OvmfPkg: VIRTIO_DEVICE_PROTOCOL: widen the Features bitmap to 64 bits

The virtio-1.0 spec widens the Features bitmap to 64 bits. Modify the
declarations of the GetDeviceFeatures() and SetGuestFeatures() protocol
member functions accordingly.

Normally, a protocol cannot be changed in incompatible ways if the GUID
stays the same; however, we've always been extremely clear that
VIRTIO_DEVICE_PROTOCOL is internal to edk2. See for example the top of
"OvmfPkg/Include/Protocol/VirtioDevice.h".

In this patch, all producers and consumers of the GetDeviceFeatures() and
SetGuestFeatures() protocol members are updated.

The drivers that currently produce these members are "legacy" drivers (in
virtio-1.0 terminology), and they cannot (and will not) handle feature
bits above BIT31. Therefore their conversion is only for compatibility
with the modified protocol interface. The consumers will be responsible
for checking the VIRTIO_DEVICE_PROTOCOL.Revision field, and for not
passing feature bits that these backends cannot handle.

The VirtioMmioGetDeviceFeatures() implementation stores the result of an
MmioRead32() call with normal assignment, so it needs no change beyond
adapting its prototype.

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>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

2 files changed, 15 insertions, 6 deletions

diff --git a/OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.h b/OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.h
index 6311ae849d..812061dc0c 100644
--- a/OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.h
+++ b/OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.h
@@ -83,7 +83,7 @@ EFI_STATUS
 EFIAPI

 VirtioPciGetDeviceFeatures (

   IN VIRTIO_DEVICE_PROTOCOL *This,

-  OUT UINT32                *DeviceFeatures

+  OUT UINT64                *DeviceFeatures

   );

 

 EFI_STATUS

@@ -125,7 +125,7 @@ EFI_STATUS
 EFIAPI

 VirtioPciSetGuestFeatures (

   IN VIRTIO_DEVICE_PROTOCOL  *This,

-  IN UINT32                   Features

+  IN UINT64                   Features

   );

 

 EFI_STATUS

diff --git a/OvmfPkg/VirtioPciDeviceDxe/VirtioPciFunctions.c b/OvmfPkg/VirtioPciDeviceDxe/VirtioPciFunctions.c
index 9c40fd94a6..d8d30f9af6 100644
--- a/OvmfPkg/VirtioPciDeviceDxe/VirtioPciFunctions.c
+++ b/OvmfPkg/VirtioPciDeviceDxe/VirtioPciFunctions.c
@@ -101,10 +101,12 @@ EFI_STATUS
 EFIAPI

 VirtioPciGetDeviceFeatures (

   IN VIRTIO_DEVICE_PROTOCOL *This,

-  OUT UINT32                *DeviceFeatures

+  OUT UINT64                *DeviceFeatures

   )

 {

   VIRTIO_PCI_DEVICE         *Dev;

+  EFI_STATUS                Status;

+  UINT32                    Features32;

 

   if (DeviceFeatures == NULL) {

     return EFI_INVALID_PARAMETER;

@@ -112,8 +114,12 @@ VirtioPciGetDeviceFeatures (
 

   Dev = VIRTIO_PCI_DEVICE_FROM_VIRTIO_DEVICE (This);

 

-  return VirtioPciIoRead (Dev, VIRTIO_PCI_OFFSET_DEVICE_FEATURES, sizeof (UINT32),

-      sizeof (UINT32), DeviceFeatures);

+  Status = VirtioPciIoRead (Dev, VIRTIO_PCI_OFFSET_DEVICE_FEATURES,

+             sizeof (UINT32), sizeof (UINT32), &Features32);

+  if (!EFI_ERROR (Status)) {

+    *DeviceFeatures = Features32;

+  }

+  return Status;

 }

 

 EFI_STATUS

@@ -177,13 +183,16 @@ EFI_STATUS
 EFIAPI

 VirtioPciSetGuestFeatures (

   IN VIRTIO_DEVICE_PROTOCOL  *This,

-  IN UINT32                   Features

+  IN UINT64                   Features

   )

 {

   VIRTIO_PCI_DEVICE *Dev;

 

   Dev = VIRTIO_PCI_DEVICE_FROM_VIRTIO_DEVICE (This);

 

+  if (Features > MAX_UINT32) {

+    return EFI_UNSUPPORTED;

+  }

   return VirtioPciIoWrite (Dev, VIRTIO_PCI_OFFSET_GUEST_FEATURES,

       sizeof (UINT32), Features);

 }