[PATCH 1/1] virtio-pci: return RAM device MR when set host notifier success

[Gao Shiyuan via]

When vhost-user backend register memory region based host notifiers,
we should return RAM device MR of notify region MR's subregion in
virtio_address_space_lookup.

In seabios, it will use virtio PCI Configration Access Capability
access notify region when assign notify region above 4GB. This will
exit to QEMU and invoke virtio_address_space_write. When vhost-user
backend register memory region based host notifiers, return RAM device
MR instead of notify region MR is suitable.

Co-developed-by: Zuo Boqun <zuobo...@baidu.com>
Signed-off-by: Gao Shiyuan <gaoshiy...@baidu.com>
Signed-off-by: Zuo Boqun <zuobo...@baidu.com>
---
 hw/virtio/virtio-pci.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 9534730bba..167ac9718a 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -610,13 +610,22 @@ static MemoryRegion 
*virtio_address_space_lookup(VirtIOPCIProxy *proxy,
 {
     int i;
     VirtIOPCIRegion *reg;
+    MemoryRegion *mr, *submr;
 
     for (i = 0; i < ARRAY_SIZE(proxy->regs); ++i) {
         reg = &proxy->regs[i];
         if (*off >= reg->offset &&
             *off + len <= reg->offset + reg->size) {
             *off -= reg->offset;
-            return &reg->mr;
+            mr = &reg->mr;
+            QTAILQ_FOREACH(submr, &mr->subregions, subregions_link) {
+                if (*off >= submr->addr &&
+                    *off + len < submr->addr + submr->size) {
+                    *off -= submr->addr;
+                    return submr;
+                }
+            }
+            return mr;
         }
     }
 
-- 
2.39.3 (Apple Git-146)