diff options
| -rw-r--r-- | UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c index 509be9b417..c9f0984f41 100644 --- a/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c +++ b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c @@ -13,6 +13,8 @@ #include <Register/Amd/Fam17Msr.h>
#include <Register/Amd/Ghcb.h>
+#define _IS_ALIGNED(x, y) (ALIGN_POINTER((x), (y)) == (x))
+
/**
Perform the requested AP Creation action.
@@ -121,6 +123,7 @@ SevSnpCreateSaveArea ( UINT32 ApicId
)
{
+ UINT8 *Pages;
SEV_ES_SAVE_AREA *SaveArea;
IA32_CR0 ApCr0;
IA32_CR0 ResetCr0;
@@ -131,13 +134,30 @@ SevSnpCreateSaveArea ( if (CpuData->SevEsSaveArea == NULL) {
//
- // Allocate a single page for the SEV-ES Save Area and initialize it.
+ // Allocate a page for the SEV-ES Save Area and initialize it. Due to AMD
+ // erratum #1467 (VMSA cannot be on a 2MB boundary), allocate an extra page
+ // to choose from to work around the issue.
//
- SaveArea = AllocateReservedPages (1);
- if (!SaveArea) {
+ Pages = AllocateReservedPages (2);
+ if (!Pages) {
return;
}
+ //
+ // Since page allocation works by allocating downward in the address space,
+ // try to always free the first (lower address) page to limit possible holes
+ // in the memory map. So, if the address of the second page is 2MB aligned,
+ // then use the first page and free the second page. Otherwise, free the
+ // first page and use the second page.
+ //
+ if (_IS_ALIGNED (Pages + EFI_PAGE_SIZE, SIZE_2MB)) {
+ SaveArea = (SEV_ES_SAVE_AREA *)Pages;
+ FreePages (Pages + EFI_PAGE_SIZE, 1);
+ } else {
+ SaveArea = (SEV_ES_SAVE_AREA *)(Pages + EFI_PAGE_SIZE);
+ FreePages (Pages, 1);
+ }
+
CpuData->SevEsSaveArea = SaveArea;
} else {
SaveArea = CpuData->SevEsSaveArea;
|