VmgExitLib.h File Reference

Functions
UINT64 EFIAPI	VmgExit (IN OUT GHCB *Ghcb, IN UINT64 ExitCode, IN UINT64 ExitInfo1, IN UINT64 ExitInfo2)
VOID EFIAPI	VmgInit (IN OUT GHCB *Ghcb, IN OUT BOOLEAN *InterruptState)
VOID EFIAPI	VmgDone (IN OUT GHCB *Ghcb, IN BOOLEAN InterruptState)
VOID EFIAPI	VmgSetOffsetValid (IN OUT GHCB *Ghcb, IN GHCB_REGISTER Offset)
BOOLEAN EFIAPI	VmgIsOffsetValid (IN GHCB *Ghcb, IN GHCB_REGISTER Offset)
EFI_STATUS EFIAPI	VmgExitHandleVc (IN OUT EFI_EXCEPTION_TYPE *ExceptionType, IN OUT EFI_SYSTEM_CONTEXT SystemContext)

Detailed Description

Public header file for the VMGEXIT Support library class.

This library class defines some routines used when invoking the VMGEXIT instruction in support of SEV-ES and to handle #VC exceptions.

Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent

Function Documentation

VOID EFIAPI VmgDone	(	IN OUT GHCB *	Ghcb,
		IN BOOLEAN	InterruptState
	)

Perform post-VMGEXIT cleanup.

Performs the necessary steps to cleanup after invoking VMGEXIT. Must be called after obtaining needed fields within the GHCB.

Parameters

[in,out]	Ghcb	A pointer to the GHCB
[in]	InterruptState	An indicator to conditionally (re)enable interrupts

UINT64 EFIAPI VmgExit	(	IN OUT GHCB *	Ghcb,
		IN UINT64	ExitCode,
		IN UINT64	ExitInfo1,
		IN UINT64	ExitInfo2
	)

Perform VMGEXIT.

Sets the necessary fields of the GHCB, invokes the VMGEXIT instruction and then handles the return actions.

Parameters

[in,out]	Ghcb	A pointer to the GHCB
[in]	ExitCode	VMGEXIT code to be assigned to the SwExitCode field of the GHCB.
[in]	ExitInfo1	VMGEXIT information to be assigned to the SwExitInfo1 field of the GHCB.
[in]	ExitInfo2	VMGEXIT information to be assigned to the SwExitInfo2 field of the GHCB.

Return values

0	VMGEXIT succeeded.

Returns

Exception number to be propagated, VMGEXIT processing did not succeed.

EFI_STATUS EFIAPI VmgExitHandleVc	(	IN OUT EFI_EXCEPTION_TYPE *	ExceptionType,
		IN OUT EFI_SYSTEM_CONTEXT	SystemContext
	)

Handle a #VC exception.

Performs the necessary processing to handle a #VC exception.

The base library function returns an error equal to VC_EXCEPTION, to be propagated to the standard exception handling stack.

Parameters

[in,out]	ExceptionType	Pointer to an EFI_EXCEPTION_TYPE to be set as value to use on error.
[in,out]	SystemContext	Pointer to EFI_SYSTEM_CONTEXT

Return values

EFI_SUCCESS	Exception handled
EFI_UNSUPPORTED	#VC not supported, (new) exception value to propagate provided
EFI_PROTOCOL_ERROR	#VC handling failed, (new) exception value to propagate provided

VOID EFIAPI VmgInit	(	IN OUT GHCB *	Ghcb,
		IN OUT BOOLEAN *	InterruptState
	)

Perform pre-VMGEXIT initialization/preparation.

Performs the necessary steps in preparation for invoking VMGEXIT. Must be called before setting any fields within the GHCB.

Parameters

[in,out]	Ghcb	A pointer to the GHCB
[in,out]	InterruptState	A pointer to hold the current interrupt state, used for restoring in VmgDone ()

BOOLEAN EFIAPI VmgIsOffsetValid	(	IN GHCB *	Ghcb,
		IN GHCB_REGISTER	Offset
	)

Checks if a specified offset is valid in the GHCB.

The ValidBitmap area represents the areas of the GHCB that have been marked valid. Return whether the bit in the ValidBitmap is set for the input offset.

Parameters

[in]	Ghcb	A pointer to the GHCB
[in]	Offset	Qword offset in the GHCB to mark valid

Return values

TRUE	Offset is marked valid in the GHCB
FALSE	Offset is not marked valid in the GHCB

VOID EFIAPI VmgSetOffsetValid	(	IN OUT GHCB *	Ghcb,
		IN GHCB_REGISTER	Offset
	)

Marks a specified offset as valid in the GHCB.

The ValidBitmap area represents the areas of the GHCB that have been marked valid. Set the bit in ValidBitmap for the input offset.

Parameters

[in,out]	Ghcb	A pointer to the GHCB
[in]	Offset	Qword offset in the GHCB to mark valid