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| author | Laszlo Ersek <lersek@redhat.com> | 2018-03-01 17:31:44 +0100 |
|---|---|---|
| committer | Laszlo Ersek <lersek@redhat.com> | 2018-03-06 13:30:30 +0100 |
| commit | 61a044c6c15f5806a30ff23409ba5287d9d07163 (patch) | |
| tree | 028384126c251dabd3ad2005e7d9472385496187 /OvmfPkg | |
| parent | cd66bd73169fd8cd094887febab03a196d1bd996 (diff) | |
| download | edk2-61a044c6c15f5806a30ff23409ba5287d9d07163.tar.gz | |
OvmfPkg/MemEncryptSevLib: find pages of initial SMRAM save state map
In the next three patches, we're going to modify three modules under
OvmfPkg. When OVMF is built with -D SMM_REQUIRE and runs in an SEV guest,
each affected module will have to know the page range that covers the
initial (pre-SMBASE relocation) SMRAM save state map. Add a helper
function to MemEncryptSevLib that calculates the "base address" and
"number of pages" constants for this page range.
(In a RELEASE build -- i.e., with assertions disabled and optimization
enabled --, the helper function can be compiled to store two constants
determined at compile time.)
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Diffstat (limited to 'OvmfPkg')
3 files changed, 78 insertions, 0 deletions
diff --git a/OvmfPkg/Include/Library/MemEncryptSevLib.h b/OvmfPkg/Include/Library/MemEncryptSevLib.h index e5ebb44018..1e2ec8641d 100644 --- a/OvmfPkg/Include/Library/MemEncryptSevLib.h +++ b/OvmfPkg/Include/Library/MemEncryptSevLib.h @@ -86,4 +86,27 @@ MemEncryptSevSetPageEncMask ( IN UINTN NumPages,
IN BOOLEAN Flush
);
+
+
+/**
+ Locate the page range that covers the initial (pre-SMBASE-relocation) SMRAM
+ Save State Map.
+
+ @param[out] BaseAddress The base address of the lowest-address page that
+ covers the initial SMRAM Save State Map.
+
+ @param[out] NumberOfPages The number of pages in the page range that covers
+ the initial SMRAM Save State Map.
+
+ @retval RETURN_SUCCESS BaseAddress and NumberOfPages have been set on
+ output.
+
+ @retval RETURN_UNSUPPORTED SMM is unavailable.
+**/
+RETURN_STATUS
+EFIAPI
+MemEncryptSevLocateInitialSmramSaveStateMapPages (
+ OUT UINTN *BaseAddress,
+ OUT UINTN *NumberOfPages
+ );
#endif // _MEM_ENCRYPT_SEV_LIB_H_
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/BaseMemEncryptSevLib.inf b/OvmfPkg/Library/BaseMemEncryptSevLib/BaseMemEncryptSevLib.inf index 2f0a2392a7..464fe1f33e 100644 --- a/OvmfPkg/Library/BaseMemEncryptSevLib/BaseMemEncryptSevLib.inf +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/BaseMemEncryptSevLib.inf @@ -51,3 +51,7 @@ CpuLib
DebugLib
MemoryAllocationLib
+ PcdLib
+
+[FeaturePcd]
+ gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/MemEncryptSevLibInternal.c b/OvmfPkg/Library/BaseMemEncryptSevLib/MemEncryptSevLibInternal.c index 7078ab0d3f..b92ba50c61 100644 --- a/OvmfPkg/Library/BaseMemEncryptSevLib/MemEncryptSevLibInternal.c +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/MemEncryptSevLibInternal.c @@ -17,9 +17,13 @@ #include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/MemEncryptSevLib.h>
+#include <Library/PcdLib.h>
#include <Register/Amd/Cpuid.h>
#include <Register/Amd/Msr.h>
#include <Register/Cpuid.h>
+#include <Register/QemuSmramSaveStateMap.h>
+#include <Register/SmramSaveStateMap.h>
+#include <Uefi/UefiBaseType.h>
STATIC BOOLEAN mSevStatus = FALSE;
STATIC BOOLEAN mSevStatusChecked = FALSE;
@@ -87,3 +91,50 @@ MemEncryptSevIsEnabled ( return mSevStatus;
}
+
+
+/**
+ Locate the page range that covers the initial (pre-SMBASE-relocation) SMRAM
+ Save State Map.
+
+ @param[out] BaseAddress The base address of the lowest-address page that
+ covers the initial SMRAM Save State Map.
+
+ @param[out] NumberOfPages The number of pages in the page range that covers
+ the initial SMRAM Save State Map.
+
+ @retval RETURN_SUCCESS BaseAddress and NumberOfPages have been set on
+ output.
+
+ @retval RETURN_UNSUPPORTED SMM is unavailable.
+**/
+RETURN_STATUS
+EFIAPI
+MemEncryptSevLocateInitialSmramSaveStateMapPages (
+ OUT UINTN *BaseAddress,
+ OUT UINTN *NumberOfPages
+ )
+{
+ UINTN MapStart;
+ UINTN MapEnd;
+ UINTN MapPagesStart; // MapStart rounded down to page boundary
+ UINTN MapPagesEnd; // MapEnd rounded up to page boundary
+ UINTN MapPagesSize; // difference between MapPagesStart and MapPagesEnd
+
+ if (!FeaturePcdGet (PcdSmmSmramRequire)) {
+ return RETURN_UNSUPPORTED;
+ }
+
+ MapStart = SMM_DEFAULT_SMBASE + SMRAM_SAVE_STATE_MAP_OFFSET;
+ MapEnd = MapStart + sizeof (QEMU_SMRAM_SAVE_STATE_MAP);
+ MapPagesStart = MapStart & ~(UINTN)EFI_PAGE_MASK;
+ MapPagesEnd = ALIGN_VALUE (MapEnd, EFI_PAGE_SIZE);
+ MapPagesSize = MapPagesEnd - MapPagesStart;
+
+ ASSERT ((MapPagesSize & EFI_PAGE_MASK) == 0);
+
+ *BaseAddress = MapPagesStart;
+ *NumberOfPages = MapPagesSize >> EFI_PAGE_SHIFT;
+
+ return RETURN_SUCCESS;
+}
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