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OvmfPkg/PlatformPei: register GHCB gpa for the SEV-SNP guest

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BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275

The SEV-SNP guest requires that GHCB GPA must be registered before using.
See the GHCB specification section 2.3.2 for more details.

Cc: Michael Roth <michael.roth@amd.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Min Xu <min.m.xu@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Jiewen Yao <Jiewen.yao@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
This commit is contained in:
Brijesh Singh 2021-12-09 11:27:40 +08:00 committed by mergify[bot]
parent d2b998fbdc
commit a19b648952
1 changed files with 88 additions and 0 deletions
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88
OvmfPkg/PlatformPei/AmdSev.c
View File

@ -19,9 +19,90 @@
#include <PiPei.h> #include <PiPei.h>
#include <Register/Amd/Msr.h> #include <Register/Amd/Msr.h>
#include <Register/Intel/SmramSaveStateMap.h> #include <Register/Intel/SmramSaveStateMap.h>
#include <Library/VmgExitLib.h>
#include "Platform.h" #include "Platform.h"
/**
Handle an SEV-SNP/GHCB protocol check failure.
Notify the hypervisor using the VMGEXIT instruction that the SEV-SNP guest
wishes to be terminated.
@param[in] ReasonCode Reason code to provide to the hypervisor for the
termination request.
**/
STATIC
VOID
SevEsProtocolFailure (
IN UINT8 ReasonCode
)
{
MSR_SEV_ES_GHCB_REGISTER Msr;
//
// Use the GHCB MSR Protocol to request termination by the hypervisor
//
Msr.GhcbPhysicalAddress = 0;
Msr.GhcbTerminate.Function = GHCB_INFO_TERMINATE_REQUEST;
Msr.GhcbTerminate.ReasonCodeSet = GHCB_TERMINATE_GHCB;
Msr.GhcbTerminate.ReasonCode = ReasonCode;
AsmWriteMsr64 (MSR_SEV_ES_GHCB, Msr.GhcbPhysicalAddress);
AsmVmgExit ();
ASSERT (FALSE);
CpuDeadLoop ();
}
/**
This function can be used to register the GHCB GPA.
@param[in] Address The physical address to be registered.
**/
STATIC
VOID
GhcbRegister (
IN EFI_PHYSICAL_ADDRESS Address
)
{
MSR_SEV_ES_GHCB_REGISTER Msr;
MSR_SEV_ES_GHCB_REGISTER CurrentMsr;
//
// Save the current MSR Value
//
CurrentMsr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
//
// Use the GHCB MSR Protocol to request to register the GPA.
//
Msr.GhcbPhysicalAddress = Address & ~EFI_PAGE_MASK;
Msr.GhcbGpaRegister.Function = GHCB_INFO_GHCB_GPA_REGISTER_REQUEST;
AsmWriteMsr64 (MSR_SEV_ES_GHCB, Msr.GhcbPhysicalAddress);
AsmVmgExit ();
Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
//
// If hypervisor responded with a different GPA than requested then fail.
//
if ((Msr.GhcbGpaRegister.Function != GHCB_INFO_GHCB_GPA_REGISTER_RESPONSE) ||
((Msr.GhcbPhysicalAddress & ~EFI_PAGE_MASK) != Address))
{
SevEsProtocolFailure (GHCB_TERMINATE_GHCB_GENERAL);
}
//
// Restore the MSR
//
AsmWriteMsr64 (MSR_SEV_ES_GHCB, CurrentMsr.GhcbPhysicalAddress);
}
/** /**
Initialize SEV-ES support if running as an SEV-ES guest. Initialize SEV-ES support if running as an SEV-ES guest.
@ -115,6 +196,13 @@ AmdSevEsInitialize (
GhcbBackupBase GhcbBackupBase
)); ));
//
// SEV-SNP guest requires that GHCB GPA must be registered before using it.
//
if (MemEncryptSevSnpIsEnabled ()) {
GhcbRegister (GhcbBasePa);
}
AsmWriteMsr64 (MSR_SEV_ES_GHCB, GhcbBasePa); AsmWriteMsr64 (MSR_SEV_ES_GHCB, GhcbBasePa);
// //