virtio-pci: Add lookup subregion of VirtIOPCIRegion MR

Now virtio_address_space_lookup only lookup common/isr/device/notify
MR and exclude their subregions.

When VHOST_USER_PROTOCOL_F_HOST_NOTIFIER enable, the notify MR has
host-notifier subregions and we need use host-notifier MR to
notify the hardware accelerator directly instead of eventfd notify.

Further more, maybe common/isr/device MR also has subregions in
the future, so need memory_region_find for each MR incluing
their subregions.

Add lookup subregion of VirtIOPCIRegion MR instead of only lookup container MR.

Fixes: a93c8d8 ("virtio-pci: Replace modern_as with direct access to modern_bar")
Co-developed-by: Zuo Boqun <zuoboqun@baidu.com>
Signed-off-by: Gao Shiyuan <gaoshiyuan@baidu.com>
Signed-off-by: Zuo Boqun <zuoboqun@baidu.com>
Message-Id: <20240903120304.97833-1-gaoshiyuan@baidu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 524b63e..4d832fe 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -615,8 +615,12 @@ static MemoryRegion *virtio_address_space_lookup(VirtIOPCIProxy *proxy,
         reg = &proxy->regs[i];
         if (*off >= reg->offset &&
             *off + len <= reg->offset + reg->size) {
-            *off -= reg->offset;
-            return &reg->mr;
+            MemoryRegionSection mrs = memory_region_find(&reg->mr,
+                                        *off - reg->offset, len);
+            assert(mrs.mr);
+            *off = mrs.offset_within_region;
+            memory_region_unref(mrs.mr);
+            return mrs.mr;
         }
     }