OvmfPkg: VirtioRngDxe: adapt feature negotiation to virtio-1.0

[mirror_edk2.git] / OvmfPkg / VirtioRngDxe / VirtioRng.c

diff --git a/OvmfPkg/VirtioRngDxe/VirtioRng.c b/OvmfPkg/VirtioRngDxe/VirtioRng.c
index d916534aac63f3f27d7ea0ac5c59181971e75826..1a186d04082a3d5250c8a456333bbd3e9617fad6 100644 (file)
--- a/OvmfPkg/VirtioRngDxe/VirtioRng.c
+++ b/OvmfPkg/VirtioRngDxe/VirtioRng.c
@@ -242,6 +242,19 @@ VirtioRngInit (
     goto Failed;\r
   }\r
 \r
+  Features &= VIRTIO_F_VERSION_1;\r
+\r
+  //\r
+  // In virtio-1.0, feature negotiation is expected to complete before queue\r
+  // discovery, and the device can also reject the selected set of features.\r
+  //\r
+  if (Dev->VirtIo->Revision >= VIRTIO_SPEC_REVISION (1, 0, 0)) {\r
+    Status = Virtio10WriteFeatures (Dev->VirtIo, Features, &NextDevStat);\r
+    if (EFI_ERROR (Status)) {\r
+      goto Failed;\r
+    }\r
+  }\r
+\r
   //\r
   // step 4b -- allocate request virtqueue, just use #0\r
   //\r
@@ -290,14 +303,14 @@ VirtioRngInit (
   }\r
 \r
   //\r
-  // step 5 -- Report understood features and guest-tuneables. None are\r
-  // currently defined for VirtioRng, and no generic features are needed by\r
-  // this driver.\r
+  // step 5 -- Report understood features and guest-tuneables.\r
   //\r
-  Features &= 0;\r
-  Status = Dev->VirtIo->SetGuestFeatures (Dev->VirtIo, Features);\r
-  if (EFI_ERROR (Status)) {\r
-    goto ReleaseQueue;\r
+  if (Dev->VirtIo->Revision < VIRTIO_SPEC_REVISION (1, 0, 0)) {\r
+    Features &= ~(UINT64)VIRTIO_F_VERSION_1;\r
+    Status = Dev->VirtIo->SetGuestFeatures (Dev->VirtIo, Features);\r
+    if (EFI_ERROR (Status)) {\r
+      goto ReleaseQueue;\r
+    }\r
   }\r
 \r
   //\r