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[PATCH v4 1/2] vhost: register and change IOMMU flag depending on Device-TLB state

Viktor Prutyanov posted 2 patches 2 years, 8 months ago
Maintainers: "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com>
There is a newer version of this series
[PATCH v4 1/2] vhost: register and change IOMMU flag depending on Device-TLB state
Posted by Viktor Prutyanov 2 years, 8 months ago 
The guest can disable or never enable Device-TLB. In these cases,
it can't be used even if enabled in QEMU. So, check Device-TLB state
before registering IOMMU notifier and select unmap flag depending on
that. Also, implement a way to change IOMMU notifier flag if Device-TLB
state is changed.

Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2001312
Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
---
 hw/virtio/vhost.c         | 38 ++++++++++++++++++++++++++------------
 include/hw/virtio/vhost.h |  1 +
 2 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 23da579ce2..e48507b5a1 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -781,7 +781,6 @@ static void vhost_iommu_region_add(MemoryListener *listener,
     Int128 end;
     int iommu_idx;
     IOMMUMemoryRegion *iommu_mr;
-    int ret;
 
     if (!memory_region_is_iommu(section->mr)) {
         return;
@@ -796,7 +795,9 @@ static void vhost_iommu_region_add(MemoryListener *listener,
     iommu_idx = memory_region_iommu_attrs_to_index(iommu_mr,
                                                    MEMTXATTRS_UNSPECIFIED);
     iommu_notifier_init(&iommu->n, vhost_iommu_unmap_notify,
-                        IOMMU_NOTIFIER_DEVIOTLB_UNMAP,
+                        dev->vdev->device_iotlb_enabled ?
+                            IOMMU_NOTIFIER_DEVIOTLB_UNMAP :
+                            IOMMU_NOTIFIER_UNMAP,
                         section->offset_within_region,
                         int128_get64(end),
                         iommu_idx);
@@ -804,16 +805,8 @@ static void vhost_iommu_region_add(MemoryListener *listener,
     iommu->iommu_offset = section->offset_within_address_space -
                           section->offset_within_region;
     iommu->hdev = dev;
-    ret = memory_region_register_iommu_notifier(section->mr, &iommu->n, NULL);
-    if (ret) {
-        /*
-         * Some vIOMMUs do not support dev-iotlb yet.  If so, try to use the
-         * UNMAP legacy message
-         */
-        iommu->n.notifier_flags = IOMMU_NOTIFIER_UNMAP;
-        memory_region_register_iommu_notifier(section->mr, &iommu->n,
-                                              &error_fatal);
-    }
+    memory_region_register_iommu_notifier(section->mr, &iommu->n,
+                                          &error_fatal);
     QLIST_INSERT_HEAD(&dev->iommu_list, iommu, iommu_next);
     /* TODO: can replay help performance here? */
 }
@@ -841,6 +834,27 @@ static void vhost_iommu_region_del(MemoryListener *listener,
     }
 }
 
+void vhost_toggle_device_iotlb(VirtIODevice *vdev)
+{
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
+    struct vhost_dev *dev;
+    struct vhost_iommu *iommu;
+
+    if (vdev->vhost_started) {
+        dev = vdc->get_vhost(vdev);
+    } else {
+        return;
+    }
+
+    QLIST_FOREACH(iommu, &dev->iommu_list, iommu_next) {
+        memory_region_unregister_iommu_notifier(iommu->mr, &iommu->n);
+        iommu->n.notifier_flags = vdev->device_iotlb_enabled ?
+                IOMMU_NOTIFIER_DEVIOTLB_UNMAP : IOMMU_NOTIFIER_UNMAP;
+        memory_region_register_iommu_notifier(iommu->mr, &iommu->n,
+                                              &error_fatal);
+    }
+}
+
 static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
                                     struct vhost_virtqueue *vq,
                                     unsigned idx, bool enable_log)
diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index f7f10c8fb7..6a173cb9fa 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -320,6 +320,7 @@ bool vhost_has_free_slot(void);
 int vhost_net_set_backend(struct vhost_dev *hdev,
                           struct vhost_vring_file *file);
 
+void vhost_toggle_device_iotlb(VirtIODevice *vdev);
 int vhost_device_iotlb_miss(struct vhost_dev *dev, uint64_t iova, int write);
 
 int vhost_virtqueue_start(struct vhost_dev *dev, struct VirtIODevice *vdev,
-- 
2.21.0
Re: [PATCH v4 1/2] vhost: register and change IOMMU flag depending on Device-TLB state
Posted by Jason Wang 2 years, 8 months ago 
On Thu, May 25, 2023 at 8:58 PM Viktor Prutyanov <viktor@daynix.com> wrote:
>
> The guest can disable or never enable Device-TLB. In these cases,
> it can't be used even if enabled in QEMU. So, check Device-TLB state
> before registering IOMMU notifier and select unmap flag depending on
> that. Also, implement a way to change IOMMU notifier flag if Device-TLB
> state is changed.
>
> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2001312
> Signed-off-by: Viktor Prutyanov <viktor@daynix.com>

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks

> ---
>  hw/virtio/vhost.c         | 38 ++++++++++++++++++++++++++------------
>  include/hw/virtio/vhost.h |  1 +
>  2 files changed, 27 insertions(+), 12 deletions(-)
>
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index 23da579ce2..e48507b5a1 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -781,7 +781,6 @@ static void vhost_iommu_region_add(MemoryListener *listener,
>      Int128 end;
>      int iommu_idx;
>      IOMMUMemoryRegion *iommu_mr;
> -    int ret;
>
>      if (!memory_region_is_iommu(section->mr)) {
>          return;
> @@ -796,7 +795,9 @@ static void vhost_iommu_region_add(MemoryListener *listener,
>      iommu_idx = memory_region_iommu_attrs_to_index(iommu_mr,
>                                                     MEMTXATTRS_UNSPECIFIED);
>      iommu_notifier_init(&iommu->n, vhost_iommu_unmap_notify,
> -                        IOMMU_NOTIFIER_DEVIOTLB_UNMAP,
> +                        dev->vdev->device_iotlb_enabled ?
> +                            IOMMU_NOTIFIER_DEVIOTLB_UNMAP :
> +                            IOMMU_NOTIFIER_UNMAP,
>                          section->offset_within_region,
>                          int128_get64(end),
>                          iommu_idx);
> @@ -804,16 +805,8 @@ static void vhost_iommu_region_add(MemoryListener *listener,
>      iommu->iommu_offset = section->offset_within_address_space -
>                            section->offset_within_region;
>      iommu->hdev = dev;
> -    ret = memory_region_register_iommu_notifier(section->mr, &iommu->n, NULL);
> -    if (ret) {
> -        /*
> -         * Some vIOMMUs do not support dev-iotlb yet.  If so, try to use the
> -         * UNMAP legacy message
> -         */
> -        iommu->n.notifier_flags = IOMMU_NOTIFIER_UNMAP;
> -        memory_region_register_iommu_notifier(section->mr, &iommu->n,
> -                                              &error_fatal);
> -    }
> +    memory_region_register_iommu_notifier(section->mr, &iommu->n,
> +                                          &error_fatal);
>      QLIST_INSERT_HEAD(&dev->iommu_list, iommu, iommu_next);
>      /* TODO: can replay help performance here? */
>  }
> @@ -841,6 +834,27 @@ static void vhost_iommu_region_del(MemoryListener *listener,
>      }
>  }
>
> +void vhost_toggle_device_iotlb(VirtIODevice *vdev)
> +{
> +    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
> +    struct vhost_dev *dev;
> +    struct vhost_iommu *iommu;
> +
> +    if (vdev->vhost_started) {
> +        dev = vdc->get_vhost(vdev);
> +    } else {
> +        return;
> +    }
> +
> +    QLIST_FOREACH(iommu, &dev->iommu_list, iommu_next) {
> +        memory_region_unregister_iommu_notifier(iommu->mr, &iommu->n);
> +        iommu->n.notifier_flags = vdev->device_iotlb_enabled ?
> +                IOMMU_NOTIFIER_DEVIOTLB_UNMAP : IOMMU_NOTIFIER_UNMAP;
> +        memory_region_register_iommu_notifier(iommu->mr, &iommu->n,
> +                                              &error_fatal);
> +    }
> +}
> +
>  static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
>                                      struct vhost_virtqueue *vq,
>                                      unsigned idx, bool enable_log)
> diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
> index f7f10c8fb7..6a173cb9fa 100644
> --- a/include/hw/virtio/vhost.h
> +++ b/include/hw/virtio/vhost.h
> @@ -320,6 +320,7 @@ bool vhost_has_free_slot(void);
>  int vhost_net_set_backend(struct vhost_dev *hdev,
>                            struct vhost_vring_file *file);
>
> +void vhost_toggle_device_iotlb(VirtIODevice *vdev);
>  int vhost_device_iotlb_miss(struct vhost_dev *dev, uint64_t iova, int write);
>
>  int vhost_virtqueue_start(struct vhost_dev *dev, struct VirtIODevice *vdev,
> --
> 2.21.0
>

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