diff mbox

[edk2,wave,3,09/15] OvmfPkg: VirtioNetDxe: adapt feature negotiation to virtio-1.0

Message ID 1457960012-29481-10-git-send-email-lersek@redhat.com
State Superseded
Headers show

Commit Message

Laszlo Ersek March 14, 2016, 12:53 p.m. UTC 
Relative to virtio-0.9.5, virtio-1.0 reverses the order of queue discovery
and feature negotiation. In virtio-1.0, feature negotiation has to
complete first, and the device can also reject a self-inconsistent feature
request through the new VSTAT_FEATURES_OK status bit. (For example if the
driver requests a higher level feature but clears a prerequisite feature.)

Furthermore, we retain the VIRTIO_F_VERSION_1 feature bit if the
VIRTIO_DEVICE_PROTOCOL provider has high enough revision.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>

---
 OvmfPkg/VirtioNetDxe/SnpInitialize.c | 23 ++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

-- 
1.8.3.1


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diff mbox

Patch

diff --git a/OvmfPkg/VirtioNetDxe/SnpInitialize.c b/OvmfPkg/VirtioNetDxe/SnpInitialize.c
index f06b0a5a5742..38012a0df8d6 100644
--- a/OvmfPkg/VirtioNetDxe/SnpInitialize.c
+++ b/OvmfPkg/VirtioNetDxe/SnpInitialize.c
@@ -413,14 +413,27 @@  VirtioNetInitialize (
     goto DeviceFailed;
   }
 
   ASSERT (Features & VIRTIO_NET_F_MAC);
   ASSERT (Dev->Snm.MediaPresentSupported ==
     !!(Features & VIRTIO_NET_F_STATUS));
 
+  Features &= VIRTIO_NET_F_MAC | VIRTIO_NET_F_STATUS | VIRTIO_F_VERSION_1;
+
+  //
+  // In virtio-1.0, feature negotiation is expected to complete before queue
+  // discovery, and the device can also reject the selected set of features.
+  //
+  if (Dev->VirtIo->Revision >= VIRTIO_SPEC_REVISION (1, 0, 0)) {
+    Status = Virtio10WriteFeatures (Dev->VirtIo, Features, &NextDevStat);
+    if (EFI_ERROR (Status)) {
+      goto DeviceFailed;
+    }
+  }
+
   //
   // step 4b, 4c -- allocate and report virtqueues
   //
   Status = VirtioNetInitRing (Dev, VIRTIO_NET_Q_RX, &Dev->RxRing);
   if (EFI_ERROR (Status)) {
     goto DeviceFailed;
   }
@@ -429,18 +442,20 @@  VirtioNetInitialize (
   if (EFI_ERROR (Status)) {
     goto ReleaseRxRing;
   }
 
   //
   // step 5 -- keep only the features we want
   //
-  Features &= VIRTIO_NET_F_MAC | VIRTIO_NET_F_STATUS;
-  Status = Dev->VirtIo->SetGuestFeatures (Dev->VirtIo, Features);
-  if (EFI_ERROR (Status)) {
-    goto ReleaseTxRing;
+  if (Dev->VirtIo->Revision < VIRTIO_SPEC_REVISION (1, 0, 0)) {
+    Features &= ~(UINT64)VIRTIO_F_VERSION_1;
+    Status = Dev->VirtIo->SetGuestFeatures (Dev->VirtIo, Features);
+    if (EFI_ERROR (Status)) {
+      goto ReleaseTxRing;
+    }
   }
 
   //
   // step 6 -- virtio-net initialization complete
   //
   NextDevStat |= VSTAT_DRIVER_OK;
   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);