OvmfPkg/VmgExitLib: Implement library support for VmgExitLib in OVMF

The base VmgExitLib library provides a default limited interface. As it
does not provide full support, create an OVMF version of this library to
begin the process of providing full support of SEV-ES within OVMF.

SEV-ES support is only provided for X64 builds, so only OvmfPkgX64.dsc is
updated to make use of the OvmfPkg version of the library.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
This commit is contained in:
Tom Lendacky
2020-08-12 15:21:36 -05:00
committed by mergify[bot]
parent 5277540e37
commit 61bacc0fa1
4 changed files with 277 additions and 1 deletions

View File

@@ -0,0 +1,81 @@
/** @file
X64 #VC Exception Handler functon.
Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Base.h>
#include <Uefi.h>
#include <Library/BaseMemoryLib.h>
#include <Library/VmgExitLib.h>
#include <Register/Amd/Msr.h>
/**
Handle a #VC exception.
Performs the necessary processing to handle a #VC exception.
@param[in, out] ExceptionType Pointer to an EFI_EXCEPTION_TYPE to be set
as value to use on error.
@param[in, out] SystemContext Pointer to EFI_SYSTEM_CONTEXT
@retval EFI_SUCCESS Exception handled
@retval EFI_UNSUPPORTED #VC not supported, (new) exception value to
propagate provided
@retval EFI_PROTOCOL_ERROR #VC handling failed, (new) exception value to
propagate provided
**/
EFI_STATUS
EFIAPI
VmgExitHandleVc (
IN OUT EFI_EXCEPTION_TYPE *ExceptionType,
IN OUT EFI_SYSTEM_CONTEXT SystemContext
)
{
MSR_SEV_ES_GHCB_REGISTER Msr;
EFI_SYSTEM_CONTEXT_X64 *Regs;
GHCB *Ghcb;
UINT64 ExitCode, Status;
EFI_STATUS VcRet;
VcRet = EFI_SUCCESS;
Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
ASSERT (Msr.GhcbInfo.Function == 0);
ASSERT (Msr.Ghcb != 0);
Regs = SystemContext.SystemContextX64;
Ghcb = Msr.Ghcb;
VmgInit (Ghcb);
ExitCode = Regs->ExceptionData;
switch (ExitCode) {
default:
Status = VmgExit (Ghcb, SVM_EXIT_UNSUPPORTED, ExitCode, 0);
if (Status == 0) {
Regs->ExceptionData = 0;
*ExceptionType = GP_EXCEPTION;
} else {
GHCB_EVENT_INJECTION Event;
Event.Uint64 = Status;
if (Event.Elements.ErrorCodeValid != 0) {
Regs->ExceptionData = Event.Elements.ErrorCode;
} else {
Regs->ExceptionData = 0;
}
*ExceptionType = Event.Elements.Vector;
}
VcRet = EFI_PROTOCOL_ERROR;
}
VmgDone (Ghcb);
return VcRet;
}