On 5/20/22 10:27, Michael Roth wrote:
A full-featured SEV-SNP guest will not rely on the AP jump table, and
will instead use the AP Creation interface defined by the GHCB. However,
a guest is still allowed to use the AP jump table if desired.
However, unlike with SEV-ES guests, SEV-SNP guests should not
store/retrieve the jump table address via GHCB requests to the
hypervisor, they should instead store/retrieve it via the SEV-SNP
secrets page. Implement the store side of this for OVMF.
Suggested-by: Tom Lendacky <thomas.lenda...@amd.com>
Signed-off-by: Michael Roth <michael.r...@amd.com>
---
UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf | 1 +
UefiCpuPkg/Library/MpInitLib/DxeMpLib.c | 10 ++++++++++
2 files changed, 11 insertions(+)
diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
index e1cd0b3500..d8cfddcd82 100644
--- a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
+++ b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
@@ -80,3 +80,4 @@
gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard ##
CONSUMES
gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbBase ##
CONSUMES
gEfiMdePkgTokenSpaceGuid.PcdConfidentialComputingGuestAttr ##
CONSUMES
+ gEfiMdePkgTokenSpaceGuid.PcdSevSnpSecretsAddress ##
CONSUMES
diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
index 60d14a5a0e..4d6f7643db 100644
--- a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
@@ -15,6 +15,7 @@
#include <Library/VmgExitLib.h>
#include <Register/Amd/Fam17Msr.h>
#include <Register/Amd/Ghcb.h>
+#include <Register/Amd/SnpSecretsPage.h>
#include <Protocol/Timer.h>
@@ -216,6 +217,15 @@ GetSevEsAPMemory (
DEBUG ((DEBUG_INFO, "Dxe: SevEsAPMemory = %lx\n", (UINTN)StartAddress));
+ if (ConfidentialComputingGuestHas (CCAttrAmdSevSnp)) {
+ SNP_SECRETS_PAGE *Secrets;
+
+ Secrets = (SNP_SECRETS_PAGE *)(INTN)PcdGet64
(PcdSevSnpSecretsAddress);
+ Secrets->OsArea.ApJumpTablePa = (UINT64)(UINTN)StartAddress;
+
+ return (UINTN)StartAddress;
+ }
+
Just a nit, but I probably would have still put this under the comment
below, because you are still saving the SevEsAPMemory as the AP jump table.
It might look cleaner with the non-SNP path as the else and have the
single return.
Probably not worth another version, but up to you.
Thanks,
Tom
//
// Save the SevEsAPMemory as the AP jump table.
//
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