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OvmfPkg/MemEncryptSevLib: change the page state in the RMP table 

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275

The MemEncryptSev{Set,Clear}PageEncMask() functions are used to set or
clear the memory encryption attribute in the page table. When SEV-SNP
is active, we also need to change the page state in the RMP table so that
it is in sync with the memory encryption attribute change.

Cc: Michael Roth <michael.roth@amd.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Min Xu <min.m.xu@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Jiewen Yao <Jiewen.yao@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
This commit is contained in:
Brijesh Singh via groups.io 2021-12-09 11:27:56 +08:00 committed by mergify[bot]
parent d4d7c9ad5f
commit b928eb44d5
1 changed files with 34 additions and 0 deletions
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34
OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
View File

@ -17,6 +17,7 @@
#include <Register/Cpuid.h>
#include "VirtualMemory.h"
#include "SnpPageStateChange.h"
STATIC BOOLEAN mAddressEncMaskChecked = FALSE;
STATIC UINT64 mAddressEncMask;
@ -693,10 +694,12 @@ SetMemoryEncDec (
PAGE_MAP_AND_DIRECTORY_POINTER *PageDirectoryPointerEntry;
PAGE_TABLE_1G_ENTRY *PageDirectory1GEntry;
PAGE_TABLE_ENTRY *PageDirectory2MEntry;
PHYSICAL_ADDRESS OrigPhysicalAddress;
PAGE_TABLE_4K_ENTRY *PageTableEntry;
UINT64 PgTableMask;
UINT64 AddressEncMask;
BOOLEAN IsWpEnabled;
UINTN OrigLength;
RETURN_STATUS Status;
//
@ -749,6 +752,22 @@ SetMemoryEncDec (
Status = EFI_SUCCESS;
//
// To maintain the security gurantees we must set the page to shared in the RMP
// table before clearing the memory encryption mask from the current page table.
//
// The InternalSetPageState() is used for setting the page state in the RMP table.
//
if ((Mode == ClearCBit) && MemEncryptSevSnpIsEnabled ()) {
InternalSetPageState (PhysicalAddress, EFI_SIZE_TO_PAGES (Length), SevSnpPageShared, FALSE);
}
//
// Save the specified length and physical address (we need it later).
//
OrigLength = Length;
OrigPhysicalAddress = PhysicalAddress;
while (Length != 0) {
//
// If Cr3BaseAddress is not specified then read the current CR3
@ -922,6 +941,21 @@ SetMemoryEncDec (
//
CpuFlushTlb ();
//
// SEV-SNP requires that all the private pages (i.e pages mapped encrypted) must be
// added in the RMP table before the access.
//
// The InternalSetPageState() is used for setting the page state in the RMP table.
//
if ((Mode == SetCBit) && MemEncryptSevSnpIsEnabled ()) {
InternalSetPageState (
OrigPhysicalAddress,
EFI_SIZE_TO_PAGES (OrigLength),
SevSnpPagePrivate,
FALSE
);
}
Done:
//
// Restore page table write protection, if any.