tyler.durden
/
audk
mirror of https://github.com/acidanthera/audk.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

OvmfPkg: VirtioLib: add Virtio10WriteFeatures() function 

In VirtIo 1.0, a device can reject a self-inconsistent feature bitmap
through the new VSTAT_FEATURES_OK status bit. (For example if the driver
requests a higher level feature but clears a prerequisite feature.) This
function is a small wrapper around
VIRTIO_DEVICE_PROTOCOL.SetGuestFeatures() that also verifies if the VirtIo
1.0 device accepts the feature bitmap.

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>
This commit is contained in:
Laszlo Ersek 2016-03-12 20:37:42 +01:00
parent acb81416cc
commit d0ece0d850
2 changed files with 121 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
OvmfPkg/Include/Library/VirtioLib.h
View File

@ -189,4 +189,50 @@ VirtioFlush (
OUT UINT32 *UsedLen OPTIONAL
);
/**
Report the feature bits to the VirtIo 1.0 device that the VirtIo 1.0 driver
understands.
In VirtIo 1.0, a device can reject a self-inconsistent feature bitmap through
the new VSTAT_FEATURES_OK status bit. (For example if the driver requests a
higher level feature but clears a prerequisite feature.) This function is a
small wrapper around VIRTIO_DEVICE_PROTOCOL.SetGuestFeatures() that also
verifies if the VirtIo 1.0 device accepts the feature bitmap.
@param[in] VirtIo Report feature bits to this device.
@param[in] Features The set of feature bits that the driver wishes
to report. The caller is responsible to perform
any masking before calling this function; the
value is directly written with
VIRTIO_DEVICE_PROTOCOL.SetGuestFeatures().
@param[in,out] DeviceStatus On input, the status byte most recently written
to the device's status register. On output (even
on error), DeviceStatus will be updated so that
it is suitable for further status bit
manipulation and writing to the device's status
register.
@retval EFI_SUCCESS The device accepted the configuration in Features.
@return EFI_UNSUPPORTED The device rejected the configuration in Features.
@retval EFI_UNSUPPORTED VirtIo->Revision is smaller than 1.0.0.
@return Error codes from the SetGuestFeatures(),
SetDeviceStatus(), GetDeviceStatus() member
functions.
**/
EFI_STATUS
EFIAPI
Virtio10WriteFeatures (
IN VIRTIO_DEVICE_PROTOCOL *VirtIo,
IN UINT64 Features,
IN OUT UINT8 *DeviceStatus
);
#endif // _VIRTIO_LIB_H_

75
OvmfPkg/Library/VirtioLib/VirtioLib.c
View File

@ -339,3 +339,78 @@ VirtioFlush (
return EFI_SUCCESS;
}
/**
Report the feature bits to the VirtIo 1.0 device that the VirtIo 1.0 driver
understands.
In VirtIo 1.0, a device can reject a self-inconsistent feature bitmap through
the new VSTAT_FEATURES_OK status bit. (For example if the driver requests a
higher level feature but clears a prerequisite feature.) This function is a
small wrapper around VIRTIO_DEVICE_PROTOCOL.SetGuestFeatures() that also
verifies if the VirtIo 1.0 device accepts the feature bitmap.
@param[in] VirtIo Report feature bits to this device.
@param[in] Features The set of feature bits that the driver wishes
to report. The caller is responsible to perform
any masking before calling this function; the
value is directly written with
VIRTIO_DEVICE_PROTOCOL.SetGuestFeatures().
@param[in,out] DeviceStatus On input, the status byte most recently written
to the device's status register. On output (even
on error), DeviceStatus will be updated so that
it is suitable for further status bit
manipulation and writing to the device's status
register.
@retval EFI_SUCCESS The device accepted the configuration in Features.
@return EFI_UNSUPPORTED The device rejected the configuration in Features.
@retval EFI_UNSUPPORTED VirtIo->Revision is smaller than 1.0.0.
@return Error codes from the SetGuestFeatures(),
SetDeviceStatus(), GetDeviceStatus() member
functions.
**/
EFI_STATUS
EFIAPI
Virtio10WriteFeatures (
IN VIRTIO_DEVICE_PROTOCOL *VirtIo,
IN UINT64 Features,
IN OUT UINT8 *DeviceStatus
)
{
EFI_STATUS Status;
if (VirtIo->Revision < VIRTIO_SPEC_REVISION (1, 0, 0)) {
return EFI_UNSUPPORTED;
}
Status = VirtIo->SetGuestFeatures (VirtIo, Features);
if (EFI_ERROR (Status)) {
return Status;
}
*DeviceStatus |= VSTAT_FEATURES_OK;
Status = VirtIo->SetDeviceStatus (VirtIo, *DeviceStatus);
if (EFI_ERROR (Status)) {
return Status;
}
Status = VirtIo->GetDeviceStatus (VirtIo, DeviceStatus);
if (EFI_ERROR (Status)) {
return Status;
}
if ((*DeviceStatus & VSTAT_FEATURES_OK) == 0) {
Status = EFI_UNSUPPORTED;
}
return Status;
}