++    for (size_t i = 0; i < num; ++i) {
-+            err = size;
++        DMAMap needle = {
-+            goto err;
++            .translated_addr = (hwaddr)iovec[i].iov_base,
 +            .size = iovec[i].iov_len,
 +        };
 +        size_t off;
 +
 +        const DMAMap *map = vhost_iova_tree_find_iova(svq->iova_tree, &needle);
 +        /*
 +         * Map cannot be NULL since iova map contains all guest space and
 +         * qemu already has a physical address mapped
 +         */
 +        if (unlikely(!map)) {
 +            qemu_log_mask(LOG_GUEST_ERROR,
 +                          "Invalid address 0x%"HWADDR_PRIx" given by guest",
 +                          needle.translated_addr);
 +            return false;
 +        }
 +
-         elem = virtqueue_pop(q->rx_vq, sizeof(VirtQueueElement));
++        off = needle.translated_addr - map->translated_addr;
-         if (!elem) {
++        addrs[i] = (void *)(map->iova + off);
-             if (i) {
++
-@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
++        if (unlikely(int128_gt(int128_add(needle.translated_addr,
-                              n->guest_hdr_len, n->host_hdr_len,
++                                          iovec[i].iov_len),
-                              vdev->guest_features);
++                               map->translated_addr + map->size))) {
-             }
++            qemu_log_mask(LOG_GUEST_ERROR,
--            return -1;
++                          "Guest buffer expands over iova range");
-+            err = -1;
++            return false;
-+            goto err;
++        }
 +    }
 +
 +    return true;
 +}
 +
  static void vhost_vring_write_descs(VhostShadowVirtqueue *svq,
 +                                    void * const *sg,
                                      const struct iovec *iovec,
                                      size_t num, bool more_descs, bool write)
  {
@@ -XXX,XX +XXX,XX @@ static void vhost_vring_write_descs(VhostShadowVirtqueue *svq,
          } else {
              descs[i].flags = flags;
          }
+-        descs[i].addr = cpu_to_le64((hwaddr)iovec[n].iov_base);
-         if (elem->in_num < 1) {
++        descs[i].addr = cpu_to_le64((hwaddr)sg[n]);
-@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
+         descs[i].len = cpu_to_le32(iovec[n].iov_len);
-                          "virtio-net receive queue contains no in buffers");
-             virtqueue_detach_element(q->rx_vq, elem, 0);
+         last = i;
-             g_free(elem);
+@@ -XXX,XX +XXX,XX @@ static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
--            return -1;
+ {
-+            err = -1;
+     unsigned avail_idx;
-+            goto err;
+     vring_avail_t *avail = svq->vring.avail;
-         }
++    bool ok;
++    g_autofree void **sgs = g_new(void *, MAX(elem->out_num, elem->in_num));
-         sg = elem->in_sg;
-@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
+     *head = svq->free_head;
-         if (!n->mergeable_rx_bufs && offset < size) {
-             virtqueue_unpop(q->rx_vq, elem, total);
+@@ -XXX,XX +XXX,XX @@ static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
-             g_free(elem);
+         return false;
 -            return size;
 +            err = size;
 +            goto err;
          }
 -        /* signal other side */
 -        virtqueue_fill(q->rx_vq, elem, total, i++);
 -        g_free(elem);
 +        elems[i] = elem;
 +        lens[i] = total;
 +        i++;
      }
-     if (mhdr_cnt) {
+-    vhost_vring_write_descs(svq, elem->out_sg, elem->out_num,
-@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
++    ok = vhost_svq_translate_addr(svq, sgs, elem->out_sg, elem->out_num);
-                      &mhdr.num_buffers, sizeof mhdr.num_buffers);
++    if (unlikely(!ok)) {
 +        return false;
 +    }
 +    vhost_vring_write_descs(svq, sgs, elem->out_sg, elem->out_num,
                              elem->in_num > 0, false);
 -    vhost_vring_write_descs(svq, elem->in_sg, elem->in_num, false, true);
 +
 +
 +    ok = vhost_svq_translate_addr(svq, sgs, elem->in_sg, elem->in_num);
 +    if (unlikely(!ok)) {
 +        return false;
 +    }
 +
 +    vhost_vring_write_descs(svq, sgs, elem->in_sg, elem->in_num, false, true);
      /*
       * Put the entry in the available array (but don't update avail->idx until
@@ -XXX,XX +XXX,XX @@ void vhost_svq_stop(VhostShadowVirtqueue *svq)
   * Creates vhost shadow virtqueue, and instructs the vhost device to use the
   * shadow methods and file descriptors.
   *
 + * @iova_tree: Tree to perform descriptors translations
 + *
   * Returns the new virtqueue or NULL.
   *
   * In case of error, reason is reported through error_report.
   */
 -VhostShadowVirtqueue *vhost_svq_new(void)
 +VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree)
  {
      g_autofree VhostShadowVirtqueue *svq = g_new0(VhostShadowVirtqueue, 1);
      int r;
@@ -XXX,XX +XXX,XX @@ VhostShadowVirtqueue *vhost_svq_new(void)
      event_notifier_init_fd(&svq->svq_kick, VHOST_FILE_UNBIND);
      event_notifier_set_handler(&svq->hdev_call, vhost_svq_handle_call);
 +    svq->iova_tree = iova_tree;
      return g_steal_pointer(&svq);
  err_init_hdev_call:
 diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/virtio/vhost-shadow-virtqueue.h
 +++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -XXX,XX +XXX,XX @@
  #include "qemu/event_notifier.h"
  #include "hw/virtio/virtio.h"
  #include "standard-headers/linux/vhost_types.h"
 +#include "hw/virtio/vhost-iova-tree.h"
  /* Shadow virtqueue to relay notifications */
  typedef struct VhostShadowVirtqueue {
@@ -XXX,XX +XXX,XX @@ typedef struct VhostShadowVirtqueue {
      /* Virtio device */
      VirtIODevice *vdev;
 +    /* IOVA mapping */
 +    VhostIOVATree *iova_tree;
 +
      /* Map for use the guest's descriptors */
      VirtQueueElement **ring_id_maps;
@@ -XXX,XX +XXX,XX @@ void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
                       VirtQueue *vq);
  void vhost_svq_stop(VhostShadowVirtqueue *svq);
 -VhostShadowVirtqueue *vhost_svq_new(void);
 +VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree);
  void vhost_svq_free(gpointer vq);
  G_DEFINE_AUTOPTR_CLEANUP_FUNC(VhostShadowVirtqueue, vhost_svq_free);
 diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/virtio/vhost-vdpa.c
 +++ b/hw/virtio/vhost-vdpa.c
@@ -XXX,XX +XXX,XX @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener,
                                           vaddr, section->readonly);
      llsize = int128_sub(llend, int128_make64(iova));
 +    if (v->shadow_vqs_enabled) {
 +        DMAMap mem_region = {
 +            .translated_addr = (hwaddr)vaddr,
 +            .size = int128_get64(llsize) - 1,
 +            .perm = IOMMU_ACCESS_FLAG(true, section->readonly),
 +        };
 +
 +        int r = vhost_iova_tree_map_alloc(v->iova_tree, &mem_region);
 +        if (unlikely(r != IOVA_OK)) {
 +            error_report("Can't allocate a mapping (%d)", r);
 +            goto fail;
 +        }
 +
 +        iova = mem_region.iova;
 +    }
      vhost_vdpa_iotlb_batch_begin_once(v);
      ret = vhost_vdpa_dma_map(v, iova, int128_get64(llsize),
@@ -XXX,XX +XXX,XX @@ static void vhost_vdpa_listener_region_del(MemoryListener *listener,
      llsize = int128_sub(llend, int128_make64(iova));
 +    if (v->shadow_vqs_enabled) {
 +        const DMAMap *result;
 +        const void *vaddr = memory_region_get_ram_ptr(section->mr) +
 +            section->offset_within_region +
 +            (iova - section->offset_within_address_space);
 +        DMAMap mem_region = {
 +            .translated_addr = (hwaddr)vaddr,
 +            .size = int128_get64(llsize) - 1,
 +        };
 +
 +        result = vhost_iova_tree_find_iova(v->iova_tree, &mem_region);
 +        iova = result->iova;
 +        vhost_iova_tree_remove(v->iova_tree, &mem_region);
 +    }
      vhost_vdpa_iotlb_batch_begin_once(v);
      ret = vhost_vdpa_dma_unmap(v, iova, int128_get64(llsize));
      if (ret) {
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
      shadow_vqs = g_ptr_array_new_full(hdev->nvqs, vhost_svq_free);
      for (unsigned n = 0; n < hdev->nvqs; ++n) {
 -        g_autoptr(VhostShadowVirtqueue) svq = vhost_svq_new();
 +        g_autoptr(VhostShadowVirtqueue) svq = vhost_svq_new(v->iova_tree);
          if (unlikely(!svq)) {
              error_setg(errp, "Cannot create svq %u", n);
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_svq_set_fds(struct vhost_dev *dev,
  /**
   * Unmap a SVQ area in the device
   */
 -static bool vhost_vdpa_svq_unmap_ring(struct vhost_vdpa *v, hwaddr iova,
 -                                      hwaddr size)
 +static bool vhost_vdpa_svq_unmap_ring(struct vhost_vdpa *v,
 +                                      const DMAMap *needle)
  {
 +    const DMAMap *result = vhost_iova_tree_find_iova(v->iova_tree, needle);
 +    hwaddr size;
      int r;
 -    size = ROUND_UP(size, qemu_real_host_page_size);
 -    r = vhost_vdpa_dma_unmap(v, iova, size);
 +    if (unlikely(!result)) {
 +        error_report("Unable to find SVQ address to unmap");
 +        return false;
 +    }
 +
 +    size = ROUND_UP(result->size, qemu_real_host_page_size);
 +    r = vhost_vdpa_dma_unmap(v, result->iova, size);
      return r == 0;
  }
  static bool vhost_vdpa_svq_unmap_rings(struct vhost_dev *dev,
                                         const VhostShadowVirtqueue *svq)
  {
 +    DMAMap needle = {};
      struct vhost_vdpa *v = dev->opaque;
      struct vhost_vring_addr svq_addr;
 -    size_t device_size = vhost_svq_device_area_size(svq);
 -    size_t driver_size = vhost_svq_driver_area_size(svq);
      bool ok;
      vhost_svq_get_vring_addr(svq, &svq_addr);
 -    ok = vhost_vdpa_svq_unmap_ring(v, svq_addr.desc_user_addr, driver_size);
 +    needle.translated_addr = svq_addr.desc_user_addr;
 +    ok = vhost_vdpa_svq_unmap_ring(v, &needle);
      if (unlikely(!ok)) {
          return false;
      }
-+    for (j = 0; j < i; j++) {
+-    return vhost_vdpa_svq_unmap_ring(v, svq_addr.used_user_addr, device_size);
-+        /* signal other side */
++    needle.translated_addr = svq_addr.used_user_addr;
-+        virtqueue_fill(q->rx_vq, elems[j], lens[j], j);
++    return vhost_vdpa_svq_unmap_ring(v, &needle);
-+        g_free(elems[j]);
++}
-+    }
++
-+
++/**
-     virtqueue_flush(q->rx_vq, i);
++ * Map the SVQ area in the device
-     virtio_notify(vdev, q->rx_vq);
++ *
++ * @v: Vhost-vdpa device
-     return size;
++ * @needle: The area to search iova
-+
++ * @errorp: Error pointer
-+err:
++ */
-+    for (j = 0; j < i; j++) {
++static bool vhost_vdpa_svq_map_ring(struct vhost_vdpa *v, DMAMap *needle,
-+        g_free(elems[j]);
++                                    Error **errp)
-+    }
++{
-+
++    int r;
-+    return err;
++
 +    r = vhost_iova_tree_map_alloc(v->iova_tree, needle);
 +    if (unlikely(r != IOVA_OK)) {
 +        error_setg(errp, "Cannot allocate iova (%d)", r);
 +        return false;
 +    }
 +
 +    r = vhost_vdpa_dma_map(v, needle->iova, needle->size + 1,
 +                           (void *)needle->translated_addr,
 +                           needle->perm == IOMMU_RO);
 +    if (unlikely(r != 0)) {
 +        error_setg_errno(errp, -r, "Cannot map region to device");
 +        vhost_iova_tree_remove(v->iova_tree, needle);
 +    }
 +
 +    return r == 0;
  }
- static ssize_t virtio_net_do_receive(NetClientState *nc, const uint8_t *buf,
+ /**
@@ -XXX,XX +XXX,XX @@ static bool vhost_vdpa_svq_map_rings(struct vhost_dev *dev,
                                       struct vhost_vring_addr *addr,
                                       Error **errp)
  {
 +    DMAMap device_region, driver_region;
 +    struct vhost_vring_addr svq_addr;
      struct vhost_vdpa *v = dev->opaque;
      size_t device_size = vhost_svq_device_area_size(svq);
      size_t driver_size = vhost_svq_driver_area_size(svq);
 -    int r;
 +    size_t avail_offset;
 +    bool ok;
      ERRP_GUARD();
 -    vhost_svq_get_vring_addr(svq, addr);
 +    vhost_svq_get_vring_addr(svq, &svq_addr);
 -    r = vhost_vdpa_dma_map(v, addr->desc_user_addr, driver_size,
 -                           (void *)addr->desc_user_addr, true);
 -    if (unlikely(r != 0)) {
 -        error_setg_errno(errp, -r, "Cannot create vq driver region: ");
 +    driver_region = (DMAMap) {
 +        .translated_addr = svq_addr.desc_user_addr,
 +        .size = driver_size - 1,
 +        .perm = IOMMU_RO,
 +    };
 +    ok = vhost_vdpa_svq_map_ring(v, &driver_region, errp);
 +    if (unlikely(!ok)) {
 +        error_prepend(errp, "Cannot create vq driver region: ");
          return false;
      }
 +    addr->desc_user_addr = driver_region.iova;
 +    avail_offset = svq_addr.avail_user_addr - svq_addr.desc_user_addr;
 +    addr->avail_user_addr = driver_region.iova + avail_offset;
 -    r = vhost_vdpa_dma_map(v, addr->used_user_addr, device_size,
 -                           (void *)addr->used_user_addr, false);
 -    if (unlikely(r != 0)) {
 -        error_setg_errno(errp, -r, "Cannot create vq device region: ");
 +    device_region = (DMAMap) {
 +        .translated_addr = svq_addr.used_user_addr,
 +        .size = device_size - 1,
 +        .perm = IOMMU_RW,
 +    };
 +    ok = vhost_vdpa_svq_map_ring(v, &device_region, errp);
 +    if (unlikely(!ok)) {
 +        error_prepend(errp, "Cannot create vq device region: ");
 +        vhost_vdpa_svq_unmap_ring(v, &driver_region);
      }
 +    addr->used_user_addr = device_region.iova;
 -    return r == 0;
 +    return ok;
  }
  static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
 diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
 index XXXXXXX..XXXXXXX 100644
 --- a/include/hw/virtio/vhost-vdpa.h
 +++ b/include/hw/virtio/vhost-vdpa.h
@@ -XXX,XX +XXX,XX @@
  #include <gmodule.h>
 +#include "hw/virtio/vhost-iova-tree.h"
  #include "hw/virtio/virtio.h"
  #include "standard-headers/linux/vhost_types.h"
@@ -XXX,XX +XXX,XX @@ typedef struct vhost_vdpa {
      MemoryListener listener;
      struct vhost_vdpa_iova_range iova_range;
      bool shadow_vqs_enabled;
 +    /* IOVA mapping used by the Shadow Virtqueue */
 +    VhostIOVATree *iova_tree;
      GPtrArray *shadow_vqs;
      struct vhost_dev *dev;
      VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
 --
 .7.4

-New patch
+[PULL V2 13/15] vdpa: Adapt vhost_vdpa_get_vring_base to SVQ
+From: Eugenio Pérez <eperezma@redhat.com>
+This is needed to achieve migration, so the destination can restore its
+index.
+Setting base as last used idx, so destination will see as available all
+the entries that the device did not use, including the in-flight
+processing ones.
+This is ok for networking, but other kinds of devices might have
+problems with these retransmissions.
+Acked-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+---
+ hw/virtio/vhost-vdpa.c | 17 +++++++++++++++++
+file changed, 17 insertions(+)
+diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/virtio/vhost-vdpa.c
++++ b/hw/virtio/vhost-vdpa.c
+@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_base(struct vhost_dev *dev,
+ static int vhost_vdpa_get_vring_base(struct vhost_dev *dev,
+                                        struct vhost_vring_state *ring)
+ {
++    struct vhost_vdpa *v = dev->opaque;
+     int ret;
++    if (v->shadow_vqs_enabled) {
++        VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs,
++                                                      ring->index);
++
++        /*
++         * Setting base as last used idx, so destination will see as available
++         * all the entries that the device did not use, including the in-flight
++         * processing ones.
++         *
++         * TODO: This is ok for networking, but other kinds of devices might
++         * have problems with these retransmissions.
++         */
++        ring->num = svq->last_used_idx;
++        return 0;
++    }
++
+     ret = vhost_vdpa_call(dev, VHOST_GET_VRING_BASE, ring);
+     trace_vhost_vdpa_get_vring_base(dev, ring->index, ring->num);
+     return ret;
+--
+.7.4

-New patch
+[PULL V2 14/15] vdpa: Never set log_base addr if SVQ is enabled
+From: Eugenio Pérez <eperezma@redhat.com>
+Setting the log address would make the device start reporting invalid
+dirty memory because the SVQ vrings are located in qemu's memory.
+Acked-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+---
+ hw/virtio/vhost-vdpa.c | 3 ++-
+file changed, 2 insertions(+), 1 deletion(-)
+diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
+index XXXXXXX..XXXXXXX 100644
+--- a/hw/virtio/vhost-vdpa.c
++++ b/hw/virtio/vhost-vdpa.c
+@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
+ static int vhost_vdpa_set_log_base(struct vhost_dev *dev, uint64_t base,
+                                      struct vhost_log *log)
+ {
+-    if (vhost_vdpa_one_time_request(dev)) {
++    struct vhost_vdpa *v = dev->opaque;
++    if (v->shadow_vqs_enabled || vhost_vdpa_one_time_request(dev)) {
+         return 0;
+     }
+--
+.7.4

-[PULL 1/2] ebpf: only include in system emulators
+[PULL V2 15/15] vdpa: Expose VHOST_F_LOG_ALL on SVQ
-From: Paolo Bonzini <pbonzini@redhat.com>
+From: Eugenio Pérez <eperezma@redhat.com>
-eBPF files are being included in user emulators, which is useless and
+SVQ is able to log the dirty bits by itself, so let's use it to not
-also breaks compilation because ebpf/trace-events is only processed
+block migration.
 if a system emulator is included in the build.
-Resolves: https://gitlab.com/qemu-project/qemu/-/issues/566
+Also, ignore set and clear of VHOST_F_LOG_ALL on set_features if SVQ is
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+enabled. Even if the device supports it, the reports would be nonsense
 because SVQ memory is in the qemu region.
 The log region is still allocated. Future changes might skip that, but
 this series is already long enough.
 Acked-by: Michael S. Tsirkin <mst@redhat.com>
 Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
 Signed-off-by: Jason Wang <jasowang@redhat.com>
 ---
- ebpf/meson.build | 2 +-
+ hw/virtio/vhost-vdpa.c         | 39 +++++++++++++++++++++++++++++++++++----
-file changed, 1 insertion(+), 1 deletion(-)
+ include/hw/virtio/vhost-vdpa.h |  1 +
 files changed, 36 insertions(+), 4 deletions(-)
-diff --git a/ebpf/meson.build b/ebpf/meson.build
+diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
 index XXXXXXX..XXXXXXX 100644
---- a/ebpf/meson.build
+--- a/hw/virtio/vhost-vdpa.c
-+++ b/ebpf/meson.build
++++ b/hw/virtio/vhost-vdpa.c
-@@ -1 +1 @@
+@@ -XXX,XX +XXX,XX @@ static bool vhost_vdpa_one_time_request(struct vhost_dev *dev)
--common_ss.add(when: libbpf, if_true: files('ebpf_rss.c'), if_false: files('ebpf_rss-stub.c'))
+     return v->index != 0;
-+softmmu_ss.add(when: libbpf, if_true: files('ebpf_rss.c'), if_false: files('ebpf_rss-stub.c'))
+ }
 +static int vhost_vdpa_get_dev_features(struct vhost_dev *dev,
 +                                       uint64_t *features)
 +{
 +    int ret;
 +
 +    ret = vhost_vdpa_call(dev, VHOST_GET_FEATURES, features);
 +    trace_vhost_vdpa_get_features(dev, *features);
 +    return ret;
 +}
 +
  static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
                                 Error **errp)
  {
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
          return 0;
      }
 -    r = hdev->vhost_ops->vhost_get_features(hdev, &dev_features);
 +    r = vhost_vdpa_get_dev_features(hdev, &dev_features);
      if (r != 0) {
          error_setg_errno(errp, -r, "Can't get vdpa device features");
          return r;
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_mem_table(struct vhost_dev *dev,
  static int vhost_vdpa_set_features(struct vhost_dev *dev,
                                     uint64_t features)
  {
 +    struct vhost_vdpa *v = dev->opaque;
      int ret;
      if (vhost_vdpa_one_time_request(dev)) {
          return 0;
      }
 +    if (v->shadow_vqs_enabled) {
 +        if ((v->acked_features ^ features) == BIT_ULL(VHOST_F_LOG_ALL)) {
 +            /*
 +             * QEMU is just trying to enable or disable logging. SVQ handles
 +             * this sepparately, so no need to forward this.
 +             */
 +            v->acked_features = features;
 +            return 0;
 +        }
 +
 +        v->acked_features = features;
 +
 +        /* We must not ack _F_LOG if SVQ is enabled */
 +        features &= ~BIT_ULL(VHOST_F_LOG_ALL);
 +    }
 +
      trace_vhost_vdpa_set_features(dev, features);
      ret = vhost_vdpa_call(dev, VHOST_SET_FEATURES, &features);
      if (ret) {
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_call(struct vhost_dev *dev,
  static int vhost_vdpa_get_features(struct vhost_dev *dev,
                                       uint64_t *features)
  {
 -    int ret;
 +    struct vhost_vdpa *v = dev->opaque;
 +    int ret = vhost_vdpa_get_dev_features(dev, features);
 +
 +    if (ret == 0 && v->shadow_vqs_enabled) {
 +        /* Add SVQ logging capabilities */
 +        *features |= BIT_ULL(VHOST_F_LOG_ALL);
 +    }
 -    ret = vhost_vdpa_call(dev, VHOST_GET_FEATURES, features);
 -    trace_vhost_vdpa_get_features(dev, *features);
      return ret;
  }
 diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
 index XXXXXXX..XXXXXXX 100644
 --- a/include/hw/virtio/vhost-vdpa.h
 +++ b/include/hw/virtio/vhost-vdpa.h
@@ -XXX,XX +XXX,XX @@ typedef struct vhost_vdpa {
      bool iotlb_batch_begin_sent;
      MemoryListener listener;
      struct vhost_vdpa_iova_range iova_range;
 +    uint64_t acked_features;
      bool shadow_vqs_enabled;
      /* IOVA mapping used by the Shadow Virtqueue */
      VhostIOVATree *iova_tree;
 --
 .7.4

When mergeable buffer is enabled, we try to set the num_buffers after
the virtqueue elem has been unmapped. This will lead several issues,
E.g a use after free when the descriptor has an address which belongs
to the non direct access region. In this case we use bounce buffer
that is allocated during address_space_map() and freed during
address_space_unmap().

Fixing this by storing the elems temporarily in an array and delay the
unmap after we set the the num_buffers.

This addresses CVE-2021-3748.

Reported-by: Alexander Bulekov <alxndr@bu.edu>
Fixes: fbe78f4f55c6 ("virtio-net support")
Cc: qemu-stable@nongnu.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/net/virtio-net.c | 39 ++++++++++++++++++++++++++++++++-------
 1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
     VirtIONet *n = qemu_get_nic_opaque(nc);
     VirtIONetQueue *q = virtio_net_get_subqueue(nc);
     VirtIODevice *vdev = VIRTIO_DEVICE(n);
+    VirtQueueElement *elems[VIRTQUEUE_MAX_SIZE];
+    size_t lens[VIRTQUEUE_MAX_SIZE];
     struct iovec mhdr_sg[VIRTQUEUE_MAX_SIZE];
     struct virtio_net_hdr_mrg_rxbuf mhdr;
     unsigned mhdr_cnt = 0;
-    size_t offset, i, guest_offset;
+    size_t offset, i, guest_offset, j;
+    ssize_t err;
 
     if (!virtio_net_can_receive(nc)) {
         return -1;
@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
 
         total = 0;
 
+        if (i == VIRTQUEUE_MAX_SIZE) {
+            virtio_error(vdev, "virtio-net unexpected long buffer chain");
+            err = size;
+            goto err;
+        }
+
         elem = virtqueue_pop(q->rx_vq, sizeof(VirtQueueElement));
         if (!elem) {
             if (i) {
@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
                              n->guest_hdr_len, n->host_hdr_len,
                              vdev->guest_features);
             }
-            return -1;
+            err = -1;
+            goto err;
         }
 
         if (elem->in_num < 1) {
@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
                          "virtio-net receive queue contains no in buffers");
             virtqueue_detach_element(q->rx_vq, elem, 0);
             g_free(elem);
-            return -1;
+            err = -1;
+            goto err;
         }
 
         sg = elem->in_sg;
@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
         if (!n->mergeable_rx_bufs && offset < size) {
             virtqueue_unpop(q->rx_vq, elem, total);
             g_free(elem);
-            return size;
+            err = size;
+            goto err;
         }
 
-        /* signal other side */
-        virtqueue_fill(q->rx_vq, elem, total, i++);
-        g_free(elem);
+        elems[i] = elem;
+        lens[i] = total;
+        i++;
     }
 
     if (mhdr_cnt) {
@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
                      &mhdr.num_buffers, sizeof mhdr.num_buffers);
     }
 
+    for (j = 0; j < i; j++) {
+        /* signal other side */
+        virtqueue_fill(q->rx_vq, elems[j], lens[j], j);
+        g_free(elems[j]);
+    }
+
     virtqueue_flush(q->rx_vq, i);
     virtio_notify(vdev, q->rx_vq);
 
     return size;
+
+err:
+    for (j = 0; j < i; j++) {
+        g_free(elems[j]);
+    }
+
+    return err;
 }
 
 static ssize_t virtio_net_do_receive(NetClientState *nc, const uint8_t *buf,
-- 
2.7.4

The following changes since commit d9ccf33f9479201e5add8db0af68ca9ca8da358b:

Merge remote-tracking branch 'remotes/lvivier-gitlab/tags/linux-user-for-7.0-pull-request' into staging (2022-03-09 20:01:17 +0000)

are available in the git repository at:

https://github.com/jasowang/qemu.git tags/net-pull-request

for you to fetch changes up to eea40402ecf895ed345f8e8eb07dbb484f4542c5:

vdpa: Expose VHOST_F_LOG_ALL on SVQ (2022-03-10 10:26:32 +0800)

----------------------------------------------------------------

----------------------------------------------------------------
Eugenio Pérez (14):
      vhost: Add VhostShadowVirtqueue
      vhost: Add Shadow VirtQueue kick forwarding capabilities
      vhost: Add Shadow VirtQueue call forwarding capabilities
      vhost: Add vhost_svq_valid_features to shadow vq
      virtio: Add vhost_svq_get_vring_addr
      vdpa: adapt vhost_ops callbacks to svq
      vhost: Shadow virtqueue buffers forwarding
      util: Add iova_tree_alloc_map
      util: add iova_tree_find_iova
      vhost: Add VhostIOVATree
      vdpa: Add custom IOTLB translations to SVQ
      vdpa: Adapt vhost_vdpa_get_vring_base to SVQ
      vdpa: Never set log_base addr if SVQ is enabled
      vdpa: Expose VHOST_F_LOG_ALL on SVQ

Jason Wang (1):
      virtio-net: fix map leaking on error during receive

hw/net/virtio-net.c                |   1 +
 hw/virtio/meson.build              |   2 +-
 hw/virtio/vhost-iova-tree.c        | 110 +++++++
 hw/virtio/vhost-iova-tree.h        |  27 ++
 hw/virtio/vhost-shadow-virtqueue.c | 638 +++++++++++++++++++++++++++++++++++++
 hw/virtio/vhost-shadow-virtqueue.h |  87 +++++
 hw/virtio/vhost-vdpa.c             | 525 +++++++++++++++++++++++++++++-
 include/hw/virtio/vhost-vdpa.h     |   8 +
 include/qemu/iova-tree.h           |  38 ++-
 util/iova-tree.c                   | 169 ++++++++++
 10 files changed, 1588 insertions(+), 17 deletions(-)
 create mode 100644 hw/virtio/vhost-iova-tree.c
 create mode 100644 hw/virtio/vhost-iova-tree.h
 create mode 100644 hw/virtio/vhost-shadow-virtqueue.c
 create mode 100644 hw/virtio/vhost-shadow-virtqueue.h

Commit bedd7e93d0196 ("virtio-net: fix use after unmap/free for sg")
tries to fix the use after free of the sg by caching the virtqueue
elements in an array and unmap them at once after receiving the
packets, But it forgot to unmap the cached elements on error which
will lead to leaking of mapping and other unexpected results.

Fixing this by detaching the cached elements on error. This addresses
CVE-2022-26353.

Reported-by: Victor Tom <vv474172261@gmail.com>
Cc: qemu-stable@nongnu.org
Fixes: CVE-2022-26353
Fixes: bedd7e93d0196 ("virtio-net: fix use after unmap/free for sg")
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/net/virtio-net.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -XXX,XX +XXX,XX @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
 
 err:
     for (j = 0; j < i; j++) {
+        virtqueue_detach_element(q->rx_vq, elems[j], lens[j]);
         g_free(elems[j]);
     }
 
-- 
2.7.4

From: Eugenio Pérez <eperezma@redhat.com>

Vhost shadow virtqueue (SVQ) is an intermediate jump for virtqueue
notifications and buffers, allowing qemu to track them. While qemu is
forwarding the buffers and virtqueue changes, it is able to commit the
memory it's being dirtied, the same way regular qemu's VirtIO devices
do.

This commit only exposes basic SVQ allocation and free. Next patches of
the series add functionality like notifications and buffers forwarding.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/meson.build              |  2 +-
 hw/virtio/vhost-shadow-virtqueue.c | 62 ++++++++++++++++++++++++++++++++++++++
 hw/virtio/vhost-shadow-virtqueue.h | 28 +++++++++++++++++
 3 files changed, 91 insertions(+), 1 deletion(-)
 create mode 100644 hw/virtio/vhost-shadow-virtqueue.c
 create mode 100644 hw/virtio/vhost-shadow-virtqueue.h

diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/meson.build
+++ b/hw/virtio/meson.build
@@ -XXX,XX +XXX,XX @@ softmmu_ss.add(when: 'CONFIG_ALL', if_true: files('vhost-stub.c'))
 
 virtio_ss = ss.source_set()
 virtio_ss.add(files('virtio.c'))
-virtio_ss.add(when: 'CONFIG_VHOST', if_true: files('vhost.c', 'vhost-backend.c'))
+virtio_ss.add(when: 'CONFIG_VHOST', if_true: files('vhost.c', 'vhost-backend.c', 'vhost-shadow-virtqueue.c'))
 virtio_ss.add(when: 'CONFIG_VHOST_USER', if_true: files('vhost-user.c'))
 virtio_ss.add(when: 'CONFIG_VHOST_VDPA', if_true: files('vhost-vdpa.c'))
 virtio_ss.add(when: 'CONFIG_VIRTIO_BALLOON', if_true: files('virtio-balloon.c'))
diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * vhost shadow virtqueue
+ *
+ * SPDX-FileCopyrightText: Red Hat, Inc. 2021
+ * SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "hw/virtio/vhost-shadow-virtqueue.h"
+
+#include "qemu/error-report.h"
+
+/**
+ * Creates vhost shadow virtqueue, and instructs the vhost device to use the
+ * shadow methods and file descriptors.
+ *
+ * Returns the new virtqueue or NULL.
+ *
+ * In case of error, reason is reported through error_report.
+ */
+VhostShadowVirtqueue *vhost_svq_new(void)
+{
+    g_autofree VhostShadowVirtqueue *svq = g_new0(VhostShadowVirtqueue, 1);
+    int r;
+
+    r = event_notifier_init(&svq->hdev_kick, 0);
+    if (r != 0) {
+        error_report("Couldn't create kick event notifier: %s (%d)",
+                     g_strerror(errno), errno);
+        goto err_init_hdev_kick;
+    }
+
+    r = event_notifier_init(&svq->hdev_call, 0);
+    if (r != 0) {
+        error_report("Couldn't create call event notifier: %s (%d)",
+                     g_strerror(errno), errno);
+        goto err_init_hdev_call;
+    }
+
+    return g_steal_pointer(&svq);
+
+err_init_hdev_call:
+    event_notifier_cleanup(&svq->hdev_kick);
+
+err_init_hdev_kick:
+    return NULL;
+}
+
+/**
+ * Free the resources of the shadow virtqueue.
+ *
+ * @pvq: gpointer to SVQ so it can be used by autofree functions.
+ */
+void vhost_svq_free(gpointer pvq)
+{
+    VhostShadowVirtqueue *vq = pvq;
+    event_notifier_cleanup(&vq->hdev_kick);
+    event_notifier_cleanup(&vq->hdev_call);
+    g_free(vq);
+}
diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -XXX,XX +XXX,XX @@
+/*
+ * vhost shadow virtqueue
+ *
+ * SPDX-FileCopyrightText: Red Hat, Inc. 2021
+ * SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef VHOST_SHADOW_VIRTQUEUE_H
+#define VHOST_SHADOW_VIRTQUEUE_H
+
+#include "qemu/event_notifier.h"
+
+/* Shadow virtqueue to relay notifications */
+typedef struct VhostShadowVirtqueue {
+    /* Shadow kick notifier, sent to vhost */
+    EventNotifier hdev_kick;
+    /* Shadow call notifier, sent to vhost */
+    EventNotifier hdev_call;
+} VhostShadowVirtqueue;
+
+VhostShadowVirtqueue *vhost_svq_new(void);
+
+void vhost_svq_free(gpointer vq);
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(VhostShadowVirtqueue, vhost_svq_free);
+
+#endif
-- 
2.7.4

From: Eugenio Pérez <eperezma@redhat.com>

At this mode no buffer forwarding will be performed in SVQ mode: Qemu
will just forward the guest's kicks to the device.

Host memory notifiers regions are left out for simplicity, and they will
not be addressed in this series.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.c |  56 ++++++++++++++
 hw/virtio/vhost-shadow-virtqueue.h |  14 ++++
 hw/virtio/vhost-vdpa.c             | 145 ++++++++++++++++++++++++++++++++++++-
 include/hw/virtio/vhost-vdpa.h     |   4 +
 4 files changed, 217 insertions(+), 2 deletions(-)

From: Eugenio Pérez <eperezma@redhat.com>

This will make qemu aware of the device used buffers, allowing it to
write the guest memory with its contents if needed.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.c | 38 ++++++++++++++++++++++++++++++++++++++
 hw/virtio/vhost-shadow-virtqueue.h |  4 ++++
 hw/virtio/vhost-vdpa.c             | 31 +++++++++++++++++++++++++++++--
 3 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -XXX,XX +XXX,XX @@ static void vhost_handle_guest_kick(EventNotifier *n)
 }
 
 /**
+ * Forward vhost notifications
+ *
+ * @n: hdev call event notifier, the one that device set to notify svq.
+ */
+static void vhost_svq_handle_call(EventNotifier *n)
+{
+    VhostShadowVirtqueue *svq = container_of(n, VhostShadowVirtqueue,
+                                             hdev_call);
+    event_notifier_test_and_clear(n);
+    event_notifier_set(&svq->svq_call);
+}
+
+/**
+ * Set the call notifier for the SVQ to call the guest
+ *
+ * @svq: Shadow virtqueue
+ * @call_fd: call notifier
+ *
+ * Called on BQL context.
+ */
+void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd)
+{
+    if (call_fd == VHOST_FILE_UNBIND) {
+        /*
+         * Fail event_notifier_set if called handling device call.
+         *
+         * SVQ still needs device notifications, since it needs to keep
+         * forwarding used buffers even with the unbind.
+         */
+        memset(&svq->svq_call, 0, sizeof(svq->svq_call));
+    } else {
+        event_notifier_init_fd(&svq->svq_call, call_fd);
+    }
+}
+
+/**
  * Set a new file descriptor for the guest to kick the SVQ and notify for avail
  *
  * @svq: The svq
@@ -XXX,XX +XXX,XX @@ VhostShadowVirtqueue *vhost_svq_new(void)
     }
 
     event_notifier_init_fd(&svq->svq_kick, VHOST_FILE_UNBIND);
+    event_notifier_set_handler(&svq->hdev_call, vhost_svq_handle_call);
     return g_steal_pointer(&svq);
 
 err_init_hdev_call:
@@ -XXX,XX +XXX,XX @@ void vhost_svq_free(gpointer pvq)
     VhostShadowVirtqueue *vq = pvq;
     vhost_svq_stop(vq);
     event_notifier_cleanup(&vq->hdev_kick);
+    event_notifier_set_handler(&vq->hdev_call, NULL);
     event_notifier_cleanup(&vq->hdev_call);
     g_free(vq);
 }
diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -XXX,XX +XXX,XX @@ typedef struct VhostShadowVirtqueue {
      * So shadow virtqueue must not clean it, or we would lose VirtQueue one.
      */
     EventNotifier svq_kick;
+
+    /* Guest's call notifier, where the SVQ calls guest. */
+    EventNotifier svq_call;
 } VhostShadowVirtqueue;
 
 void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd);
+void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd);
 
 void vhost_svq_stop(VhostShadowVirtqueue *svq);
 
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_dev_kick(struct vhost_dev *dev,
     return vhost_vdpa_call(dev, VHOST_SET_VRING_KICK, file);
 }
 
+static int vhost_vdpa_set_vring_dev_call(struct vhost_dev *dev,
+                                         struct vhost_vring_file *file)
+{
+    trace_vhost_vdpa_set_vring_call(dev, file->index, file->fd);
+    return vhost_vdpa_call(dev, VHOST_SET_VRING_CALL, file);
+}
+
 /**
  * Set the shadow virtqueue descriptors to the device
  *
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_dev_kick(struct vhost_dev *dev,
  * @svq: The shadow virtqueue
  * @idx: The index of the virtqueue in the vhost device
  * @errp: Error
+ *
+ * Note that this function does not rewind kick file descriptor if cannot set
+ * call one.
  */
 static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
                                  VhostShadowVirtqueue *svq,
@@ -XXX,XX +XXX,XX @@ static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
     r = vhost_vdpa_set_vring_dev_kick(dev, &file);
     if (unlikely(r != 0)) {
         error_setg_errno(errp, -r, "Can't set device kick fd");
+        return false;
+    }
+
+    event_notifier = &svq->hdev_call;
+    file.fd = event_notifier_get_fd(event_notifier);
+    r = vhost_vdpa_set_vring_dev_call(dev, &file);
+    if (unlikely(r != 0)) {
+        error_setg_errno(errp, -r, "Can't set device call fd");
     }
 
     return r == 0;
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_kick(struct vhost_dev *dev,
 static int vhost_vdpa_set_vring_call(struct vhost_dev *dev,
                                        struct vhost_vring_file *file)
 {
-    trace_vhost_vdpa_set_vring_call(dev, file->index, file->fd);
-    return vhost_vdpa_call(dev, VHOST_SET_VRING_CALL, file);
+    struct vhost_vdpa *v = dev->opaque;
+
+    if (v->shadow_vqs_enabled) {
+        int vdpa_idx = file->index - dev->vq_index;
+        VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, vdpa_idx);
+
+        vhost_svq_set_svq_call_fd(svq, file->fd);
+        return 0;
+    } else {
+        return vhost_vdpa_set_vring_dev_call(dev, file);
+    }
 }
 
 static int vhost_vdpa_get_features(struct vhost_dev *dev,
-- 
2.7.4

From: Eugenio Pérez <eperezma@redhat.com>

This allows SVQ to negotiate features with the guest and the device. For
the device, SVQ is a driver. While this function bypasses all
non-transport features, it needs to disable the features that SVQ does
not support when forwarding buffers. This includes packed vq layout,
indirect descriptors or event idx.

Future changes can add support to offer more features to the guest,
since the use of VirtQueue gives this for free. This is left out at the
moment for simplicity.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.c | 44 ++++++++++++++++++++++++++++++++++++++
 hw/virtio/vhost-shadow-virtqueue.h |  2 ++
 hw/virtio/vhost-vdpa.c             | 15 +++++++++++++
 3 files changed, 61 insertions(+)

From: Eugenio Pérez <eperezma@redhat.com>

It reports the shadow virtqueue address from qemu virtual address space.

Since this will be different from the guest's vaddr, but the device can
access it, SVQ takes special care about its alignment & lack of garbage
data. It assumes that IOMMU will work in host_page_size ranges for that.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.c | 29 +++++++++++++++++++++++++++++
 hw/virtio/vhost-shadow-virtqueue.h |  9 +++++++++
 2 files changed, 38 insertions(+)

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -XXX,XX +XXX,XX @@ void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd)
 }
 
 /**
+ * Get the shadow vq vring address.
+ * @svq: Shadow virtqueue
+ * @addr: Destination to store address
+ */
+void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq,
+                              struct vhost_vring_addr *addr)
+{
+    addr->desc_user_addr = (uint64_t)svq->vring.desc;
+    addr->avail_user_addr = (uint64_t)svq->vring.avail;
+    addr->used_user_addr = (uint64_t)svq->vring.used;
+}
+
+size_t vhost_svq_driver_area_size(const VhostShadowVirtqueue *svq)
+{
+    size_t desc_size = sizeof(vring_desc_t) * svq->vring.num;
+    size_t avail_size = offsetof(vring_avail_t, ring) +
+                                             sizeof(uint16_t) * svq->vring.num;
+
+    return ROUND_UP(desc_size + avail_size, qemu_real_host_page_size);
+}
+
+size_t vhost_svq_device_area_size(const VhostShadowVirtqueue *svq)
+{
+    size_t used_size = offsetof(vring_used_t, ring) +
+                                    sizeof(vring_used_elem_t) * svq->vring.num;
+    return ROUND_UP(used_size, qemu_real_host_page_size);
+}
+
+/**
  * Set a new file descriptor for the guest to kick the SVQ and notify for avail
  *
  * @svq: The svq
diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -XXX,XX +XXX,XX @@
 #define VHOST_SHADOW_VIRTQUEUE_H
 
 #include "qemu/event_notifier.h"
+#include "hw/virtio/virtio.h"
+#include "standard-headers/linux/vhost_types.h"
 
 /* Shadow virtqueue to relay notifications */
 typedef struct VhostShadowVirtqueue {
+    /* Shadow vring */
+    struct vring vring;
+
     /* Shadow kick notifier, sent to vhost */
     EventNotifier hdev_kick;
     /* Shadow call notifier, sent to vhost */
@@ -XXX,XX +XXX,XX @@ bool vhost_svq_valid_features(uint64_t features, Error **errp);
 
 void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd);
 void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd);
+void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq,
+                              struct vhost_vring_addr *addr);
+size_t vhost_svq_driver_area_size(const VhostShadowVirtqueue *svq);
+size_t vhost_svq_device_area_size(const VhostShadowVirtqueue *svq);
 
 void vhost_svq_stop(VhostShadowVirtqueue *svq);
 
-- 
2.7.4

From: Eugenio Pérez <eperezma@redhat.com>

First half of the buffers forwarding part, preparing vhost-vdpa
callbacks to SVQ to offer it. QEMU cannot enable it at this moment, so
this is effectively dead code at the moment, but it helps to reduce
patch size.

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_get_config(struct vhost_dev *dev, uint8_t *config,
     return ret;
  }
 
+static int vhost_vdpa_set_dev_vring_base(struct vhost_dev *dev,
+                                         struct vhost_vring_state *ring)
+{
+    trace_vhost_vdpa_set_vring_base(dev, ring->index, ring->num);
+    return vhost_vdpa_call(dev, VHOST_SET_VRING_BASE, ring);
+}
+
 static int vhost_vdpa_set_vring_dev_kick(struct vhost_dev *dev,
                                          struct vhost_vring_file *file)
 {
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_dev_call(struct vhost_dev *dev,
     return vhost_vdpa_call(dev, VHOST_SET_VRING_CALL, file);
 }
 
+static int vhost_vdpa_set_vring_dev_addr(struct vhost_dev *dev,
+                                         struct vhost_vring_addr *addr)
+{
+    trace_vhost_vdpa_set_vring_addr(dev, addr->index, addr->flags,
+                                addr->desc_user_addr, addr->used_user_addr,
+                                addr->avail_user_addr,
+                                addr->log_guest_addr);
+
+    return vhost_vdpa_call(dev, VHOST_SET_VRING_ADDR, addr);
+
+}
+
 /**
  * Set the shadow virtqueue descriptors to the device
  *
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_log_base(struct vhost_dev *dev, uint64_t base,
 static int vhost_vdpa_set_vring_addr(struct vhost_dev *dev,
                                        struct vhost_vring_addr *addr)
 {
-    trace_vhost_vdpa_set_vring_addr(dev, addr->index, addr->flags,
-                                    addr->desc_user_addr, addr->used_user_addr,
-                                    addr->avail_user_addr,
-                                    addr->log_guest_addr);
-    return vhost_vdpa_call(dev, VHOST_SET_VRING_ADDR, addr);
+    struct vhost_vdpa *v = dev->opaque;
+
+    if (v->shadow_vqs_enabled) {
+        /*
+         * Device vring addr was set at device start. SVQ base is handled by
+         * VirtQueue code.
+         */
+        return 0;
+    }
+
+    return vhost_vdpa_set_vring_dev_addr(dev, addr);
 }
 
 static int vhost_vdpa_set_vring_num(struct vhost_dev *dev,
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_num(struct vhost_dev *dev,
 static int vhost_vdpa_set_vring_base(struct vhost_dev *dev,
                                        struct vhost_vring_state *ring)
 {
-    trace_vhost_vdpa_set_vring_base(dev, ring->index, ring->num);
-    return vhost_vdpa_call(dev, VHOST_SET_VRING_BASE, ring);
+    struct vhost_vdpa *v = dev->opaque;
+
+    if (v->shadow_vqs_enabled) {
+        /*
+         * Device vring base was set at device start. SVQ base is handled by
+         * VirtQueue code.
+         */
+        return 0;
+    }
+
+    return vhost_vdpa_set_dev_vring_base(dev, ring);
 }
 
 static int vhost_vdpa_get_vring_base(struct vhost_dev *dev,
-- 
2.7.4

From: Eugenio Pérez <eperezma@redhat.com>

Initial version of shadow virtqueue that actually forward buffers. There
is no iommu support at the moment, and that will be addressed in future
patches of this series. Since all vhost-vdpa devices use forced IOMMU,
this means that SVQ is not usable at this point of the series on any
device.

For simplicity it only supports modern devices, that expects vring
in little endian, with split ring and no event idx or indirect
descriptors. Support for them will not be added in this series.

It reuses the VirtQueue code for the device part. The driver part is
based on Linux's virtio_ring driver, but with stripped functionality
and optimizations so it's easier to review.

However, forwarding buffers have some particular pieces: One of the most
unexpected ones is that a guest's buffer can expand through more than
one descriptor in SVQ. While this is handled gracefully by qemu's
emulated virtio devices, it may cause unexpected SVQ queue full. This
patch also solves it by checking for this condition at both guest's
kicks and device's calls. The code may be more elegant in the future if
SVQ code runs in its own iocontext.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.c | 354 ++++++++++++++++++++++++++++++++++++-
 hw/virtio/vhost-shadow-virtqueue.h |  26 +++
 hw/virtio/vhost-vdpa.c             | 159 ++++++++++++++++-
 3 files changed, 527 insertions(+), 12 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -XXX,XX +XXX,XX @@
 #include "qemu/error-report.h"
 #include "qapi/error.h"
 #include "qemu/main-loop.h"
+#include "qemu/log.h"
+#include "qemu/memalign.h"
 #include "linux-headers/linux/vhost.h"
 
 /**
@@ -XXX,XX +XXX,XX @@ bool vhost_svq_valid_features(uint64_t features, Error **errp)
 }
 
 /**
- * Forward guest notifications.
+ * Number of descriptors that the SVQ can make available from the guest.
+ *
+ * @svq: The svq
+ */
+static uint16_t vhost_svq_available_slots(const VhostShadowVirtqueue *svq)
+{
+    return svq->vring.num - (svq->shadow_avail_idx - svq->shadow_used_idx);
+}
+
+static void vhost_vring_write_descs(VhostShadowVirtqueue *svq,
+                                    const struct iovec *iovec,
+                                    size_t num, bool more_descs, bool write)
+{
+    uint16_t i = svq->free_head, last = svq->free_head;
+    unsigned n;
+    uint16_t flags = write ? cpu_to_le16(VRING_DESC_F_WRITE) : 0;
+    vring_desc_t *descs = svq->vring.desc;
+
+    if (num == 0) {
+        return;
+    }
+
+    for (n = 0; n < num; n++) {
+        if (more_descs || (n + 1 < num)) {
+            descs[i].flags = flags | cpu_to_le16(VRING_DESC_F_NEXT);
+        } else {
+            descs[i].flags = flags;
+        }
+        descs[i].addr = cpu_to_le64((hwaddr)iovec[n].iov_base);
+        descs[i].len = cpu_to_le32(iovec[n].iov_len);
+
+        last = i;
+        i = cpu_to_le16(descs[i].next);
+    }
+
+    svq->free_head = le16_to_cpu(descs[last].next);
+}
+
+static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
+                                VirtQueueElement *elem,
+                                unsigned *head)
+{
+    unsigned avail_idx;
+    vring_avail_t *avail = svq->vring.avail;
+
+    *head = svq->free_head;
+
+    /* We need some descriptors here */
+    if (unlikely(!elem->out_num && !elem->in_num)) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+            "Guest provided element with no descriptors");
+        return false;
+    }
+
+    vhost_vring_write_descs(svq, elem->out_sg, elem->out_num,
+                            elem->in_num > 0, false);
+    vhost_vring_write_descs(svq, elem->in_sg, elem->in_num, false, true);
+
+    /*
+     * Put the entry in the available array (but don't update avail->idx until
+     * they do sync).
+     */
+    avail_idx = svq->shadow_avail_idx & (svq->vring.num - 1);
+    avail->ring[avail_idx] = cpu_to_le16(*head);
+    svq->shadow_avail_idx++;
+
+    /* Update the avail index after write the descriptor */
+    smp_wmb();
+    avail->idx = cpu_to_le16(svq->shadow_avail_idx);
+
+    return true;
+}
+
+static bool vhost_svq_add(VhostShadowVirtqueue *svq, VirtQueueElement *elem)
+{
+    unsigned qemu_head;
+    bool ok = vhost_svq_add_split(svq, elem, &qemu_head);
+    if (unlikely(!ok)) {
+        return false;
+    }
+
+    svq->ring_id_maps[qemu_head] = elem;
+    return true;
+}
+
+static void vhost_svq_kick(VhostShadowVirtqueue *svq)
+{
+    /*
+     * We need to expose the available array entries before checking the used
+     * flags
+     */
+    smp_mb();
+    if (svq->vring.used->flags & VRING_USED_F_NO_NOTIFY) {
+        return;
+    }
+
+    event_notifier_set(&svq->hdev_kick);
+}
+
+/**
+ * Forward available buffers.
+ *
+ * @svq: Shadow VirtQueue
+ *
+ * Note that this function does not guarantee that all guest's available
+ * buffers are available to the device in SVQ avail ring. The guest may have
+ * exposed a GPA / GIOVA contiguous buffer, but it may not be contiguous in
+ * qemu vaddr.
+ *
+ * If that happens, guest's kick notifications will be disabled until the
+ * device uses some buffers.
+ */
+static void vhost_handle_guest_kick(VhostShadowVirtqueue *svq)
+{
+    /* Clear event notifier */
+    event_notifier_test_and_clear(&svq->svq_kick);
+
+    /* Forward to the device as many available buffers as possible */
+    do {
+        virtio_queue_set_notification(svq->vq, false);
+
+        while (true) {
+            VirtQueueElement *elem;
+            bool ok;
+
+            if (svq->next_guest_avail_elem) {
+                elem = g_steal_pointer(&svq->next_guest_avail_elem);
+            } else {
+                elem = virtqueue_pop(svq->vq, sizeof(*elem));
+            }
+
+            if (!elem) {
+                break;
+            }
+
+            if (elem->out_num + elem->in_num >
+                vhost_svq_available_slots(svq)) {
+                /*
+                 * This condition is possible since a contiguous buffer in GPA
+                 * does not imply a contiguous buffer in qemu's VA
+                 * scatter-gather segments. If that happens, the buffer exposed
+                 * to the device needs to be a chain of descriptors at this
+                 * moment.
+                 *
+                 * SVQ cannot hold more available buffers if we are here:
+                 * queue the current guest descriptor and ignore further kicks
+                 * until some elements are used.
+                 */
+                svq->next_guest_avail_elem = elem;
+                return;
+            }
+
+            ok = vhost_svq_add(svq, elem);
+            if (unlikely(!ok)) {
+                /* VQ is broken, just return and ignore any other kicks */
+                return;
+            }
+            vhost_svq_kick(svq);
+        }
+
+        virtio_queue_set_notification(svq->vq, true);
+    } while (!virtio_queue_empty(svq->vq));
+}
+
+/**
+ * Handle guest's kick.
  *
  * @n: guest kick event notifier, the one that guest set to notify svq.
  */
-static void vhost_handle_guest_kick(EventNotifier *n)
+static void vhost_handle_guest_kick_notifier(EventNotifier *n)
 {
     VhostShadowVirtqueue *svq = container_of(n, VhostShadowVirtqueue,
                                              svq_kick);
     event_notifier_test_and_clear(n);
-    event_notifier_set(&svq->hdev_kick);
+    vhost_handle_guest_kick(svq);
+}
+
+static bool vhost_svq_more_used(VhostShadowVirtqueue *svq)
+{
+    if (svq->last_used_idx != svq->shadow_used_idx) {
+        return true;
+    }
+
+    svq->shadow_used_idx = cpu_to_le16(svq->vring.used->idx);
+
+    return svq->last_used_idx != svq->shadow_used_idx;
 }
 
 /**
- * Forward vhost notifications
+ * Enable vhost device calls after disable them.
+ *
+ * @svq: The svq
+ *
+ * It returns false if there are pending used buffers from the vhost device,
+ * avoiding the possible races between SVQ checking for more work and enabling
+ * callbacks. True if SVQ used vring has no more pending buffers.
+ */
+static bool vhost_svq_enable_notification(VhostShadowVirtqueue *svq)
+{
+    svq->vring.avail->flags &= ~cpu_to_le16(VRING_AVAIL_F_NO_INTERRUPT);
+    /* Make sure the flag is written before the read of used_idx */
+    smp_mb();
+    return !vhost_svq_more_used(svq);
+}
+
+static void vhost_svq_disable_notification(VhostShadowVirtqueue *svq)
+{
+    svq->vring.avail->flags |= cpu_to_le16(VRING_AVAIL_F_NO_INTERRUPT);
+}
+
+static VirtQueueElement *vhost_svq_get_buf(VhostShadowVirtqueue *svq,
+                                           uint32_t *len)
+{
+    vring_desc_t *descs = svq->vring.desc;
+    const vring_used_t *used = svq->vring.used;
+    vring_used_elem_t used_elem;
+    uint16_t last_used;
+
+    if (!vhost_svq_more_used(svq)) {
+        return NULL;
+    }
+
+    /* Only get used array entries after they have been exposed by dev */
+    smp_rmb();
+    last_used = svq->last_used_idx & (svq->vring.num - 1);
+    used_elem.id = le32_to_cpu(used->ring[last_used].id);
+    used_elem.len = le32_to_cpu(used->ring[last_used].len);
+
+    svq->last_used_idx++;
+    if (unlikely(used_elem.id >= svq->vring.num)) {
+        qemu_log_mask(LOG_GUEST_ERROR, "Device %s says index %u is used",
+                      svq->vdev->name, used_elem.id);
+        return NULL;
+    }
+
+    if (unlikely(!svq->ring_id_maps[used_elem.id])) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+            "Device %s says index %u is used, but it was not available",
+            svq->vdev->name, used_elem.id);
+        return NULL;
+    }
+
+    descs[used_elem.id].next = svq->free_head;
+    svq->free_head = used_elem.id;
+
+    *len = used_elem.len;
+    return g_steal_pointer(&svq->ring_id_maps[used_elem.id]);
+}
+
+static void vhost_svq_flush(VhostShadowVirtqueue *svq,
+                            bool check_for_avail_queue)
+{
+    VirtQueue *vq = svq->vq;
+
+    /* Forward as many used buffers as possible. */
+    do {
+        unsigned i = 0;
+
+        vhost_svq_disable_notification(svq);
+        while (true) {
+            uint32_t len;
+            g_autofree VirtQueueElement *elem = vhost_svq_get_buf(svq, &len);
+            if (!elem) {
+                break;
+            }
+
+            if (unlikely(i >= svq->vring.num)) {
+                qemu_log_mask(LOG_GUEST_ERROR,
+                         "More than %u used buffers obtained in a %u size SVQ",
+                         i, svq->vring.num);
+                virtqueue_fill(vq, elem, len, i);
+                virtqueue_flush(vq, i);
+                return;
+            }
+            virtqueue_fill(vq, elem, len, i++);
+        }
+
+        virtqueue_flush(vq, i);
+        event_notifier_set(&svq->svq_call);
+
+        if (check_for_avail_queue && svq->next_guest_avail_elem) {
+            /*
+             * Avail ring was full when vhost_svq_flush was called, so it's a
+             * good moment to make more descriptors available if possible.
+             */
+            vhost_handle_guest_kick(svq);
+        }
+    } while (!vhost_svq_enable_notification(svq));
+}
+
+/**
+ * Forward used buffers.
  *
  * @n: hdev call event notifier, the one that device set to notify svq.
+ *
+ * Note that we are not making any buffers available in the loop, there is no
+ * way that it runs more than virtqueue size times.
  */
 static void vhost_svq_handle_call(EventNotifier *n)
 {
     VhostShadowVirtqueue *svq = container_of(n, VhostShadowVirtqueue,
                                              hdev_call);
     event_notifier_test_and_clear(n);
-    event_notifier_set(&svq->svq_call);
+    vhost_svq_flush(svq, true);
 }
 
 /**
@@ -XXX,XX +XXX,XX @@ void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd)
     if (poll_start) {
         event_notifier_init_fd(svq_kick, svq_kick_fd);
         event_notifier_set(svq_kick);
-        event_notifier_set_handler(svq_kick, vhost_handle_guest_kick);
+        event_notifier_set_handler(svq_kick, vhost_handle_guest_kick_notifier);
+    }
+}
+
+/**
+ * Start the shadow virtqueue operation.
+ *
+ * @svq: Shadow Virtqueue
+ * @vdev: VirtIO device
+ * @vq: Virtqueue to shadow
+ */
+void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
+                     VirtQueue *vq)
+{
+    size_t desc_size, driver_size, device_size;
+
+    svq->next_guest_avail_elem = NULL;
+    svq->shadow_avail_idx = 0;
+    svq->shadow_used_idx = 0;
+    svq->last_used_idx = 0;
+    svq->vdev = vdev;
+    svq->vq = vq;
+
+    svq->vring.num = virtio_queue_get_num(vdev, virtio_get_queue_index(vq));
+    driver_size = vhost_svq_driver_area_size(svq);
+    device_size = vhost_svq_device_area_size(svq);
+    svq->vring.desc = qemu_memalign(qemu_real_host_page_size, driver_size);
+    desc_size = sizeof(vring_desc_t) * svq->vring.num;
+    svq->vring.avail = (void *)((char *)svq->vring.desc + desc_size);
+    memset(svq->vring.desc, 0, driver_size);
+    svq->vring.used = qemu_memalign(qemu_real_host_page_size, device_size);
+    memset(svq->vring.used, 0, device_size);
+    svq->ring_id_maps = g_new0(VirtQueueElement *, svq->vring.num);
+    for (unsigned i = 0; i < svq->vring.num - 1; i++) {
+        svq->vring.desc[i].next = cpu_to_le16(i + 1);
     }
 }
 
@@ -XXX,XX +XXX,XX @@ void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd)
 void vhost_svq_stop(VhostShadowVirtqueue *svq)
 {
     event_notifier_set_handler(&svq->svq_kick, NULL);
+    g_autofree VirtQueueElement *next_avail_elem = NULL;
+
+    if (!svq->vq) {
+        return;
+    }
+
+    /* Send all pending used descriptors to guest */
+    vhost_svq_flush(svq, false);
+
+    for (unsigned i = 0; i < svq->vring.num; ++i) {
+        g_autofree VirtQueueElement *elem = NULL;
+        elem = g_steal_pointer(&svq->ring_id_maps[i]);
+        if (elem) {
+            virtqueue_detach_element(svq->vq, elem, 0);
+        }
+    }
+
+    next_avail_elem = g_steal_pointer(&svq->next_guest_avail_elem);
+    if (next_avail_elem) {
+        virtqueue_detach_element(svq->vq, next_avail_elem, 0);
+    }
+    svq->vq = NULL;
+    g_free(svq->ring_id_maps);
+    qemu_vfree(svq->vring.desc);
+    qemu_vfree(svq->vring.used);
 }
 
 /**
diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -XXX,XX +XXX,XX @@ typedef struct VhostShadowVirtqueue {
 
     /* Guest's call notifier, where the SVQ calls guest. */
     EventNotifier svq_call;
+
+    /* Virtio queue shadowing */
+    VirtQueue *vq;
+
+    /* Virtio device */
+    VirtIODevice *vdev;
+
+    /* Map for use the guest's descriptors */
+    VirtQueueElement **ring_id_maps;
+
+    /* Next VirtQueue element that guest made available */
+    VirtQueueElement *next_guest_avail_elem;
+
+    /* Next head to expose to the device */
+    uint16_t shadow_avail_idx;
+
+    /* Next free descriptor */
+    uint16_t free_head;
+
+    /* Last seen used idx */
+    uint16_t shadow_used_idx;
+
+    /* Next head to consume from the device */
+    uint16_t last_used_idx;
 } VhostShadowVirtqueue;
 
 bool vhost_svq_valid_features(uint64_t features, Error **errp);
@@ -XXX,XX +XXX,XX @@ void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq,
 size_t vhost_svq_driver_area_size(const VhostShadowVirtqueue *svq);
 size_t vhost_svq_device_area_size(const VhostShadowVirtqueue *svq);
 
+void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
+                     VirtQueue *vq);
 void vhost_svq_stop(VhostShadowVirtqueue *svq);
 
 VhostShadowVirtqueue *vhost_svq_new(void);
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_dev_addr(struct vhost_dev *dev,
  * Note that this function does not rewind kick file descriptor if cannot set
  * call one.
  */
-static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
-                                 VhostShadowVirtqueue *svq,
-                                 unsigned idx,
-                                 Error **errp)
+static int vhost_vdpa_svq_set_fds(struct vhost_dev *dev,
+                                  VhostShadowVirtqueue *svq,
+                                  unsigned idx,
+                                  Error **errp)
 {
     struct vhost_vring_file file = {
         .index = dev->vq_index + idx,
@@ -XXX,XX +XXX,XX @@ static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
     r = vhost_vdpa_set_vring_dev_kick(dev, &file);
     if (unlikely(r != 0)) {
         error_setg_errno(errp, -r, "Can't set device kick fd");
-        return false;
+        return r;
     }
 
     event_notifier = &svq->hdev_call;
@@ -XXX,XX +XXX,XX @@ static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
         error_setg_errno(errp, -r, "Can't set device call fd");
     }
 
+    return r;
+}
+
+/**
+ * Unmap a SVQ area in the device
+ */
+static bool vhost_vdpa_svq_unmap_ring(struct vhost_vdpa *v, hwaddr iova,
+                                      hwaddr size)
+{
+    int r;
+
+    size = ROUND_UP(size, qemu_real_host_page_size);
+    r = vhost_vdpa_dma_unmap(v, iova, size);
+    return r == 0;
+}
+
+static bool vhost_vdpa_svq_unmap_rings(struct vhost_dev *dev,
+                                       const VhostShadowVirtqueue *svq)
+{
+    struct vhost_vdpa *v = dev->opaque;
+    struct vhost_vring_addr svq_addr;
+    size_t device_size = vhost_svq_device_area_size(svq);
+    size_t driver_size = vhost_svq_driver_area_size(svq);
+    bool ok;
+
+    vhost_svq_get_vring_addr(svq, &svq_addr);
+
+    ok = vhost_vdpa_svq_unmap_ring(v, svq_addr.desc_user_addr, driver_size);
+    if (unlikely(!ok)) {
+        return false;
+    }
+
+    return vhost_vdpa_svq_unmap_ring(v, svq_addr.used_user_addr, device_size);
+}
+
+/**
+ * Map the shadow virtqueue rings in the device
+ *
+ * @dev: The vhost device
+ * @svq: The shadow virtqueue
+ * @addr: Assigned IOVA addresses
+ * @errp: Error pointer
+ */
+static bool vhost_vdpa_svq_map_rings(struct vhost_dev *dev,
+                                     const VhostShadowVirtqueue *svq,
+                                     struct vhost_vring_addr *addr,
+                                     Error **errp)
+{
+    struct vhost_vdpa *v = dev->opaque;
+    size_t device_size = vhost_svq_device_area_size(svq);
+    size_t driver_size = vhost_svq_driver_area_size(svq);
+    int r;
+
+    ERRP_GUARD();
+    vhost_svq_get_vring_addr(svq, addr);
+
+    r = vhost_vdpa_dma_map(v, addr->desc_user_addr, driver_size,
+                           (void *)addr->desc_user_addr, true);
+    if (unlikely(r != 0)) {
+        error_setg_errno(errp, -r, "Cannot create vq driver region: ");
+        return false;
+    }
+
+    r = vhost_vdpa_dma_map(v, addr->used_user_addr, device_size,
+                           (void *)addr->used_user_addr, false);
+    if (unlikely(r != 0)) {
+        error_setg_errno(errp, -r, "Cannot create vq device region: ");
+    }
+
+    return r == 0;
+}
+
+static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
+                                 VhostShadowVirtqueue *svq,
+                                 unsigned idx,
+                                 Error **errp)
+{
+    uint16_t vq_index = dev->vq_index + idx;
+    struct vhost_vring_state s = {
+        .index = vq_index,
+    };
+    int r;
+
+    r = vhost_vdpa_set_dev_vring_base(dev, &s);
+    if (unlikely(r)) {
+        error_setg_errno(errp, -r, "Cannot set vring base");
+        return false;
+    }
+
+    r = vhost_vdpa_svq_set_fds(dev, svq, idx, errp);
     return r == 0;
 }
 
@@ -XXX,XX +XXX,XX @@ static bool vhost_vdpa_svqs_start(struct vhost_dev *dev)
     }
 
     for (i = 0; i < v->shadow_vqs->len; ++i) {
+        VirtQueue *vq = virtio_get_queue(dev->vdev, dev->vq_index + i);
         VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, i);
+        struct vhost_vring_addr addr = {
+            .index = i,
+        };
+        int r;
         bool ok = vhost_vdpa_svq_setup(dev, svq, i, &err);
         if (unlikely(!ok)) {
-            error_reportf_err(err, "Cannot setup SVQ %u: ", i);
+            goto err;
+        }
+
+        vhost_svq_start(svq, dev->vdev, vq);
+        ok = vhost_vdpa_svq_map_rings(dev, svq, &addr, &err);
+        if (unlikely(!ok)) {
+            goto err_map;
+        }
+
+        /* Override vring GPA set by vhost subsystem */
+        r = vhost_vdpa_set_vring_dev_addr(dev, &addr);
+        if (unlikely(r != 0)) {
+            error_setg_errno(&err, -r, "Cannot set device address");
+            goto err_set_addr;
+        }
+    }
+
+    return true;
+
+err_set_addr:
+    vhost_vdpa_svq_unmap_rings(dev, g_ptr_array_index(v->shadow_vqs, i));
+
+err_map:
+    vhost_svq_stop(g_ptr_array_index(v->shadow_vqs, i));
+
+err:
+    error_reportf_err(err, "Cannot setup SVQ %u: ", i);
+    for (unsigned j = 0; j < i; ++j) {
+        VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, j);
+        vhost_vdpa_svq_unmap_rings(dev, svq);
+        vhost_svq_stop(svq);
+    }
+
+    return false;
+}
+
+static bool vhost_vdpa_svqs_stop(struct vhost_dev *dev)
+{
+    struct vhost_vdpa *v = dev->opaque;
+
+    if (!v->shadow_vqs) {
+        return true;
+    }
+
+    for (unsigned i = 0; i < v->shadow_vqs->len; ++i) {
+        VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs,
+                                                      i);
+        bool ok = vhost_vdpa_svq_unmap_rings(dev, svq);
+        if (unlikely(!ok)) {
             return false;
         }
     }
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
         }
         vhost_vdpa_set_vring_ready(dev);
     } else {
+        ok = vhost_vdpa_svqs_stop(dev);
+        if (unlikely(!ok)) {
+            return -1;
+        }
         vhost_vdpa_host_notifiers_uninit(dev, dev->nvqs);
     }
 
-- 
2.7.4

From: Eugenio Pérez <eperezma@redhat.com>

This iova tree function allows it to look for a hole in allocated
regions and return a totally new translation for a given translated
address.

It's usage is mainly to allow devices to access qemu address space,
remapping guest's one into a new iova space where qemu can add chunks of
addresses.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 include/qemu/iova-tree.h |  18 +++++++
 util/iova-tree.c         | 135 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 153 insertions(+)

diff --git a/include/qemu/iova-tree.h b/include/qemu/iova-tree.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/iova-tree.h
+++ b/include/qemu/iova-tree.h
@@ -XXX,XX +XXX,XX @@
 #define  IOVA_OK           (0)
 #define  IOVA_ERR_INVALID  (-1) /* Invalid parameters */
 #define  IOVA_ERR_OVERLAP  (-2) /* IOVA range overlapped */
+#define  IOVA_ERR_NOMEM    (-3) /* Cannot allocate */
 
 typedef struct IOVATree IOVATree;
 typedef struct DMAMap {
@@ -XXX,XX +XXX,XX @@ const DMAMap *iova_tree_find_address(const IOVATree *tree, hwaddr iova);
 void iova_tree_foreach(IOVATree *tree, iova_tree_iterator iterator);
 
 /**
+ * iova_tree_alloc_map:
+ *
+ * @tree: the iova tree to allocate from
+ * @map: the new map (as translated addr & size) to allocate in the iova region
+ * @iova_begin: the minimum address of the allocation
+ * @iova_end: the maximum addressable direction of the allocation
+ *
+ * Allocates a new region of a given size, between iova_min and iova_max.
+ *
+ * Return: Same as iova_tree_insert, but cannot overlap and can return error if
+ * iova tree is out of free contiguous range. The caller gets the assigned iova
+ * in map->iova.
+ */
+int iova_tree_alloc_map(IOVATree *tree, DMAMap *map, hwaddr iova_begin,
+                        hwaddr iova_end);
+
+/**
  * iova_tree_destroy:
  *
  * @tree: the iova tree to destroy
diff --git a/util/iova-tree.c b/util/iova-tree.c
index XXXXXXX..XXXXXXX 100644
--- a/util/iova-tree.c
+++ b/util/iova-tree.c
@@ -XXX,XX +XXX,XX @@ struct IOVATree {
     GTree *tree;
 };
 
+/* Args to pass to iova_tree_alloc foreach function. */
+struct IOVATreeAllocArgs {
+    /* Size of the desired allocation */
+    size_t new_size;
+
+    /* The minimum address allowed in the allocation */
+    hwaddr iova_begin;
+
+    /* Map at the left of the hole, can be NULL if "this" is first one */
+    const DMAMap *prev;
+
+    /* Map at the right of the hole, can be NULL if "prev" is the last one */
+    const DMAMap *this;
+
+    /* If found, we fill in the IOVA here */
+    hwaddr iova_result;
+
+    /* Whether have we found a valid IOVA */
+    bool iova_found;
+};
+
+/**
+ * Iterate args to the next hole
+ *
+ * @args: The alloc arguments
+ * @next: The next mapping in the tree. Can be NULL to signal the last one
+ */
+static void iova_tree_alloc_args_iterate(struct IOVATreeAllocArgs *args,
+                                         const DMAMap *next) {
+    args->prev = args->this;
+    args->this = next;
+}
+
 static int iova_tree_compare(gconstpointer a, gconstpointer b, gpointer data)
 {
     const DMAMap *m1 = a, *m2 = b;
@@ -XXX,XX +XXX,XX @@ int iova_tree_remove(IOVATree *tree, const DMAMap *map)
     return IOVA_OK;
 }
 
+/**
+ * Try to find an unallocated IOVA range between prev and this elements.
+ *
+ * @args: Arguments to allocation
+ *
+ * Cases:
+ *
+ * (1) !prev, !this: No entries allocated, always succeed
+ *
+ * (2) !prev, this: We're iterating at the 1st element.
+ *
+ * (3) prev, !this: We're iterating at the last element.
+ *
+ * (4) prev, this: this is the most common case, we'll try to find a hole
+ * between "prev" and "this" mapping.
+ *
+ * Note that this function assumes the last valid iova is HWADDR_MAX, but it
+ * searches linearly so it's easy to discard the result if it's not the case.
+ */
+static void iova_tree_alloc_map_in_hole(struct IOVATreeAllocArgs *args)
+{
+    const DMAMap *prev = args->prev, *this = args->this;
+    uint64_t hole_start, hole_last;
+
+    if (this && this->iova + this->size < args->iova_begin) {
+        return;
+    }
+
+    hole_start = MAX(prev ? prev->iova + prev->size + 1 : 0, args->iova_begin);
+    hole_last = this ? this->iova : HWADDR_MAX;
+
+    if (hole_last - hole_start > args->new_size) {
+        args->iova_result = hole_start;
+        args->iova_found = true;
+    }
+}
+
+/**
+ * Foreach dma node in the tree, compare if there is a hole with its previous
+ * node (or minimum iova address allowed) and the node.
+ *
+ * @key: Node iterating
+ * @value: Node iterating
+ * @pargs: Struct to communicate with the outside world
+ *
+ * Return: false to keep iterating, true if needs break.
+ */
+static gboolean iova_tree_alloc_traverse(gpointer key, gpointer value,
+                                         gpointer pargs)
+{
+    struct IOVATreeAllocArgs *args = pargs;
+    DMAMap *node = value;
+
+    assert(key == value);
+
+    iova_tree_alloc_args_iterate(args, node);
+    iova_tree_alloc_map_in_hole(args);
+    return args->iova_found;
+}
+
+int iova_tree_alloc_map(IOVATree *tree, DMAMap *map, hwaddr iova_begin,
+                        hwaddr iova_last)
+{
+    struct IOVATreeAllocArgs args = {
+        .new_size = map->size,
+        .iova_begin = iova_begin,
+    };
+
+    if (unlikely(iova_last < iova_begin)) {
+        return IOVA_ERR_INVALID;
+    }
+
+    /*
+     * Find a valid hole for the mapping
+     *
+     * Assuming low iova_begin, so no need to do a binary search to
+     * locate the first node.
+     *
+     * TODO: Replace all this with g_tree_node_first/next/last when available
+     * (from glib since 2.68). To do it with g_tree_foreach complicates the
+     * code a lot.
+     *
+     */
+    g_tree_foreach(tree->tree, iova_tree_alloc_traverse, &args);
+    if (!args.iova_found) {
+        /*
+         * Either tree is empty or the last hole is still not checked.
+         * g_tree_foreach does not compare (last, iova_last] range, so we check
+         * it here.
+         */
+        iova_tree_alloc_args_iterate(&args, NULL);
+        iova_tree_alloc_map_in_hole(&args);
+    }
+
+    if (!args.iova_found || args.iova_result + map->size > iova_last) {
+        return IOVA_ERR_NOMEM;
+    }
+
+    map->iova = args.iova_result;
+    return iova_tree_insert(tree, map);
+}
+
 void iova_tree_destroy(IOVATree *tree)
 {
     g_tree_destroy(tree->tree);
-- 
2.7.4

From: Eugenio Pérez <eperezma@redhat.com>

This function does the reverse operation of iova_tree_find: To look for
a mapping that match a translated address so we can do the reverse.

This have linear complexity instead of logarithmic, but it supports
overlapping HVA. Future developments could reduce it.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 include/qemu/iova-tree.h | 20 +++++++++++++++++++-
 util/iova-tree.c         | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/include/qemu/iova-tree.h b/include/qemu/iova-tree.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/iova-tree.h
+++ b/include/qemu/iova-tree.h
@@ -XXX,XX +XXX,XX @@ int iova_tree_remove(IOVATree *tree, const DMAMap *map);
  * @tree: the iova tree to search from
  * @map: the mapping to search
  *
- * Search for a mapping in the iova tree that overlaps with the
+ * Search for a mapping in the iova tree that iova overlaps with the
  * mapping range specified.  Only the first found mapping will be
  * returned.
  *
@@ -XXX,XX +XXX,XX @@ int iova_tree_remove(IOVATree *tree, const DMAMap *map);
 const DMAMap *iova_tree_find(const IOVATree *tree, const DMAMap *map);
 
 /**
+ * iova_tree_find_iova:
+ *
+ * @tree: the iova tree to search from
+ * @map: the mapping to search
+ *
+ * Search for a mapping in the iova tree that translated_addr overlaps with the
+ * mapping range specified.  Only the first found mapping will be
+ * returned.
+ *
+ * Return: DMAMap pointer if found, or NULL if not found.  Note that
+ * the returned DMAMap pointer is maintained internally.  User should
+ * only read the content but never modify or free the content.  Also,
+ * user is responsible to make sure the pointer is valid (say, no
+ * concurrent deletion in progress).
+ */
+const DMAMap *iova_tree_find_iova(const IOVATree *tree, const DMAMap *map);
+
+/**
  * iova_tree_find_address:
  *
  * @tree: the iova tree to search from
diff --git a/util/iova-tree.c b/util/iova-tree.c
index XXXXXXX..XXXXXXX 100644
--- a/util/iova-tree.c
+++ b/util/iova-tree.c
@@ -XXX,XX +XXX,XX @@ struct IOVATreeAllocArgs {
     bool iova_found;
 };
 
+typedef struct IOVATreeFindIOVAArgs {
+    const DMAMap *needle;
+    const DMAMap *result;
+} IOVATreeFindIOVAArgs;
+
 /**
  * Iterate args to the next hole
  *
@@ -XXX,XX +XXX,XX @@ const DMAMap *iova_tree_find(const IOVATree *tree, const DMAMap *map)
     return g_tree_lookup(tree->tree, map);
 }
 
+static gboolean iova_tree_find_address_iterator(gpointer key, gpointer value,
+                                                gpointer data)
+{
+    const DMAMap *map = key;
+    IOVATreeFindIOVAArgs *args = data;
+    const DMAMap *needle;
+
+    g_assert(key == value);
+
+    needle = args->needle;
+    if (map->translated_addr + map->size < needle->translated_addr ||
+        needle->translated_addr + needle->size < map->translated_addr) {
+        return false;
+    }
+
+    args->result = map;
+    return true;
+}
+
+const DMAMap *iova_tree_find_iova(const IOVATree *tree, const DMAMap *map)
+{
+    IOVATreeFindIOVAArgs args = {
+        .needle = map,
+    };
+
+    g_tree_foreach(tree->tree, iova_tree_find_address_iterator, &args);
+    return args.result;
+}
+
 const DMAMap *iova_tree_find_address(const IOVATree *tree, hwaddr iova)
 {
     const DMAMap map = { .iova = iova, .size = 0 };
-- 
2.7.4

From: Eugenio Pérez <eperezma@redhat.com>

This tree is able to look for a translated address from an IOVA address.

At first glance it is similar to util/iova-tree. However, SVQ working on
devices with limited IOVA space need more capabilities, like allocating
IOVA chunks or performing reverse translations (qemu addresses to iova).

The allocation capability, as "assign a free IOVA address to this chunk
of memory in qemu's address space" allows shadow virtqueue to create a
new address space that is not restricted by guest's addressable one, so
we can allocate shadow vqs vrings outside of it.

It duplicates the tree so it can search efficiently in both directions,
and it will signal overlap if iova or the translated address is present
in any tree.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/meson.build       |   2 +-
 hw/virtio/vhost-iova-tree.c | 110 ++++++++++++++++++++++++++++++++++++++++++++
 hw/virtio/vhost-iova-tree.h |  27 +++++++++++
 3 files changed, 138 insertions(+), 1 deletion(-)
 create mode 100644 hw/virtio/vhost-iova-tree.c
 create mode 100644 hw/virtio/vhost-iova-tree.h

diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/meson.build
+++ b/hw/virtio/meson.build
@@ -XXX,XX +XXX,XX @@ softmmu_ss.add(when: 'CONFIG_ALL', if_true: files('vhost-stub.c'))
 
 virtio_ss = ss.source_set()
 virtio_ss.add(files('virtio.c'))
-virtio_ss.add(when: 'CONFIG_VHOST', if_true: files('vhost.c', 'vhost-backend.c', 'vhost-shadow-virtqueue.c'))
+virtio_ss.add(when: 'CONFIG_VHOST', if_true: files('vhost.c', 'vhost-backend.c', 'vhost-shadow-virtqueue.c', 'vhost-iova-tree.c'))
 virtio_ss.add(when: 'CONFIG_VHOST_USER', if_true: files('vhost-user.c'))
 virtio_ss.add(when: 'CONFIG_VHOST_VDPA', if_true: files('vhost-vdpa.c'))
 virtio_ss.add(when: 'CONFIG_VIRTIO_BALLOON', if_true: files('virtio-balloon.c'))
diff --git a/hw/virtio/vhost-iova-tree.c b/hw/virtio/vhost-iova-tree.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/virtio/vhost-iova-tree.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * vhost software live migration iova tree
+ *
+ * SPDX-FileCopyrightText: Red Hat, Inc. 2021
+ * SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/iova-tree.h"
+#include "vhost-iova-tree.h"
+
+#define iova_min_addr qemu_real_host_page_size
+
+/**
+ * VhostIOVATree, able to:
+ * - Translate iova address
+ * - Reverse translate iova address (from translated to iova)
+ * - Allocate IOVA regions for translated range (linear operation)
+ */
+struct VhostIOVATree {
+    /* First addressable iova address in the device */
+    uint64_t iova_first;
+
+    /* Last addressable iova address in the device */
+    uint64_t iova_last;
+
+    /* IOVA address to qemu memory maps. */
+    IOVATree *iova_taddr_map;
+};
+
+/**
+ * Create a new IOVA tree
+ *
+ * Returns the new IOVA tree
+ */
+VhostIOVATree *vhost_iova_tree_new(hwaddr iova_first, hwaddr iova_last)
+{
+    VhostIOVATree *tree = g_new(VhostIOVATree, 1);
+
+    /* Some devices do not like 0 addresses */
+    tree->iova_first = MAX(iova_first, iova_min_addr);
+    tree->iova_last = iova_last;
+
+    tree->iova_taddr_map = iova_tree_new();
+    return tree;
+}
+
+/**
+ * Delete an iova tree
+ */
+void vhost_iova_tree_delete(VhostIOVATree *iova_tree)
+{
+    iova_tree_destroy(iova_tree->iova_taddr_map);
+    g_free(iova_tree);
+}
+
+/**
+ * Find the IOVA address stored from a memory address
+ *
+ * @tree: The iova tree
+ * @map: The map with the memory address
+ *
+ * Return the stored mapping, or NULL if not found.
+ */
+const DMAMap *vhost_iova_tree_find_iova(const VhostIOVATree *tree,
+                                        const DMAMap *map)
+{
+    return iova_tree_find_iova(tree->iova_taddr_map, map);
+}
+
+/**
+ * Allocate a new mapping
+ *
+ * @tree: The iova tree
+ * @map: The iova map
+ *
+ * Returns:
+ * - IOVA_OK if the map fits in the container
+ * - IOVA_ERR_INVALID if the map does not make sense (like size overflow)
+ * - IOVA_ERR_NOMEM if tree cannot allocate more space.
+ *
+ * It returns assignated iova in map->iova if return value is VHOST_DMA_MAP_OK.
+ */
+int vhost_iova_tree_map_alloc(VhostIOVATree *tree, DMAMap *map)
+{
+    /* Some vhost devices do not like addr 0. Skip first page */
+    hwaddr iova_first = tree->iova_first ?: qemu_real_host_page_size;
+
+    if (map->translated_addr + map->size < map->translated_addr ||
+        map->perm == IOMMU_NONE) {
+        return IOVA_ERR_INVALID;
+    }
+
+    /* Allocate a node in IOVA address */
+    return iova_tree_alloc_map(tree->iova_taddr_map, map, iova_first,
+                               tree->iova_last);
+}
+
+/**
+ * Remove existing mappings from iova tree
+ *
+ * @iova_tree: The vhost iova tree
+ * @map: The map to remove
+ */
+void vhost_iova_tree_remove(VhostIOVATree *iova_tree, const DMAMap *map)
+{
+    iova_tree_remove(iova_tree->iova_taddr_map, map);
+}
diff --git a/hw/virtio/vhost-iova-tree.h b/hw/virtio/vhost-iova-tree.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/hw/virtio/vhost-iova-tree.h
@@ -XXX,XX +XXX,XX @@
+/*
+ * vhost software live migration iova tree
+ *
+ * SPDX-FileCopyrightText: Red Hat, Inc. 2021
+ * SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef HW_VIRTIO_VHOST_IOVA_TREE_H
+#define HW_VIRTIO_VHOST_IOVA_TREE_H
+
+#include "qemu/iova-tree.h"
+#include "exec/memory.h"
+
+typedef struct VhostIOVATree VhostIOVATree;
+
+VhostIOVATree *vhost_iova_tree_new(uint64_t iova_first, uint64_t iova_last);
+void vhost_iova_tree_delete(VhostIOVATree *iova_tree);
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(VhostIOVATree, vhost_iova_tree_delete);
+
+const DMAMap *vhost_iova_tree_find_iova(const VhostIOVATree *iova_tree,
+                                        const DMAMap *map);
+int vhost_iova_tree_map_alloc(VhostIOVATree *iova_tree, DMAMap *map);
+void vhost_iova_tree_remove(VhostIOVATree *iova_tree, const DMAMap *map);
+
+#endif
-- 
2.7.4

From: Eugenio Pérez <eperezma@redhat.com>

Use translations added in VhostIOVATree in SVQ.

Only introduce usage here, not allocation and deallocation. As with
previous patches, we use the dead code paths of shadow_vqs_enabled to
avoid commiting too many changes at once. These are impossible to take
at the moment.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.c |  75 +++++++++++++++++++++--
 hw/virtio/vhost-shadow-virtqueue.h |   6 +-
 hw/virtio/vhost-vdpa.c             | 122 +++++++++++++++++++++++++++++++------
 include/hw/virtio/vhost-vdpa.h     |   3 +
 4 files changed, 181 insertions(+), 25 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -XXX,XX +XXX,XX @@ static uint16_t vhost_svq_available_slots(const VhostShadowVirtqueue *svq)
     return svq->vring.num - (svq->shadow_avail_idx - svq->shadow_used_idx);
 }
 
+/**
+ * Translate addresses between the qemu's virtual address and the SVQ IOVA
+ *
+ * @svq: Shadow VirtQueue
+ * @vaddr: Translated IOVA addresses
+ * @iovec: Source qemu's VA addresses
+ * @num: Length of iovec and minimum length of vaddr
+ */
+static bool vhost_svq_translate_addr(const VhostShadowVirtqueue *svq,
+                                     void **addrs, const struct iovec *iovec,
+                                     size_t num)
+{
+    if (num == 0) {
+        return true;
+    }
+
+    for (size_t i = 0; i < num; ++i) {
+        DMAMap needle = {
+            .translated_addr = (hwaddr)iovec[i].iov_base,
+            .size = iovec[i].iov_len,
+        };
+        size_t off;
+
+        const DMAMap *map = vhost_iova_tree_find_iova(svq->iova_tree, &needle);
+        /*
+         * Map cannot be NULL since iova map contains all guest space and
+         * qemu already has a physical address mapped
+         */
+        if (unlikely(!map)) {
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "Invalid address 0x%"HWADDR_PRIx" given by guest",
+                          needle.translated_addr);
+            return false;
+        }
+
+        off = needle.translated_addr - map->translated_addr;
+        addrs[i] = (void *)(map->iova + off);
+
+        if (unlikely(int128_gt(int128_add(needle.translated_addr,
+                                          iovec[i].iov_len),
+                               map->translated_addr + map->size))) {
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "Guest buffer expands over iova range");
+            return false;
+        }
+    }
+
+    return true;
+}
+
 static void vhost_vring_write_descs(VhostShadowVirtqueue *svq,
+                                    void * const *sg,
                                     const struct iovec *iovec,
                                     size_t num, bool more_descs, bool write)
 {
@@ -XXX,XX +XXX,XX @@ static void vhost_vring_write_descs(VhostShadowVirtqueue *svq,
         } else {
             descs[i].flags = flags;
         }
-        descs[i].addr = cpu_to_le64((hwaddr)iovec[n].iov_base);
+        descs[i].addr = cpu_to_le64((hwaddr)sg[n]);
         descs[i].len = cpu_to_le32(iovec[n].iov_len);
 
         last = i;
@@ -XXX,XX +XXX,XX @@ static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
 {
     unsigned avail_idx;
     vring_avail_t *avail = svq->vring.avail;
+    bool ok;
+    g_autofree void **sgs = g_new(void *, MAX(elem->out_num, elem->in_num));
 
     *head = svq->free_head;
 
@@ -XXX,XX +XXX,XX @@ static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
         return false;
     }
 
-    vhost_vring_write_descs(svq, elem->out_sg, elem->out_num,
+    ok = vhost_svq_translate_addr(svq, sgs, elem->out_sg, elem->out_num);
+    if (unlikely(!ok)) {
+        return false;
+    }
+    vhost_vring_write_descs(svq, sgs, elem->out_sg, elem->out_num,
                             elem->in_num > 0, false);
-    vhost_vring_write_descs(svq, elem->in_sg, elem->in_num, false, true);
+
+
+    ok = vhost_svq_translate_addr(svq, sgs, elem->in_sg, elem->in_num);
+    if (unlikely(!ok)) {
+        return false;
+    }
+
+    vhost_vring_write_descs(svq, sgs, elem->in_sg, elem->in_num, false, true);
 
     /*
      * Put the entry in the available array (but don't update avail->idx until
@@ -XXX,XX +XXX,XX @@ void vhost_svq_stop(VhostShadowVirtqueue *svq)
  * Creates vhost shadow virtqueue, and instructs the vhost device to use the
  * shadow methods and file descriptors.
  *
+ * @iova_tree: Tree to perform descriptors translations
+ *
  * Returns the new virtqueue or NULL.
  *
  * In case of error, reason is reported through error_report.
  */
-VhostShadowVirtqueue *vhost_svq_new(void)
+VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree)
 {
     g_autofree VhostShadowVirtqueue *svq = g_new0(VhostShadowVirtqueue, 1);
     int r;
@@ -XXX,XX +XXX,XX @@ VhostShadowVirtqueue *vhost_svq_new(void)
 
     event_notifier_init_fd(&svq->svq_kick, VHOST_FILE_UNBIND);
     event_notifier_set_handler(&svq->hdev_call, vhost_svq_handle_call);
+    svq->iova_tree = iova_tree;
     return g_steal_pointer(&svq);
 
 err_init_hdev_call:
diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -XXX,XX +XXX,XX @@
 #include "qemu/event_notifier.h"
 #include "hw/virtio/virtio.h"
 #include "standard-headers/linux/vhost_types.h"
+#include "hw/virtio/vhost-iova-tree.h"
 
 /* Shadow virtqueue to relay notifications */
 typedef struct VhostShadowVirtqueue {
@@ -XXX,XX +XXX,XX @@ typedef struct VhostShadowVirtqueue {
     /* Virtio device */
     VirtIODevice *vdev;
 
+    /* IOVA mapping */
+    VhostIOVATree *iova_tree;
+
     /* Map for use the guest's descriptors */
     VirtQueueElement **ring_id_maps;
 
@@ -XXX,XX +XXX,XX @@ void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
                      VirtQueue *vq);
 void vhost_svq_stop(VhostShadowVirtqueue *svq);
 
-VhostShadowVirtqueue *vhost_svq_new(void);
+VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree);
 
 void vhost_svq_free(gpointer vq);
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(VhostShadowVirtqueue, vhost_svq_free);
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -XXX,XX +XXX,XX @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener,
                                          vaddr, section->readonly);
 
     llsize = int128_sub(llend, int128_make64(iova));
+    if (v->shadow_vqs_enabled) {
+        DMAMap mem_region = {
+            .translated_addr = (hwaddr)vaddr,
+            .size = int128_get64(llsize) - 1,
+            .perm = IOMMU_ACCESS_FLAG(true, section->readonly),
+        };
+
+        int r = vhost_iova_tree_map_alloc(v->iova_tree, &mem_region);
+        if (unlikely(r != IOVA_OK)) {
+            error_report("Can't allocate a mapping (%d)", r);
+            goto fail;
+        }
+
+        iova = mem_region.iova;
+    }
 
     vhost_vdpa_iotlb_batch_begin_once(v);
     ret = vhost_vdpa_dma_map(v, iova, int128_get64(llsize),
@@ -XXX,XX +XXX,XX @@ static void vhost_vdpa_listener_region_del(MemoryListener *listener,
 
     llsize = int128_sub(llend, int128_make64(iova));
 
+    if (v->shadow_vqs_enabled) {
+        const DMAMap *result;
+        const void *vaddr = memory_region_get_ram_ptr(section->mr) +
+            section->offset_within_region +
+            (iova - section->offset_within_address_space);
+        DMAMap mem_region = {
+            .translated_addr = (hwaddr)vaddr,
+            .size = int128_get64(llsize) - 1,
+        };
+
+        result = vhost_iova_tree_find_iova(v->iova_tree, &mem_region);
+        iova = result->iova;
+        vhost_iova_tree_remove(v->iova_tree, &mem_region);
+    }
     vhost_vdpa_iotlb_batch_begin_once(v);
     ret = vhost_vdpa_dma_unmap(v, iova, int128_get64(llsize));
     if (ret) {
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
 
     shadow_vqs = g_ptr_array_new_full(hdev->nvqs, vhost_svq_free);
     for (unsigned n = 0; n < hdev->nvqs; ++n) {
-        g_autoptr(VhostShadowVirtqueue) svq = vhost_svq_new();
+        g_autoptr(VhostShadowVirtqueue) svq = vhost_svq_new(v->iova_tree);
 
         if (unlikely(!svq)) {
             error_setg(errp, "Cannot create svq %u", n);
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_svq_set_fds(struct vhost_dev *dev,
 /**
  * Unmap a SVQ area in the device
  */
-static bool vhost_vdpa_svq_unmap_ring(struct vhost_vdpa *v, hwaddr iova,
-                                      hwaddr size)
+static bool vhost_vdpa_svq_unmap_ring(struct vhost_vdpa *v,
+                                      const DMAMap *needle)
 {
+    const DMAMap *result = vhost_iova_tree_find_iova(v->iova_tree, needle);
+    hwaddr size;
     int r;
 
-    size = ROUND_UP(size, qemu_real_host_page_size);
-    r = vhost_vdpa_dma_unmap(v, iova, size);
+    if (unlikely(!result)) {
+        error_report("Unable to find SVQ address to unmap");
+        return false;
+    }
+
+    size = ROUND_UP(result->size, qemu_real_host_page_size);
+    r = vhost_vdpa_dma_unmap(v, result->iova, size);
     return r == 0;
 }
 
 static bool vhost_vdpa_svq_unmap_rings(struct vhost_dev *dev,
                                        const VhostShadowVirtqueue *svq)
 {
+    DMAMap needle = {};
     struct vhost_vdpa *v = dev->opaque;
     struct vhost_vring_addr svq_addr;
-    size_t device_size = vhost_svq_device_area_size(svq);
-    size_t driver_size = vhost_svq_driver_area_size(svq);
     bool ok;
 
     vhost_svq_get_vring_addr(svq, &svq_addr);
 
-    ok = vhost_vdpa_svq_unmap_ring(v, svq_addr.desc_user_addr, driver_size);
+    needle.translated_addr = svq_addr.desc_user_addr;
+    ok = vhost_vdpa_svq_unmap_ring(v, &needle);
     if (unlikely(!ok)) {
         return false;
     }
 
-    return vhost_vdpa_svq_unmap_ring(v, svq_addr.used_user_addr, device_size);
+    needle.translated_addr = svq_addr.used_user_addr;
+    return vhost_vdpa_svq_unmap_ring(v, &needle);
+}
+
+/**
+ * Map the SVQ area in the device
+ *
+ * @v: Vhost-vdpa device
+ * @needle: The area to search iova
+ * @errorp: Error pointer
+ */
+static bool vhost_vdpa_svq_map_ring(struct vhost_vdpa *v, DMAMap *needle,
+                                    Error **errp)
+{
+    int r;
+
+    r = vhost_iova_tree_map_alloc(v->iova_tree, needle);
+    if (unlikely(r != IOVA_OK)) {
+        error_setg(errp, "Cannot allocate iova (%d)", r);
+        return false;
+    }
+
+    r = vhost_vdpa_dma_map(v, needle->iova, needle->size + 1,
+                           (void *)needle->translated_addr,
+                           needle->perm == IOMMU_RO);
+    if (unlikely(r != 0)) {
+        error_setg_errno(errp, -r, "Cannot map region to device");
+        vhost_iova_tree_remove(v->iova_tree, needle);
+    }
+
+    return r == 0;
 }
 
 /**
@@ -XXX,XX +XXX,XX @@ static bool vhost_vdpa_svq_map_rings(struct vhost_dev *dev,
                                      struct vhost_vring_addr *addr,
                                      Error **errp)
 {
+    DMAMap device_region, driver_region;
+    struct vhost_vring_addr svq_addr;
     struct vhost_vdpa *v = dev->opaque;
     size_t device_size = vhost_svq_device_area_size(svq);
     size_t driver_size = vhost_svq_driver_area_size(svq);
-    int r;
+    size_t avail_offset;
+    bool ok;
 
     ERRP_GUARD();
-    vhost_svq_get_vring_addr(svq, addr);
+    vhost_svq_get_vring_addr(svq, &svq_addr);
 
-    r = vhost_vdpa_dma_map(v, addr->desc_user_addr, driver_size,
-                           (void *)addr->desc_user_addr, true);
-    if (unlikely(r != 0)) {
-        error_setg_errno(errp, -r, "Cannot create vq driver region: ");
+    driver_region = (DMAMap) {
+        .translated_addr = svq_addr.desc_user_addr,
+        .size = driver_size - 1,
+        .perm = IOMMU_RO,
+    };
+    ok = vhost_vdpa_svq_map_ring(v, &driver_region, errp);
+    if (unlikely(!ok)) {
+        error_prepend(errp, "Cannot create vq driver region: ");
         return false;
     }
+    addr->desc_user_addr = driver_region.iova;
+    avail_offset = svq_addr.avail_user_addr - svq_addr.desc_user_addr;
+    addr->avail_user_addr = driver_region.iova + avail_offset;
 
-    r = vhost_vdpa_dma_map(v, addr->used_user_addr, device_size,
-                           (void *)addr->used_user_addr, false);
-    if (unlikely(r != 0)) {
-        error_setg_errno(errp, -r, "Cannot create vq device region: ");
+    device_region = (DMAMap) {
+        .translated_addr = svq_addr.used_user_addr,
+        .size = device_size - 1,
+        .perm = IOMMU_RW,
+    };
+    ok = vhost_vdpa_svq_map_ring(v, &device_region, errp);
+    if (unlikely(!ok)) {
+        error_prepend(errp, "Cannot create vq device region: ");
+        vhost_vdpa_svq_unmap_ring(v, &driver_region);
     }
+    addr->used_user_addr = device_region.iova;
 
-    return r == 0;
+    return ok;
 }
 
 static bool vhost_vdpa_svq_setup(struct vhost_dev *dev,
diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -XXX,XX +XXX,XX @@
 
 #include <gmodule.h>
 
+#include "hw/virtio/vhost-iova-tree.h"
 #include "hw/virtio/virtio.h"
 #include "standard-headers/linux/vhost_types.h"
 
@@ -XXX,XX +XXX,XX @@ typedef struct vhost_vdpa {
     MemoryListener listener;
     struct vhost_vdpa_iova_range iova_range;
     bool shadow_vqs_enabled;
+    /* IOVA mapping used by the Shadow Virtqueue */
+    VhostIOVATree *iova_tree;
     GPtrArray *shadow_vqs;
     struct vhost_dev *dev;
     VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
-- 
2.7.4

From: Eugenio Pérez <eperezma@redhat.com>

This is needed to achieve migration, so the destination can restore its
index.

Setting base as last used idx, so destination will see as available all
the entries that the device did not use, including the in-flight
processing ones.

This is ok for networking, but other kinds of devices might have
problems with these retransmissions.

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_base(struct vhost_dev *dev,
 static int vhost_vdpa_get_vring_base(struct vhost_dev *dev,
                                        struct vhost_vring_state *ring)
 {
+    struct vhost_vdpa *v = dev->opaque;
     int ret;
 
+    if (v->shadow_vqs_enabled) {
+        VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs,
+                                                      ring->index);
+
+        /*
+         * Setting base as last used idx, so destination will see as available
+         * all the entries that the device did not use, including the in-flight
+         * processing ones.
+         *
+         * TODO: This is ok for networking, but other kinds of devices might
+         * have problems with these retransmissions.
+         */
+        ring->num = svq->last_used_idx;
+        return 0;
+    }
+
     ret = vhost_vdpa_call(dev, VHOST_GET_VRING_BASE, ring);
     trace_vhost_vdpa_get_vring_base(dev, ring->index, ring->num);
     return ret;
-- 
2.7.4

From: Eugenio Pérez <eperezma@redhat.com>

SVQ is able to log the dirty bits by itself, so let's use it to not
block migration.

Also, ignore set and clear of VHOST_F_LOG_ALL on set_features if SVQ is
enabled. Even if the device supports it, the reports would be nonsense
because SVQ memory is in the qemu region.

The log region is still allocated. Future changes might skip that, but
this series is already long enough.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/vhost-vdpa.c         | 39 +++++++++++++++++++++++++++++++++++----
 include/hw/virtio/vhost-vdpa.h |  1 +
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -XXX,XX +XXX,XX @@ static bool vhost_vdpa_one_time_request(struct vhost_dev *dev)
     return v->index != 0;
 }
 
+static int vhost_vdpa_get_dev_features(struct vhost_dev *dev,
+                                       uint64_t *features)
+{
+    int ret;
+
+    ret = vhost_vdpa_call(dev, VHOST_GET_FEATURES, features);
+    trace_vhost_vdpa_get_features(dev, *features);
+    return ret;
+}
+
 static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
                                Error **errp)
 {
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
         return 0;
     }
 
-    r = hdev->vhost_ops->vhost_get_features(hdev, &dev_features);
+    r = vhost_vdpa_get_dev_features(hdev, &dev_features);
     if (r != 0) {
         error_setg_errno(errp, -r, "Can't get vdpa device features");
         return r;
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_mem_table(struct vhost_dev *dev,
 static int vhost_vdpa_set_features(struct vhost_dev *dev,
                                    uint64_t features)
 {
+    struct vhost_vdpa *v = dev->opaque;
     int ret;
 
     if (vhost_vdpa_one_time_request(dev)) {
         return 0;
     }
 
+    if (v->shadow_vqs_enabled) {
+        if ((v->acked_features ^ features) == BIT_ULL(VHOST_F_LOG_ALL)) {
+            /*
+             * QEMU is just trying to enable or disable logging. SVQ handles
+             * this sepparately, so no need to forward this.
+             */
+            v->acked_features = features;
+            return 0;
+        }
+
+        v->acked_features = features;
+
+        /* We must not ack _F_LOG if SVQ is enabled */
+        features &= ~BIT_ULL(VHOST_F_LOG_ALL);
+    }
+
     trace_vhost_vdpa_set_features(dev, features);
     ret = vhost_vdpa_call(dev, VHOST_SET_FEATURES, &features);
     if (ret) {
@@ -XXX,XX +XXX,XX @@ static int vhost_vdpa_set_vring_call(struct vhost_dev *dev,
 static int vhost_vdpa_get_features(struct vhost_dev *dev,
                                      uint64_t *features)
 {
-    int ret;
+    struct vhost_vdpa *v = dev->opaque;
+    int ret = vhost_vdpa_get_dev_features(dev, features);
+
+    if (ret == 0 && v->shadow_vqs_enabled) {
+        /* Add SVQ logging capabilities */
+        *features |= BIT_ULL(VHOST_F_LOG_ALL);
+    }
 
-    ret = vhost_vdpa_call(dev, VHOST_GET_FEATURES, features);
-    trace_vhost_vdpa_get_features(dev, *features);
     return ret;
 }
 
diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index XXXXXXX..XXXXXXX 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -XXX,XX +XXX,XX @@ typedef struct vhost_vdpa {
     bool iotlb_batch_begin_sent;
     MemoryListener listener;
     struct vhost_vdpa_iova_range iova_range;
+    uint64_t acked_features;
     bool shadow_vqs_enabled;
     /* IOVA mapping used by the Shadow Virtqueue */
     VhostIOVATree *iova_tree;
-- 
2.7.4