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[PATCH V2 2/2] vhost-vdpa: map virtqueue notification area if possible

Jason Wang posted 2 patches 4 years, 8 months ago
Maintainers: "Michael S. Tsirkin" <mst@redhat.com>
[PATCH V2 2/2] vhost-vdpa: map virtqueue notification area if possible
Posted by Jason Wang 4 years, 8 months ago 
This patch implements the vq notification mapping support for
vhost-vDPA. This is simply done by using mmap()/munmap() for the
vhost-vDPA fd during device start/stop. For the device without
notification mapping support, we fall back to eventfd based
notification gracefully.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
Changes since v1:
- use dev->vq_index to calculate the virtqueue index
- remove the unused host_notifier_set
---
 hw/virtio/vhost-vdpa.c         | 85 ++++++++++++++++++++++++++++++++++
 include/hw/virtio/vhost-vdpa.h |  6 +++
 2 files changed, 91 insertions(+)

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index dd4321bac2..f9a86afe64 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -285,12 +285,95 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque)
     return 0;
 }
 
+static void vhost_vdpa_host_notifier_uninit(struct vhost_dev *dev,
+                                            int queue_index)
+{
+    size_t page_size = qemu_real_host_page_size;
+    struct vhost_vdpa *v = dev->opaque;
+    VirtIODevice *vdev = dev->vdev;
+    VhostVDPAHostNotifier *n;
+
+    n = &v->notifier[queue_index];
+
+    if (n->addr) {
+        virtio_queue_set_host_notifier_mr(vdev, queue_index, &n->mr, false);
+        object_unparent(OBJECT(&n->mr));
+        munmap(n->addr, page_size);
+        n->addr = NULL;
+    }
+}
+
+static void vhost_vdpa_host_notifiers_uninit(struct vhost_dev *dev, int n)
+{
+    int i;
+
+    for (i = 0; i < n; i++) {
+        vhost_vdpa_host_notifier_uninit(dev, i);
+    }
+}
+
+static int vhost_vdpa_host_notifier_init(struct vhost_dev *dev, int queue_index)
+{
+    size_t page_size = qemu_real_host_page_size;
+    struct vhost_vdpa *v = dev->opaque;
+    VirtIODevice *vdev = dev->vdev;
+    VhostVDPAHostNotifier *n;
+    int fd = v->device_fd;
+    void *addr;
+    char *name;
+
+    vhost_vdpa_host_notifier_uninit(dev, queue_index);
+
+    n = &v->notifier[queue_index];
+
+    addr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, fd,
+                queue_index * page_size);
+    if (addr == MAP_FAILED) {
+        goto err;
+    }
+
+    name = g_strdup_printf("vhost-vdpa/host-notifier@%p mmaps[%d]",
+                           v, queue_index);
+    memory_region_init_ram_device_ptr(&n->mr, OBJECT(vdev), name,
+                                      page_size, addr);
+    g_free(name);
+
+    if (virtio_queue_set_host_notifier_mr(vdev, queue_index, &n->mr, true)) {
+        munmap(addr, page_size);
+        goto err;
+    }
+    n->addr = addr;
+
+    return 0;
+
+err:
+    return -1;
+}
+
+static void vhost_vdpa_host_notifiers_init(struct vhost_dev *dev)
+{
+    int i;
+
+    for (i = dev->vq_index; i < dev->vq_index + dev->nvqs; i++) {
+        if (vhost_vdpa_host_notifier_init(dev, i)) {
+            goto err;
+        }
+    }
+
+    return;
+
+err:
+    vhost_vdpa_host_notifiers_uninit(dev, i);
+    return;
+}
+
 static int vhost_vdpa_cleanup(struct vhost_dev *dev)
 {
     struct vhost_vdpa *v;
     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_VDPA);
     v = dev->opaque;
     trace_vhost_vdpa_cleanup(dev, v);
+    vhost_vdpa_host_notifiers_uninit(dev, dev->nvqs);
     memory_listener_unregister(&v->listener);
 
     dev->opaque = NULL;
@@ -467,6 +550,7 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
     if (started) {
         uint8_t status = 0;
         memory_listener_register(&v->listener, &address_space_memory);
+        vhost_vdpa_host_notifiers_init(dev);
         vhost_vdpa_set_vring_ready(dev);
         vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
         vhost_vdpa_call(dev, VHOST_VDPA_GET_STATUS, &status);
@@ -476,6 +560,7 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
         vhost_vdpa_reset_device(dev);
         vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE |
                                    VIRTIO_CONFIG_S_DRIVER);
+        vhost_vdpa_host_notifiers_uninit(dev, dev->nvqs);
         memory_listener_unregister(&v->listener);
 
         return 0;
diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index 9b81a409da..56bef30ec2 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -14,11 +14,17 @@
 
 #include "hw/virtio/virtio.h"
 
+typedef struct VhostVDPAHostNotifier {
+    MemoryRegion mr;
+    void *addr;
+} VhostVDPAHostNotifier;
+
 typedef struct vhost_vdpa {
     int device_fd;
     uint32_t msg_type;
     MemoryListener listener;
     struct vhost_dev *dev;
+    VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
 } VhostVDPA;
 
 extern AddressSpace address_space_memory;
-- 
2.25.1
Re: [PATCH V2 2/2] vhost-vdpa: map virtqueue notification area if possible
Posted by Si-Wei Liu 4 years, 8 months ago 
Looks good.

On 6/2/2021 1:41 AM, Jason Wang wrote:
> This patch implements the vq notification mapping support for
> vhost-vDPA. This is simply done by using mmap()/munmap() for the
> vhost-vDPA fd during device start/stop. For the device without
> notification mapping support, we fall back to eventfd based
> notification gracefully.
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>

> ---
> Changes since v1:
> - use dev->vq_index to calculate the virtqueue index
> - remove the unused host_notifier_set
> ---
>   hw/virtio/vhost-vdpa.c         | 85 ++++++++++++++++++++++++++++++++++
>   include/hw/virtio/vhost-vdpa.h |  6 +++
>   2 files changed, 91 insertions(+)
>
> diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> index dd4321bac2..f9a86afe64 100644
> --- a/hw/virtio/vhost-vdpa.c
> +++ b/hw/virtio/vhost-vdpa.c
> @@ -285,12 +285,95 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque)
>       return 0;
>   }
>   
> +static void vhost_vdpa_host_notifier_uninit(struct vhost_dev *dev,
> +                                            int queue_index)
> +{
> +    size_t page_size = qemu_real_host_page_size;
> +    struct vhost_vdpa *v = dev->opaque;
> +    VirtIODevice *vdev = dev->vdev;
> +    VhostVDPAHostNotifier *n;
> +
> +    n = &v->notifier[queue_index];
> +
> +    if (n->addr) {
> +        virtio_queue_set_host_notifier_mr(vdev, queue_index, &n->mr, false);
> +        object_unparent(OBJECT(&n->mr));
> +        munmap(n->addr, page_size);
> +        n->addr = NULL;
> +    }
> +}
> +
> +static void vhost_vdpa_host_notifiers_uninit(struct vhost_dev *dev, int n)
> +{
> +    int i;
> +
> +    for (i = 0; i < n; i++) {
> +        vhost_vdpa_host_notifier_uninit(dev, i);
> +    }
> +}
> +
> +static int vhost_vdpa_host_notifier_init(struct vhost_dev *dev, int queue_index)
> +{
> +    size_t page_size = qemu_real_host_page_size;
> +    struct vhost_vdpa *v = dev->opaque;
> +    VirtIODevice *vdev = dev->vdev;
> +    VhostVDPAHostNotifier *n;
> +    int fd = v->device_fd;
> +    void *addr;
> +    char *name;
> +
> +    vhost_vdpa_host_notifier_uninit(dev, queue_index);
> +
> +    n = &v->notifier[queue_index];
> +
> +    addr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, fd,
> +                queue_index * page_size);
> +    if (addr == MAP_FAILED) {
> +        goto err;
> +    }
> +
> +    name = g_strdup_printf("vhost-vdpa/host-notifier@%p mmaps[%d]",
> +                           v, queue_index);
> +    memory_region_init_ram_device_ptr(&n->mr, OBJECT(vdev), name,
> +                                      page_size, addr);
> +    g_free(name);
> +
> +    if (virtio_queue_set_host_notifier_mr(vdev, queue_index, &n->mr, true)) {
> +        munmap(addr, page_size);
> +        goto err;
> +    }
> +    n->addr = addr;
> +
> +    return 0;
> +
> +err:
> +    return -1;
> +}
> +
> +static void vhost_vdpa_host_notifiers_init(struct vhost_dev *dev)
> +{
> +    int i;
> +
> +    for (i = dev->vq_index; i < dev->vq_index + dev->nvqs; i++) {
> +        if (vhost_vdpa_host_notifier_init(dev, i)) {
> +            goto err;
> +        }
> +    }
> +
> +    return;
> +
> +err:
> +    vhost_vdpa_host_notifiers_uninit(dev, i);
> +    return;
> +}
> +
>   static int vhost_vdpa_cleanup(struct vhost_dev *dev)
>   {
>       struct vhost_vdpa *v;
>       assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_VDPA);
>       v = dev->opaque;
>       trace_vhost_vdpa_cleanup(dev, v);
> +    vhost_vdpa_host_notifiers_uninit(dev, dev->nvqs);
>       memory_listener_unregister(&v->listener);
>   
>       dev->opaque = NULL;
> @@ -467,6 +550,7 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
>       if (started) {
>           uint8_t status = 0;
>           memory_listener_register(&v->listener, &address_space_memory);
> +        vhost_vdpa_host_notifiers_init(dev);
>           vhost_vdpa_set_vring_ready(dev);
>           vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
>           vhost_vdpa_call(dev, VHOST_VDPA_GET_STATUS, &status);
> @@ -476,6 +560,7 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
>           vhost_vdpa_reset_device(dev);
>           vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE |
>                                      VIRTIO_CONFIG_S_DRIVER);
> +        vhost_vdpa_host_notifiers_uninit(dev, dev->nvqs);
>           memory_listener_unregister(&v->listener);
>   
>           return 0;
> diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
> index 9b81a409da..56bef30ec2 100644
> --- a/include/hw/virtio/vhost-vdpa.h
> +++ b/include/hw/virtio/vhost-vdpa.h
> @@ -14,11 +14,17 @@
>   
>   #include "hw/virtio/virtio.h"
>   
> +typedef struct VhostVDPAHostNotifier {
> +    MemoryRegion mr;
> +    void *addr;
> +} VhostVDPAHostNotifier;
> +
>   typedef struct vhost_vdpa {
>       int device_fd;
>       uint32_t msg_type;
>       MemoryListener listener;
>       struct vhost_dev *dev;
> +    VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
>   } VhostVDPA;
>   
>   extern AddressSpace address_space_memory;

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