From 33c6b934bf973bd3e0f72805ad723558cfffaa7f Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Sat, 12 Mar 2016 14:41:26 +0100 Subject: OvmfPkg: VirtioNetDxe: adapt feature negotiation to virtio-1.0 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 Cc: Jordan Justen Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Laszlo Ersek Tested-by: Ard Biesheuvel Reviewed-by: Jordan Justen --- OvmfPkg/VirtioNetDxe/SnpInitialize.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) (limited to 'OvmfPkg/VirtioNetDxe') diff --git a/OvmfPkg/VirtioNetDxe/SnpInitialize.c b/OvmfPkg/VirtioNetDxe/SnpInitialize.c index f06b0a5a57..38012a0df8 100644 --- a/OvmfPkg/VirtioNetDxe/SnpInitialize.c +++ b/OvmfPkg/VirtioNetDxe/SnpInitialize.c @@ -417,6 +417,19 @@ VirtioNetInitialize ( 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 // @@ -433,10 +446,12 @@ VirtioNetInitialize ( // // 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; + } } // -- cgit v1.2.3