Re: [PATCH] vdpa: do not save failed dma maps in SVQ iova tree

[Jason Wang]

在 2022/8/3 16:12, Eugenio Perez Martin 写道:
On Wed, Aug 3, 2022 at 10:09 AM Jason Wang <jasow...@redhat.com> wrote:
On Tue, Aug 2, 2022 at 10:39 PM Eugenio Pérez <epere...@redhat.com> wrote:
If a map fails for whatever reason, it must not be saved in the tree.
Otherwise, qemu will try to unmap it in cleanup, leaving to more errors.

Fixes: 34e3c94eda ("vdpa: Add custom IOTLB translations to SVQ")
Signed-off-by: Eugenio Pérez <epere...@redhat.com>
---
  hw/virtio/vhost-vdpa.c | 20 +++++++++++++-------
  1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 3ff9ce3501..e44c23dce5 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -176,6 +176,7 @@ static void vhost_vdpa_listener_commit(MemoryListener 
*listener)
  static void vhost_vdpa_listener_region_add(MemoryListener *listener,
                                             MemoryRegionSection *section)
  {
+    DMAMap mem_region = {};
      struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, 
listener);
      hwaddr iova;
      Int128 llend, llsize;
@@ -212,13 +213,13 @@ static void vhost_vdpa_listener_region_add(MemoryListener 
*listener,

      llsize = int128_sub(llend, int128_make64(iova));
      if (v->shadow_vqs_enabled) {
-        DMAMap mem_region = {
-            .translated_addr = (hwaddr)(uintptr_t)vaddr,
-            .size = int128_get64(llsize) - 1,
-            .perm = IOMMU_ACCESS_FLAG(true, section->readonly),
-        };
Nit: can we keep this part unchanged?

We can, but that implies we should look for iova again at fail_map
tag. If you are ok with that I'm fine to perform the search again.


I meant something like:

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 9a2daef7e3..edf40868e3 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -232,11 +232,15 @@ static void 
vhost_vdpa_listener_region_add(MemoryListener *listener,
                              vaddr, section->readonly);
     if (ret) {
         error_report("vhost vdpa map fail!");
-        goto fail;
+        goto fail_unmap;
     }

     return;

+fail_unmap:
+    if (v->shadow_vqs_enabled) {
+        vhost_iova_tree_remove(v->iova_tree, &mem_region);
+    }
 fail:
     /*
      * On the initfn path, store the first error in the container so we

Thanks



Thanks

+        int r;

-        int r = vhost_iova_tree_map_alloc(v->iova_tree, &mem_region);
+        mem_region.translated_addr = (hwaddr)(uintptr_t)vaddr,
+        mem_region.size = int128_get64(llsize) - 1,
+        mem_region.perm = IOMMU_ACCESS_FLAG(true, section->readonly),
+
+        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;
@@ -232,11 +233,16 @@ static void vhost_vdpa_listener_region_add(MemoryListener 
*listener,
                               vaddr, section->readonly);
      if (ret) {
          error_report("vhost vdpa map fail!");
-        goto fail;
+        goto fail_map;
      }

      return;

+fail_map:
+    if (v->shadow_vqs_enabled) {
+        vhost_iova_tree_remove(v->iova_tree, &mem_region);
+    }
+
  fail:
      /*
       * On the initfn path, store the first error in the container so we
--
2.31.1