vhost: generalize iommu memory region

We assumes the iommu_ops were attached to the root region of address
space. This may not be true for all kinds of IOMMU implementation and
especially after commit 3716d5902d74 ("pci: introduce a bus master
container"). So fix this by not assuming as->root has iommu_ops,
instead depending on the regions reported by memory listener through:

- register a memory listener to dma_as
- during region_add, if it's a region of IOMMU, register a specific
  IOMMU notifier, and store all notifiers in a list.
- during region_del, compare and delete the IOMMU notifier from the list

This is also a must for making vhost device IOTLB works for all types
of IOMMUs. Note, since we register one notifier during each
.region_add, the IOTLB may be flushed more than one times, this is
suboptimal and could be optimized in the future.

Reported-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Fixes: 3716d5902d74 ("pci: introduce a bus master container")
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: Maxime Coquelin <maxime.coquelin@redhat.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index 52f633ec89..a45032163d 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -37,10 +37,20 @@ struct vhost_log {
     vhost_log_chunk_t *log;
 };
 
+struct vhost_dev;
+struct vhost_iommu {
+    struct vhost_dev *hdev;
+    MemoryRegion *mr;
+    hwaddr iommu_offset;
+    IOMMUNotifier n;
+    QLIST_ENTRY(vhost_iommu) iommu_next;
+};
+
 struct vhost_memory;
 struct vhost_dev {
     VirtIODevice *vdev;
     MemoryListener memory_listener;
+    MemoryListener iommu_listener;
     struct vhost_memory *mem;
     int n_mem_sections;
     MemoryRegionSection *mem_sections;
@@ -64,6 +74,7 @@ struct vhost_dev {
     void *opaque;
     struct vhost_log *log;
     QLIST_ENTRY(vhost_dev) entry;
+    QLIST_HEAD(, vhost_iommu) iommu_list;
     IOMMUNotifier n;
 };