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 <jasowang@redhat.com> wrote:
> > On Tue, Aug 2, 2022 at 10:39 PM Eugenio Pérez <eperezma@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 <eperezma@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