[PATCH v4 3/4] OvmfPkg/PlatformPei: Mark SEC GHCB page as unencrypted via hypercall


Ashish Kalra
 

From: Ashish Kalra <ashish.kalra@amd.com>

Mark the SEC GHCB page (that is mapped as unencrypted in
ResetVector code) in the hypervisor page status tracking.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
OvmfPkg/PlatformPei/AmdSev.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/OvmfPkg/PlatformPei/AmdSev.c b/OvmfPkg/PlatformPei/AmdSev.c
index a8bf610022..3f642ecb06 100644
--- a/OvmfPkg/PlatformPei/AmdSev.c
+++ b/OvmfPkg/PlatformPei/AmdSev.c
@@ -15,6 +15,7 @@
#include <Library/HobLib.h>
#include <Library/MemEncryptSevLib.h>
#include <Library/MemoryAllocationLib.h>
+#include <Library/MemEncryptHypercallLib.h>
#include <Library/PcdLib.h>
#include <PiPei.h>
#include <Register/Amd/Msr.h>
@@ -52,6 +53,15 @@ AmdSevEsInitialize (
PcdStatus = PcdSetBoolS (PcdSevEsIsEnabled, TRUE);
ASSERT_RETURN_ERROR (PcdStatus);

+ //
+ // GHCB_BASE setup during reset-vector needs to be marked as
+ // decrypted in the hypervisor page encryption bitmap.
+ //
+ SetMemoryEncDecHypercall3 (FixedPcdGet32 (PcdOvmfSecGhcbBase),
+ EFI_SIZE_TO_PAGES(FixedPcdGet32 (PcdOvmfSecGhcbSize)),
+ KVM_MAP_GPA_RANGE_DECRYPTED
+ );
+
//
// Allocate GHCB and per-CPU variable pages.
// Since the pages must survive across the UEFI to OS transition
--
2.17.1

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