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.biesheu...@linaro.org>
Cc: Brijesh Singh <brijesh.si...@amd.com>
Cc: Jordan Justen <jordan.l.jus...@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <ler...@redhat.com>
---
OvmfPkg/Library/BaseMemEncryptSevLib/BaseMemEncryptSevLib.inf | 4 ++
OvmfPkg/Include/Library/MemEncryptSevLib.h | 23 +++++++++
OvmfPkg/Library/BaseMemEncryptSevLib/MemEncryptSevLibInternal.c | 51
++++++++++++++++++++
3 files changed, 78 insertions(+)
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/BaseMemEncryptSevLib.inf
b/OvmfPkg/Library/BaseMemEncryptSevLib/BaseMemEncryptSevLib.inf
index 2f0a2392a7ad..464fe1f33e66 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/BaseMemEncryptSevLib.inf
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/BaseMemEncryptSevLib.inf
@@ -34,20 +34,24 @@ [Packages]
MdeModulePkg/MdeModulePkg.dec
MdePkg/MdePkg.dec
OvmfPkg/OvmfPkg.dec
UefiCpuPkg/UefiCpuPkg.dec
[Sources.X64]
MemEncryptSevLibInternal.c
X64/MemEncryptSevLib.c
X64/VirtualMemory.c
[Sources.IA32]
Ia32/MemEncryptSevLib.c
MemEncryptSevLibInternal.c
[LibraryClasses]
BaseLib
CacheMaintenanceLib
CpuLib
DebugLib
MemoryAllocationLib
+ PcdLib
+
+[FeaturePcd]
+ gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire
diff --git a/OvmfPkg/Include/Library/MemEncryptSevLib.h
b/OvmfPkg/Include/Library/MemEncryptSevLib.h
index e5ebb4401818..1e2ec8641d46 100644
--- a/OvmfPkg/Include/Library/MemEncryptSevLib.h
+++ b/OvmfPkg/Include/Library/MemEncryptSevLib.h
@@ -69,21 +69,44 @@ MemEncryptSevClearPageEncMask (
address of a memory region.
@param[in] NumPages The number of pages from start memory
region.
@param[in] Flush Flush the caches before setting the bit
(mostly TRUE except MMIO addresses)
@retval RETURN_SUCCESS The attributes were set for the memory
region.
@retval RETURN_INVALID_PARAMETER Number of pages is zero.
@retval RETURN_UNSUPPORTED Setting the memory encryption attribute
is not supported
**/
RETURN_STATUS
EFIAPI
MemEncryptSevSetPageEncMask (
IN PHYSICAL_ADDRESS Cr3BaseAddress,
IN PHYSICAL_ADDRESS BaseAddress,
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/MemEncryptSevLibInternal.c
b/OvmfPkg/Library/BaseMemEncryptSevLib/MemEncryptSevLibInternal.c
index 7078ab0d3f46..b92ba50c616c 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/MemEncryptSevLibInternal.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/MemEncryptSevLibInternal.c
@@ -1,42 +1,46 @@
/** @file
Secure Encrypted Virtualization (SEV) library helper function
Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
This program and the accompanying materials are licensed and made available
under the terms and conditions of the BSD License which accompanies this
distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#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;
/**
Returns a boolean to indicate whether SEV is enabled
@retval TRUE SEV is enabled
@retval FALSE SEV is not enabled
**/
STATIC
BOOLEAN
EFIAPI
InternalMemEncryptSevIsEnabled (
VOID
)
{
UINT32 RegEax;
MSR_SEV_STATUS_REGISTER Msr;
@@ -70,20 +74,67 @@ InternalMemEncryptSevIsEnabled (
Returns a boolean to indicate whether SEV is enabled
@retval TRUE SEV is enabled
@retval FALSE SEV is not enabled
**/
BOOLEAN
EFIAPI
MemEncryptSevIsEnabled (
VOID
)
{
if (mSevStatusChecked) {
return mSevStatus;
}
mSevStatus = InternalMemEncryptSevIsEnabled();
mSevStatusChecked = TRUE;
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;
+}
--
2.14.1.3.gb7cf6e02401b
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