The vhost-pci driver uses the remote guest physical address to send/receive
packets from the remote guest, so when sending the ving info to the vhost-pci
device, send the guest physical adress directly.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
---
 hw/virtio/vhost.c | 56 +++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 36 insertions(+), 20 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index dda7b8f..ffbda6c 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1057,26 +1057,38 @@ static int vhost_virtqueue_start(struct vhost_dev *dev,
         }
     }
 
-    vq->desc_size = s = l = virtio_queue_get_desc_size(vdev, idx);
     vq->desc_phys = a = virtio_queue_get_desc_addr(vdev, idx);
-    vq->desc = vhost_memory_map(dev, a, &l, 0);
-    if (!vq->desc || l != s) {
-        r = -ENOMEM;
-        goto fail_alloc_desc;
+    if (vhost_pci_enabled(dev)) {
+        vq->desc = (void *)a;
+    } else {
+        vq->desc_size = s = l = virtio_queue_get_desc_size(vdev, idx);
+        vq->desc = vhost_memory_map(dev, a, &l, 0);
+        if (!vq->desc || l != s) {
+            r = -ENOMEM;
+            goto fail_alloc_desc;
+        }
     }
     vq->avail_size = s = l = virtio_queue_get_avail_size(vdev, idx);
     vq->avail_phys = a = virtio_queue_get_avail_addr(vdev, idx);
-    vq->avail = vhost_memory_map(dev, a, &l, 0);
-    if (!vq->avail || l != s) {
-        r = -ENOMEM;
-        goto fail_alloc_avail;
+    if (vhost_pci_enabled(dev)) {
+        vq->avail = (void *)a;
+    } else {
+        vq->avail = vhost_memory_map(dev, a, &l, 0);
+        if (!vq->avail || l != s) {
+            r = -ENOMEM;
+            goto fail_alloc_avail;
+        }
     }
     vq->used_size = s = l = virtio_queue_get_used_size(vdev, idx);
     vq->used_phys = a = virtio_queue_get_used_addr(vdev, idx);
-    vq->used = vhost_memory_map(dev, a, &l, 1);
-    if (!vq->used || l != s) {
-        r = -ENOMEM;
-        goto fail_alloc_used;
+    if (vhost_pci_enabled(dev)) {
+        vq->used = (void *)a;
+    } else {
+        vq->used = vhost_memory_map(dev, a, &l, 1);
+        if (!vq->used || l != s) {
+            r = -ENOMEM;
+            goto fail_alloc_used;
+        }
     }
 
     r = vhost_virtqueue_set_addr(dev, vq, vhost_vq_index, dev->log_enabled);
@@ -1163,13 +1175,17 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev,
                                                 !virtio_is_big_endian(vdev),
                                                 vhost_vq_index);
     }
-
-    vhost_memory_unmap(dev, vq->used, virtio_queue_get_used_size(vdev, idx),
-                       1, virtio_queue_get_used_size(vdev, idx));
-    vhost_memory_unmap(dev, vq->avail, virtio_queue_get_avail_size(vdev, idx),
-                       0, virtio_queue_get_avail_size(vdev, idx));
-    vhost_memory_unmap(dev, vq->desc, virtio_queue_get_desc_size(vdev, idx),
-                       0, virtio_queue_get_desc_size(vdev, idx));
+    if (!vhost_pci_enabled(dev)) {
+        vhost_memory_unmap(dev, vq->used,
+                           virtio_queue_get_used_size(vdev, idx),
+                           1, virtio_queue_get_used_size(vdev, idx));
+        vhost_memory_unmap(dev, vq->avail,
+                           virtio_queue_get_avail_size(vdev, idx),
+                           0, virtio_queue_get_avail_size(vdev, idx));
+        vhost_memory_unmap(dev, vq->desc,
+                           virtio_queue_get_desc_size(vdev, idx),
+                           0, virtio_queue_get_desc_size(vdev, idx));
+    }
 }
 
 static void vhost_eventfd_add(MemoryListener *listener,
-- 
2.7.4

On Tue, Dec 05, 2017 at 11:33:16AM +0800, Wei Wang wrote:
> The vhost-pci driver uses the remote guest physical address to send/receive
> packets from the remote guest, so when sending the ving info to the vhost-pci
> device, send the guest physical adress directly.
> 
> Signed-off-by: Wei Wang <wei.w.wang@intel.com>
> ---
>  hw/virtio/vhost.c | 56 +++++++++++++++++++++++++++++++++++--------------------
>  1 file changed, 36 insertions(+), 20 deletions(-)

Can you do it inside vhost_memory_map()/vhost_memory_unmap() instead of
modifying callers?

Looks like vhost_dev_has_iommu() already takes this approach:

  static void *vhost_memory_map(struct vhost_dev *dev, hwaddr addr,
                                hwaddr *plen, int is_write)
  {
      if (!vhost_dev_has_iommu(dev)) {
          return cpu_physical_memory_map(addr, plen, is_write);
      } else {
          return (void *)(uintptr_t)addr;
      }
  }

  static void vhost_memory_unmap(struct vhost_dev *dev, void *buffer,
                                 hwaddr len, int is_write,
                                 hwaddr access_len)
  {
      if (!vhost_dev_has_iommu(dev)) {
          cpu_physical_memory_unmap(buffer, len, is_write, access_len);
      }
  }

On 12/06/2017 12:05 AM, Stefan Hajnoczi wrote:
> On Tue, Dec 05, 2017 at 11:33:16AM +0800, Wei Wang wrote:
>> The vhost-pci driver uses the remote guest physical address to send/receive
>> packets from the remote guest, so when sending the ving info to the vhost-pci
>> device, send the guest physical adress directly.
>>
>> Signed-off-by: Wei Wang <wei.w.wang@intel.com>
>> ---
>>   hw/virtio/vhost.c | 56 +++++++++++++++++++++++++++++++++++--------------------
>>   1 file changed, 36 insertions(+), 20 deletions(-)
> Can you do it inside vhost_memory_map()/vhost_memory_unmap() instead of
> modifying callers?
>
> Looks like vhost_dev_has_iommu() already takes this approach:
>
>    static void *vhost_memory_map(struct vhost_dev *dev, hwaddr addr,
>                                  hwaddr *plen, int is_write)
>    {
>        if (!vhost_dev_has_iommu(dev)) {
>            return cpu_physical_memory_map(addr, plen, is_write);
>        } else {
>            return (void *)(uintptr_t)addr;
>        }
>    }
>
>    static void vhost_memory_unmap(struct vhost_dev *dev, void *buffer,
>                                   hwaddr len, int is_write,
>                                   hwaddr access_len)
>    {
>        if (!vhost_dev_has_iommu(dev)) {
>            cpu_physical_memory_unmap(buffer, len, is_write, access_len);
>        }
>    }

Thanks for the reminder. I think this patch may be not needed with 
adding the F_IOMMU_PLATFORM feature.


Best,
Wei