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 <[email protected]> Cc: Jordan Justen <[email protected]> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Laszlo Ersek <[email protected]> --- OvmfPkg/Include/Library/VirtioLib.h | 47 ++++++++++++ OvmfPkg/Library/VirtioLib/VirtioLib.c | 75 ++++++++++++++++++++ 2 files changed, 122 insertions(+) diff --git a/OvmfPkg/Include/Library/VirtioLib.h b/OvmfPkg/Include/Library/VirtioLib.h index decd4418af3d..989283c67d70 100644 --- a/OvmfPkg/Include/Library/VirtioLib.h +++ b/OvmfPkg/Include/Library/VirtioLib.h @@ -16,14 +16,15 @@ #ifndef _VIRTIO_LIB_H_ #define _VIRTIO_LIB_H_ #include <Protocol/VirtioDevice.h> #include <IndustryStandard/Virtio.h> +#include <IndustryStandard/Virtio10.h> /** Configure a virtio ring. This function sets up internal storage (the guest-host communication area) @@ -185,8 +186,54 @@ VirtioFlush ( IN VIRTIO_DEVICE_PROTOCOL *VirtIo, IN UINT16 VirtQueueId, IN OUT VRING *Ring, IN DESC_INDICES *Indices, 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_ diff --git a/OvmfPkg/Library/VirtioLib/VirtioLib.c b/OvmfPkg/Library/VirtioLib/VirtioLib.c index 4b1d78b5a03e..845f206369a3 100644 --- a/OvmfPkg/Library/VirtioLib/VirtioLib.c +++ b/OvmfPkg/Library/VirtioLib/VirtioLib.c @@ -335,7 +335,82 @@ VirtioFlush ( UsedElem = &Ring->Used.UsedElem[LastUsedIdx % Ring->QueueSize]; ASSERT (UsedElem->Id == Indices->HeadDescIdx); *UsedLen = UsedElem->Len; } 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; +} -- 1.8.3.1 _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
