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c0984d1ff28325a8f1c76e23a79141cbb12c3e4f
system76-edk2/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
Brijesh Singh b7b8872031 OvmfPkg/MemEncryptSevLib: skip page state change for Mmio address 
The SetMemoryEncDec() is used by the higher level routines to set or clear
the page encryption mask for system RAM and Mmio address. When SEV-SNP is
active, in addition to set/clear page mask it also updates the RMP table.
The RMP table updates are required for the system RAM address and not
the Mmio address.

Add a new parameter in SetMemoryEncDec() to tell whether the specified
address is Mmio. If its Mmio then skip the page state change in the RMP
table.

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: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Jiewen Yao <Jiewen.yao@intel.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
2021-12-09 06:28:10 +00:00

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/** @file
Virtual Memory Management Services to set or clear the memory encryption bit
Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2017 - 2020, AMD Incorporated. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
Code is derived from MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
**/
#include <Library/CpuLib.h>
#include <Library/MemEncryptSevLib.h>
#include <Register/Amd/Cpuid.h>
#include <Register/Cpuid.h>
#include "VirtualMemory.h"
#include "SnpPageStateChange.h"
STATIC BOOLEAN mAddressEncMaskChecked = FALSE;
STATIC UINT64 mAddressEncMask;
STATIC PAGE_TABLE_POOL *mPageTablePool = NULL;
typedef enum {
SetCBit,
ClearCBit
} MAP_RANGE_MODE;
/**
Return the pagetable memory encryption mask.
@return The pagetable memory encryption mask.
**/
UINT64
EFIAPI
InternalGetMemEncryptionAddressMask (
VOID
)
{
UINT64 EncryptionMask;
if (mAddressEncMaskChecked) {
return mAddressEncMask;
}
EncryptionMask = MemEncryptSevGetEncryptionMask ();
mAddressEncMask = EncryptionMask & PAGING_1G_ADDRESS_MASK_64;
mAddressEncMaskChecked = TRUE;
return mAddressEncMask;
}
/**
Initialize a buffer pool for page table use only.
To reduce the potential split operation on page table, the pages reserved for
page table should be allocated in the times of PAGE_TABLE_POOL_UNIT_PAGES and
at the boundary of PAGE_TABLE_POOL_ALIGNMENT. So the page pool is always
initialized with number of pages greater than or equal to the given
PoolPages.
Once the pages in the pool are used up, this method should be called again to
reserve at least another PAGE_TABLE_POOL_UNIT_PAGES. Usually this won't
happen often in practice.
@param[in] PoolPages The least page number of the pool to be created.
@retval TRUE The pool is initialized successfully.
@retval FALSE The memory is out of resource.
**/
STATIC
BOOLEAN
InitializePageTablePool (
IN UINTN PoolPages
)
{
VOID *Buffer;
//
// Always reserve at least PAGE_TABLE_POOL_UNIT_PAGES, including one page for
// header.
//
PoolPages += 1; // Add one page for header.
PoolPages = ((PoolPages - 1) / PAGE_TABLE_POOL_UNIT_PAGES + 1) *
PAGE_TABLE_POOL_UNIT_PAGES;
Buffer = AllocateAlignedPages (PoolPages, PAGE_TABLE_POOL_ALIGNMENT);
if (Buffer == NULL) {
DEBUG ((DEBUG_ERROR, "ERROR: Out of aligned pages\r\n"));
return FALSE;
}
//
// Link all pools into a list for easier track later.
//
if (mPageTablePool == NULL) {
mPageTablePool = Buffer;
mPageTablePool->NextPool = mPageTablePool;
} else {
((PAGE_TABLE_POOL *)Buffer)->NextPool = mPageTablePool->NextPool;
mPageTablePool->NextPool = Buffer;
mPageTablePool = Buffer;
}
//
// Reserve one page for pool header.
//
mPageTablePool->FreePages = PoolPages - 1;
mPageTablePool->Offset = EFI_PAGES_TO_SIZE (1);
return TRUE;
}
/**
This API provides a way to allocate memory for page table.
This API can be called more than once to allocate memory for page tables.
Allocates the number of 4KB pages and returns a pointer to the allocated
buffer. The buffer returned is aligned on a 4KB boundary.
If Pages is 0, then NULL is returned.
If there is not enough memory remaining to satisfy the request, then NULL is
returned.
@param Pages The number of 4 KB pages to allocate.
@return A pointer to the allocated buffer or NULL if allocation fails.
**/
STATIC
VOID *
EFIAPI
AllocatePageTableMemory (
IN UINTN Pages
)
{
VOID *Buffer;
if (Pages == 0) {
return NULL;
}
//
// Renew the pool if necessary.
//
if ((mPageTablePool == NULL) ||
(Pages > mPageTablePool->FreePages))
{
if (!InitializePageTablePool (Pages)) {
return NULL;
}
}
Buffer = (UINT8 *)mPageTablePool + mPageTablePool->Offset;
mPageTablePool->Offset += EFI_PAGES_TO_SIZE (Pages);
mPageTablePool->FreePages -= Pages;
DEBUG ((
DEBUG_VERBOSE,
"%a:%a: Buffer=0x%Lx Pages=%ld\n",
gEfiCallerBaseName,
__FUNCTION__,
Buffer,
Pages
));
return Buffer;
}
/**
Split 2M page to 4K.
@param[in] PhysicalAddress Start physical address the 2M page
covered.
@param[in, out] PageEntry2M Pointer to 2M page entry.
@param[in] StackBase Stack base address.
@param[in] StackSize Stack size.
**/
STATIC
VOID
Split2MPageTo4K (
IN PHYSICAL_ADDRESS PhysicalAddress,
IN OUT UINT64 *PageEntry2M,
IN PHYSICAL_ADDRESS StackBase,
IN UINTN StackSize
)
{
PHYSICAL_ADDRESS PhysicalAddress4K;
UINTN IndexOfPageTableEntries;
PAGE_TABLE_4K_ENTRY *PageTableEntry;
PAGE_TABLE_4K_ENTRY *PageTableEntry1;
UINT64 AddressEncMask;
PageTableEntry = AllocatePageTableMemory (1);
PageTableEntry1 = PageTableEntry;
AddressEncMask = InternalGetMemEncryptionAddressMask ();
ASSERT (PageTableEntry != NULL);
ASSERT (*PageEntry2M & AddressEncMask);
PhysicalAddress4K = PhysicalAddress;
for (IndexOfPageTableEntries = 0;
IndexOfPageTableEntries < 512;
(IndexOfPageTableEntries++,
PageTableEntry++,
PhysicalAddress4K += SIZE_4KB))
{
//
// Fill in the Page Table entries
//
PageTableEntry->Uint64 = (UINT64)PhysicalAddress4K | AddressEncMask;
PageTableEntry->Bits.ReadWrite = 1;
PageTableEntry->Bits.Present = 1;
if ((PhysicalAddress4K >= StackBase) &&
(PhysicalAddress4K < StackBase + StackSize))
{
//
// Set Nx bit for stack.
//
PageTableEntry->Bits.Nx = 1;
}
}
//
// Fill in 2M page entry.
//
*PageEntry2M = ((UINT64)(UINTN)PageTableEntry1 |
IA32_PG_P | IA32_PG_RW | AddressEncMask);
}
/**
Set one page of page table pool memory to be read-only.
@param[in] PageTableBase Base address of page table (CR3).
@param[in] Address Start address of a page to be set as read-only.
@param[in] Level4Paging Level 4 paging flag.
**/
STATIC
VOID
SetPageTablePoolReadOnly (
IN UINTN PageTableBase,
IN EFI_PHYSICAL_ADDRESS Address,
IN BOOLEAN Level4Paging
)
{
UINTN Index;
UINTN EntryIndex;
UINT64 AddressEncMask;
EFI_PHYSICAL_ADDRESS PhysicalAddress;
UINT64 *PageTable;
UINT64 *NewPageTable;
UINT64 PageAttr;
UINT64 LevelSize[5];
UINT64 LevelMask[5];
UINTN LevelShift[5];
UINTN Level;
UINT64 PoolUnitSize;
ASSERT (PageTableBase != 0);
//
// Since the page table is always from page table pool, which is always
// located at the boundary of PcdPageTablePoolAlignment, we just need to
// set the whole pool unit to be read-only.
//
Address = Address & PAGE_TABLE_POOL_ALIGN_MASK;
LevelShift[1] = PAGING_L1_ADDRESS_SHIFT;
LevelShift[2] = PAGING_L2_ADDRESS_SHIFT;
LevelShift[3] = PAGING_L3_ADDRESS_SHIFT;
LevelShift[4] = PAGING_L4_ADDRESS_SHIFT;
LevelMask[1] = PAGING_4K_ADDRESS_MASK_64;
LevelMask[2] = PAGING_2M_ADDRESS_MASK_64;
LevelMask[3] = PAGING_1G_ADDRESS_MASK_64;
LevelMask[4] = PAGING_1G_ADDRESS_MASK_64;
LevelSize[1] = SIZE_4KB;
LevelSize[2] = SIZE_2MB;
LevelSize[3] = SIZE_1GB;
LevelSize[4] = SIZE_512GB;
AddressEncMask = InternalGetMemEncryptionAddressMask ();
PageTable = (UINT64 *)(UINTN)PageTableBase;
PoolUnitSize = PAGE_TABLE_POOL_UNIT_SIZE;
for (Level = (Level4Paging) ? 4 : 3; Level > 0; --Level) {
Index = ((UINTN)RShiftU64 (Address, LevelShift[Level]));
Index &= PAGING_PAE_INDEX_MASK;
PageAttr = PageTable[Index];
if ((PageAttr & IA32_PG_PS) == 0) {
//
// Go to next level of table.
//
PageTable = (UINT64 *)(UINTN)(PageAttr & ~AddressEncMask &
PAGING_4K_ADDRESS_MASK_64);
continue;
}
if (PoolUnitSize >= LevelSize[Level]) {
//
// Clear R/W bit if current page granularity is not larger than pool unit
// size.
//
if ((PageAttr & IA32_PG_RW) != 0) {
while (PoolUnitSize > 0) {
//
// PAGE_TABLE_POOL_UNIT_SIZE and PAGE_TABLE_POOL_ALIGNMENT are fit in
// one page (2MB). Then we don't need to update attributes for pages
// crossing page directory. ASSERT below is for that purpose.
//
ASSERT (Index < EFI_PAGE_SIZE/sizeof (UINT64));
PageTable[Index] &= ~(UINT64)IA32_PG_RW;
PoolUnitSize -= LevelSize[Level];
++Index;
}
}
break;
} else {
//
// The smaller granularity of page must be needed.
//
ASSERT (Level > 1);
NewPageTable = AllocatePageTableMemory (1);
ASSERT (NewPageTable != NULL);
PhysicalAddress = PageAttr & LevelMask[Level];
for (EntryIndex = 0;
EntryIndex < EFI_PAGE_SIZE/sizeof (UINT64);
++EntryIndex)
{
NewPageTable[EntryIndex] = PhysicalAddress | AddressEncMask |
IA32_PG_P | IA32_PG_RW;
if (Level > 2) {
NewPageTable[EntryIndex] |= IA32_PG_PS;
}
PhysicalAddress += LevelSize[Level - 1];
}
PageTable[Index] = (UINT64)(UINTN)NewPageTable | AddressEncMask |
IA32_PG_P | IA32_PG_RW;
PageTable = NewPageTable;
}
}
}
/**
Prevent the memory pages used for page table from been overwritten.
@param[in] PageTableBase Base address of page table (CR3).
@param[in] Level4Paging Level 4 paging flag.
**/
STATIC
VOID
EnablePageTableProtection (
IN UINTN PageTableBase,
IN BOOLEAN Level4Paging
)
{
PAGE_TABLE_POOL *HeadPool;
PAGE_TABLE_POOL *Pool;
UINT64 PoolSize;
EFI_PHYSICAL_ADDRESS Address;
if (mPageTablePool == NULL) {
return;
}
//
// SetPageTablePoolReadOnly might update mPageTablePool. It's safer to
// remember original one in advance.
//
HeadPool = mPageTablePool;
Pool = HeadPool;
do {
Address = (EFI_PHYSICAL_ADDRESS)(UINTN)Pool;
PoolSize = Pool->Offset + EFI_PAGES_TO_SIZE (Pool->FreePages);
//
// The size of one pool must be multiple of PAGE_TABLE_POOL_UNIT_SIZE,
// which is one of page size of the processor (2MB by default). Let's apply
// the protection to them one by one.
//
while (PoolSize > 0) {
SetPageTablePoolReadOnly (PageTableBase, Address, Level4Paging);
Address += PAGE_TABLE_POOL_UNIT_SIZE;
PoolSize -= PAGE_TABLE_POOL_UNIT_SIZE;
}
Pool = Pool->NextPool;
} while (Pool != HeadPool);
}
/**
Split 1G page to 2M.
@param[in] PhysicalAddress Start physical address the 1G page
covered.
@param[in, out] PageEntry1G Pointer to 1G page entry.
@param[in] StackBase Stack base address.
@param[in] StackSize Stack size.
**/
STATIC
VOID
Split1GPageTo2M (
IN PHYSICAL_ADDRESS PhysicalAddress,
IN OUT UINT64 *PageEntry1G,
IN PHYSICAL_ADDRESS StackBase,
IN UINTN StackSize
)
{
PHYSICAL_ADDRESS PhysicalAddress2M;
UINTN IndexOfPageDirectoryEntries;
PAGE_TABLE_ENTRY *PageDirectoryEntry;
UINT64 AddressEncMask;
PageDirectoryEntry = AllocatePageTableMemory (1);
AddressEncMask = InternalGetMemEncryptionAddressMask ();
ASSERT (PageDirectoryEntry != NULL);
ASSERT (*PageEntry1G & AddressEncMask);
//
// Fill in 1G page entry.
//
*PageEntry1G = ((UINT64)(UINTN)PageDirectoryEntry |
IA32_PG_P | IA32_PG_RW | AddressEncMask);
PhysicalAddress2M = PhysicalAddress;
for (IndexOfPageDirectoryEntries = 0;
IndexOfPageDirectoryEntries < 512;
(IndexOfPageDirectoryEntries++,
PageDirectoryEntry++,
PhysicalAddress2M += SIZE_2MB))
{
if ((PhysicalAddress2M < StackBase + StackSize) &&
((PhysicalAddress2M + SIZE_2MB) > StackBase))
{
//
// Need to split this 2M page that covers stack range.
//
Split2MPageTo4K (
PhysicalAddress2M,
(UINT64 *)PageDirectoryEntry,
StackBase,
StackSize
);
} else {
//
// Fill in the Page Directory entries
//
PageDirectoryEntry->Uint64 = (UINT64)PhysicalAddress2M | AddressEncMask;
PageDirectoryEntry->Bits.ReadWrite = 1;
PageDirectoryEntry->Bits.Present = 1;
PageDirectoryEntry->Bits.MustBe1 = 1;
}
}
}
/**
Set or Clear the memory encryption bit
@param[in, out] PageTablePointer Page table entry pointer (PTE).
@param[in] Mode Set or Clear encryption bit
**/
STATIC VOID
SetOrClearCBit (
IN OUT UINT64 *PageTablePointer,
IN MAP_RANGE_MODE Mode
)
{
UINT64 AddressEncMask;
AddressEncMask = InternalGetMemEncryptionAddressMask ();
if (Mode == SetCBit) {
*PageTablePointer |= AddressEncMask;
} else {
*PageTablePointer &= ~AddressEncMask;
}
}
/**
Check the WP status in CR0 register. This bit is used to lock or unlock write
access to pages marked as read-only.
@retval TRUE Write protection is enabled.
@retval FALSE Write protection is disabled.
**/
STATIC
BOOLEAN
IsReadOnlyPageWriteProtected (
VOID
)
{
return ((AsmReadCr0 () & BIT16) != 0);
}
/**
Disable Write Protect on pages marked as read-only.
**/
STATIC
VOID
DisableReadOnlyPageWriteProtect (
VOID
)
{
AsmWriteCr0 (AsmReadCr0 () & ~BIT16);
}
/**
Enable Write Protect on pages marked as read-only.
**/
STATIC
VOID
EnableReadOnlyPageWriteProtect (
VOID
)
{
AsmWriteCr0 (AsmReadCr0 () | BIT16);
}
RETURN_STATUS
EFIAPI
InternalMemEncryptSevCreateIdentityMap1G (
IN PHYSICAL_ADDRESS Cr3BaseAddress,
IN PHYSICAL_ADDRESS PhysicalAddress,
IN UINTN Length
)
{
PAGE_MAP_AND_DIRECTORY_POINTER *PageMapLevel4Entry;
PAGE_TABLE_1G_ENTRY *PageDirectory1GEntry;
UINT64 PgTableMask;
UINT64 AddressEncMask;
BOOLEAN IsWpEnabled;
RETURN_STATUS Status;
//
// Set PageMapLevel4Entry to suppress incorrect compiler/analyzer warnings.
//
PageMapLevel4Entry = NULL;
DEBUG ((
DEBUG_VERBOSE,
"%a:%a: Cr3Base=0x%Lx Physical=0x%Lx Length=0x%Lx\n",
gEfiCallerBaseName,
__FUNCTION__,
Cr3BaseAddress,
PhysicalAddress,
(UINT64)Length
));
if (Length == 0) {
return RETURN_INVALID_PARAMETER;
}
//
// Check if we have a valid memory encryption mask
//
AddressEncMask = InternalGetMemEncryptionAddressMask ();
if (!AddressEncMask) {
return RETURN_ACCESS_DENIED;
}
PgTableMask = AddressEncMask | EFI_PAGE_MASK;
//
// Make sure that the page table is changeable.
//
IsWpEnabled = IsReadOnlyPageWriteProtected ();
if (IsWpEnabled) {
DisableReadOnlyPageWriteProtect ();
}
Status = EFI_SUCCESS;
while (Length) {
//
// If Cr3BaseAddress is not specified then read the current CR3
//
if (Cr3BaseAddress == 0) {
Cr3BaseAddress = AsmReadCr3 ();
}
PageMapLevel4Entry = (VOID *)(Cr3BaseAddress & ~PgTableMask);
PageMapLevel4Entry += PML4_OFFSET (PhysicalAddress);
if (!PageMapLevel4Entry->Bits.Present) {
DEBUG ((
DEBUG_ERROR,
"%a:%a: bad PML4 for Physical=0x%Lx\n",
gEfiCallerBaseName,
__FUNCTION__,
PhysicalAddress
));
Status = RETURN_NO_MAPPING;
goto Done;
}
PageDirectory1GEntry = (VOID *)(
(PageMapLevel4Entry->Bits.PageTableBaseAddress <<
12) & ~PgTableMask
);
PageDirectory1GEntry += PDP_OFFSET (PhysicalAddress);
if (!PageDirectory1GEntry->Bits.Present) {
PageDirectory1GEntry->Bits.Present = 1;
PageDirectory1GEntry->Bits.MustBe1 = 1;
PageDirectory1GEntry->Bits.MustBeZero = 0;
PageDirectory1GEntry->Bits.ReadWrite = 1;
PageDirectory1GEntry->Uint64 |= (UINT64)PhysicalAddress | AddressEncMask;
}
if (Length <= BIT30) {
Length = 0;
} else {
Length -= BIT30;
}
PhysicalAddress += BIT30;
}
//
// Flush TLB
//
CpuFlushTlb ();
Done:
//
// Restore page table write protection, if any.
//
if (IsWpEnabled) {
EnableReadOnlyPageWriteProtect ();
}
return Status;
}
/**
This function either sets or clears memory encryption bit for the memory
region specified by PhysicalAddress and Length from the current page table
context.
The function iterates through the PhysicalAddress one page at a time, and set
or clears the memory encryption mask in the page table. If it encounters
that a given physical address range is part of large page then it attempts to
change the attribute at one go (based on size), otherwise it splits the
large pages into smaller (e.g 2M page into 4K pages) and then try to set or
clear the encryption bit on the smallest page size.
@param[in] Cr3BaseAddress Cr3 Base Address (if zero then use
current CR3)
@param[in] PhysicalAddress The physical address that is the start
address of a memory region.
@param[in] Length The length of memory region
@param[in] Mode Set or Clear mode
@param[in] CacheFlush Flush the caches before applying the
encryption mask
@param[in] Mmio The physical address specified is Mmio
@retval RETURN_SUCCESS The attributes were cleared for the
memory region.
@retval RETURN_INVALID_PARAMETER Number of pages is zero.
@retval RETURN_UNSUPPORTED Setting the memory encyrption attribute
is not supported
**/
STATIC
RETURN_STATUS
EFIAPI
SetMemoryEncDec (
IN PHYSICAL_ADDRESS Cr3BaseAddress,
IN PHYSICAL_ADDRESS PhysicalAddress,
IN UINTN Length,
IN MAP_RANGE_MODE Mode,
IN BOOLEAN CacheFlush,
IN BOOLEAN Mmio
)
{
PAGE_MAP_AND_DIRECTORY_POINTER *PageMapLevel4Entry;
PAGE_MAP_AND_DIRECTORY_POINTER *PageUpperDirectoryPointerEntry;
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;
//
// Set PageMapLevel4Entry to suppress incorrect compiler/analyzer warnings.
//
PageMapLevel4Entry = NULL;
DEBUG ((
DEBUG_VERBOSE,
"%a:%a: Cr3Base=0x%Lx Physical=0x%Lx Length=0x%Lx Mode=%a CacheFlush=%u Mmio=%u\n",
gEfiCallerBaseName,
__FUNCTION__,
Cr3BaseAddress,
PhysicalAddress,
(UINT64)Length,
(Mode == SetCBit) ? "Encrypt" : "Decrypt",
(UINT32)CacheFlush,
(UINT32)Mmio
));
//
// Check if we have a valid memory encryption mask
//
AddressEncMask = InternalGetMemEncryptionAddressMask ();
if (!AddressEncMask) {
return RETURN_ACCESS_DENIED;
}
PgTableMask = AddressEncMask | EFI_PAGE_MASK;
if (Length == 0) {
return RETURN_INVALID_PARAMETER;
}
//
// We are going to change the memory encryption attribute from C=0 -> C=1 or
// vice versa Flush the caches to ensure that data is written into memory
// with correct C-bit
//
if (CacheFlush) {
WriteBackInvalidateDataCacheRange ((VOID *)(UINTN)PhysicalAddress, Length);
}
//
// Make sure that the page table is changeable.
//
IsWpEnabled = IsReadOnlyPageWriteProtected ();
if (IsWpEnabled) {
DisableReadOnlyPageWriteProtect ();
}
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 (!Mmio && (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
//
if (Cr3BaseAddress == 0) {
Cr3BaseAddress = AsmReadCr3 ();
}
PageMapLevel4Entry = (VOID *)(Cr3BaseAddress & ~PgTableMask);
PageMapLevel4Entry += PML4_OFFSET (PhysicalAddress);
if (!PageMapLevel4Entry->Bits.Present) {
DEBUG ((
DEBUG_ERROR,
"%a:%a: bad PML4 for Physical=0x%Lx\n",
gEfiCallerBaseName,
__FUNCTION__,
PhysicalAddress
));
Status = RETURN_NO_MAPPING;
goto Done;
}
PageDirectory1GEntry = (VOID *)(
(PageMapLevel4Entry->Bits.PageTableBaseAddress <<
12) & ~PgTableMask
);
PageDirectory1GEntry += PDP_OFFSET (PhysicalAddress);
if (!PageDirectory1GEntry->Bits.Present) {
DEBUG ((
DEBUG_ERROR,
"%a:%a: bad PDPE for Physical=0x%Lx\n",
gEfiCallerBaseName,
__FUNCTION__,
PhysicalAddress
));
Status = RETURN_NO_MAPPING;
goto Done;
}
//
// If the MustBe1 bit is not 1, it's not actually a 1GB entry
//
if (PageDirectory1GEntry->Bits.MustBe1) {
//
// Valid 1GB page
// If we have at least 1GB to go, we can just update this entry
//
if (((PhysicalAddress & (BIT30 - 1)) == 0) && (Length >= BIT30)) {
SetOrClearCBit (&PageDirectory1GEntry->Uint64, Mode);
DEBUG ((
DEBUG_VERBOSE,
"%a:%a: updated 1GB entry for Physical=0x%Lx\n",
gEfiCallerBaseName,
__FUNCTION__,
PhysicalAddress
));
PhysicalAddress += BIT30;
Length -= BIT30;
} else {
//
// We must split the page
//
DEBUG ((
DEBUG_VERBOSE,
"%a:%a: splitting 1GB page for Physical=0x%Lx\n",
gEfiCallerBaseName,
__FUNCTION__,
PhysicalAddress
));
Split1GPageTo2M (
(UINT64)PageDirectory1GEntry->Bits.PageTableBaseAddress << 30,
(UINT64 *)PageDirectory1GEntry,
0,
0
);
continue;
}
} else {
//
// Actually a PDP
//
PageUpperDirectoryPointerEntry =
(PAGE_MAP_AND_DIRECTORY_POINTER *)PageDirectory1GEntry;
PageDirectory2MEntry =
(VOID *)(
(PageUpperDirectoryPointerEntry->Bits.PageTableBaseAddress <<
12) & ~PgTableMask
);
PageDirectory2MEntry += PDE_OFFSET (PhysicalAddress);
if (!PageDirectory2MEntry->Bits.Present) {
DEBUG ((
DEBUG_ERROR,
"%a:%a: bad PDE for Physical=0x%Lx\n",
gEfiCallerBaseName,
__FUNCTION__,
PhysicalAddress
));
Status = RETURN_NO_MAPPING;
goto Done;
}
//
// If the MustBe1 bit is not a 1, it's not a 2MB entry
//
if (PageDirectory2MEntry->Bits.MustBe1) {
//
// Valid 2MB page
// If we have at least 2MB left to go, we can just update this entry
//
if (((PhysicalAddress & (BIT21-1)) == 0) && (Length >= BIT21)) {
SetOrClearCBit (&PageDirectory2MEntry->Uint64, Mode);
PhysicalAddress += BIT21;
Length -= BIT21;
} else {
//
// We must split up this page into 4K pages
//
DEBUG ((
DEBUG_VERBOSE,
"%a:%a: splitting 2MB page for Physical=0x%Lx\n",
gEfiCallerBaseName,
__FUNCTION__,
PhysicalAddress
));
Split2MPageTo4K (
(UINT64)PageDirectory2MEntry->Bits.PageTableBaseAddress << 21,
(UINT64 *)PageDirectory2MEntry,
0,
0
);
continue;
}
} else {
PageDirectoryPointerEntry =
(PAGE_MAP_AND_DIRECTORY_POINTER *)PageDirectory2MEntry;
PageTableEntry =
(VOID *)(
(PageDirectoryPointerEntry->Bits.PageTableBaseAddress <<
12) & ~PgTableMask
);
PageTableEntry += PTE_OFFSET (PhysicalAddress);
if (!PageTableEntry->Bits.Present) {
DEBUG ((
DEBUG_ERROR,
"%a:%a: bad PTE for Physical=0x%Lx\n",
gEfiCallerBaseName,
__FUNCTION__,
PhysicalAddress
));
Status = RETURN_NO_MAPPING;
goto Done;
}
SetOrClearCBit (&PageTableEntry->Uint64, Mode);
PhysicalAddress += EFI_PAGE_SIZE;
Length -= EFI_PAGE_SIZE;
}
}
}
//
// Protect the page table by marking the memory used for page table to be
// read-only.
//
if (IsWpEnabled) {
EnablePageTableProtection ((UINTN)PageMapLevel4Entry, TRUE);
}
//
// Flush TLB
//
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.
//
if (IsWpEnabled) {
EnableReadOnlyPageWriteProtect ();
}
return Status;
}
/**
This function clears memory encryption bit for the memory region specified by
PhysicalAddress and Length from the current page table context.
@param[in] Cr3BaseAddress Cr3 Base Address (if zero then use
current CR3)
@param[in] PhysicalAddress The physical address that is the start
address of a memory region.
@param[in] Length The length of memory region
@retval RETURN_SUCCESS The attributes were cleared for the
memory region.
@retval RETURN_INVALID_PARAMETER Number of pages is zero.
@retval RETURN_UNSUPPORTED Clearing the memory encyrption attribute
is not supported
**/
RETURN_STATUS
EFIAPI
InternalMemEncryptSevSetMemoryDecrypted (
IN PHYSICAL_ADDRESS Cr3BaseAddress,
IN PHYSICAL_ADDRESS PhysicalAddress,
IN UINTN Length
)
{
return SetMemoryEncDec (
Cr3BaseAddress,
PhysicalAddress,
Length,
ClearCBit,
TRUE,
FALSE
);
}
/**
This function sets memory encryption bit for the memory region specified by
PhysicalAddress and Length from the current page table context.
@param[in] Cr3BaseAddress Cr3 Base Address (if zero then use
current CR3)
@param[in] PhysicalAddress The physical address that is the start
address of a memory region.
@param[in] Length The length of memory region
@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 encyrption attribute
is not supported
**/
RETURN_STATUS
EFIAPI
InternalMemEncryptSevSetMemoryEncrypted (
IN PHYSICAL_ADDRESS Cr3BaseAddress,
IN PHYSICAL_ADDRESS PhysicalAddress,
IN UINTN Length
)
{
return SetMemoryEncDec (
Cr3BaseAddress,
PhysicalAddress,
Length,
SetCBit,
TRUE,
FALSE
);
}
/**
This function clears memory encryption bit for the MMIO region specified by
PhysicalAddress and Length.
@param[in] Cr3BaseAddress Cr3 Base Address (if zero then use
current CR3)
@param[in] PhysicalAddress The physical address that is the start
address of a MMIO region.
@param[in] Length The length of memory region
@retval RETURN_SUCCESS The attributes were cleared for the
memory region.
@retval RETURN_INVALID_PARAMETER Length is zero.
@retval RETURN_UNSUPPORTED Clearing the memory encyrption attribute
is not supported
**/
RETURN_STATUS
EFIAPI
InternalMemEncryptSevClearMmioPageEncMask (
IN PHYSICAL_ADDRESS Cr3BaseAddress,
IN PHYSICAL_ADDRESS PhysicalAddress,
IN UINTN Length
)
{
return SetMemoryEncDec (
Cr3BaseAddress,
PhysicalAddress,
Length,
ClearCBit,
FALSE,
TRUE
);
}
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