Merged https://github.com/tianocore/edk2/pull/3420
> -----Original Message-----
> From: Yao, Jiewen
> Sent: Tuesday, September 27, 2022 4:22 PM
> To: Xu, Min M <min.m...@intel.com>; devel@edk2.groups.io
> Cc: Aktas, Erdem <erdemak...@google.com>; Gerd Hoffmann
> <kra...@redhat.com>; James Bottomley <j...@linux.ibm.com>
> Subject: RE: [PATCH V2 1/1] OvmfPkg/PeilessStartupLib: move
> mPageTablePool to stack
>
> Reviewed-by: Jiewen Yao <jiewen....@intel.com>
>
> > -----Original Message-----
> > From: Xu, Min M <min.m...@intel.com>
> > Sent: Tuesday, September 27, 2022 3:08 PM
> > To: devel@edk2.groups.io
> > Cc: Xu, Min M <min.m...@intel.com>; Aktas, Erdem
> > <erdemak...@google.com>; Gerd Hoffmann <kra...@redhat.com>;
> James
> > Bottomley <j...@linux.ibm.com>; Yao, Jiewen <jiewen....@intel.com>
> > Subject: [PATCH V2 1/1] OvmfPkg/PeilessStartupLib: move
> mPageTablePool
> > to stack
> >
> > From: Min M Xu <min.m...@intel.com>
> >
> > PeilessStartupLib is running in SEC phase. In this phase global variable
> > is not allowed to be modified. This patch moves mPageTablePool to stack
> > and pass it as input parameter between functions.
> >
> > Cc: Erdem Aktas <erdemak...@google.com>
> > Cc: Gerd Hoffmann <kra...@redhat.com>
> > Cc: James Bottomley <j...@linux.ibm.com>
> > Cc: Jiewen Yao <jiewen....@intel.com>
> > Signed-off-by: Min Xu <min.m...@intel.com>
> > ---
> > .../PeilessStartupLib/X64/VirtualMemory.c | 117 ++++++++++--------
> > 1 file changed, 68 insertions(+), 49 deletions(-)
> >
> > diff --git a/OvmfPkg/Library/PeilessStartupLib/X64/VirtualMemory.c
> > b/OvmfPkg/Library/PeilessStartupLib/X64/VirtualMemory.c
> > index 6877e521e485..b444c052d1bf 100644
> > --- a/OvmfPkg/Library/PeilessStartupLib/X64/VirtualMemory.c
> > +++ b/OvmfPkg/Library/PeilessStartupLib/X64/VirtualMemory.c
> > @@ -21,11 +21,6 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
> > #include <Library/PlatformInitLib.h>
> > #include "PageTables.h"
> >
> > -//
> > -// Global variable to keep track current available memory used as page
> > table.
> > -//
> > -PAGE_TABLE_POOL *mPageTablePool = NULL;
> > -
> > UINTN mLevelShift[5] = {
> > 0,
> > PAGING_L1_ADDRESS_SHIFT,
> > @@ -273,14 +268,17 @@ ToSplitPageTable (
> > reserve at least another PAGE_TABLE_POOL_UNIT_PAGES. But usually
> > this won't
> > happen in practice.
> >
> > - @param PoolPages The least page number of the pool to be created.
> > + @param[in] PoolPages The least page number of the pool to be
> > created.
> > + @param[in, out] PageTablePool Pointer of Pointer to the current
> > available memory
> > + used as page table.
> >
> > @retval TRUE The pool is initialized successfully.
> > @retval FALSE The memory is out of resource.
> > **/
> > BOOLEAN
> > InitializePageTablePool (
> > - IN UINTN PoolPages
> > + IN UINTN PoolPages,
> > + IN OUT PAGE_TABLE_POOL **PageTablePool
> > )
> > {
> > VOID *Buffer;
> > @@ -303,20 +301,20 @@ InitializePageTablePool (
> > //
> > // Link all pools into a list for easier track later.
> > //
> > - if (mPageTablePool == NULL) {
> > - mPageTablePool = Buffer;
> > - mPageTablePool->NextPool = mPageTablePool;
> > + if (*PageTablePool == NULL) {
> > + *(UINT64 *)(UINTN)PageTablePool = (UINT64)(UINTN)Buffer;
> > + (*PageTablePool)->NextPool = *PageTablePool;
> > } else {
> > - ((PAGE_TABLE_POOL *)Buffer)->NextPool = mPageTablePool-
> >NextPool;
> > - mPageTablePool->NextPool = Buffer;
> > - mPageTablePool = Buffer;
> > + ((PAGE_TABLE_POOL *)Buffer)->NextPool = (*PageTablePool)-
> >NextPool;
> > + (*PageTablePool)->NextPool = Buffer;
> > + *PageTablePool = Buffer;
> > }
> >
> > //
> > // Reserve one page for pool header.
> > //
> > - mPageTablePool->FreePages = PoolPages - 1;
> > - mPageTablePool->Offset = EFI_PAGES_TO_SIZE (1);
> > + (*PageTablePool)->FreePages = PoolPages - 1;
> > + (*PageTablePool)->Offset = EFI_PAGES_TO_SIZE (1);
> >
> > return TRUE;
> > }
> > @@ -333,14 +331,17 @@ InitializePageTablePool (
> > 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.
> > + @param[in] Pages The number of 4 KB pages to
> > allocate.
> > + @param[in, out] PageTablePool Pointer of pointer to the current
> > available
> > + memory used as page table.
> >
> > @return A pointer to the allocated buffer or NULL if allocation fails.
> >
> > **/
> > VOID *
> > AllocatePageTableMemory (
> > - IN UINTN Pages
> > + IN UINTN Pages,
> > + IN OUT PAGE_TABLE_POOL **PageTablePool
> > )
> > {
> > VOID *Buffer;
> > @@ -349,30 +350,31 @@ AllocatePageTableMemory (
> > return NULL;
> > }
> >
> > - DEBUG ((DEBUG_INFO, "AllocatePageTableMemory.
> mPageTablePool=%p,
> > Pages=%d\n", mPageTablePool, Pages));
> > + DEBUG ((DEBUG_INFO, "AllocatePageTableMemory. PageTablePool=%p,
> > Pages=%d\n", *PageTablePool, Pages));
> > //
> > // Renew the pool if necessary.
> > //
> > - if ((mPageTablePool == NULL) ||
> > - (Pages > mPageTablePool->FreePages))
> > + if ((*PageTablePool == NULL) ||
> > + (Pages > (*PageTablePool)->FreePages))
> > {
> > - if (!InitializePageTablePool (Pages)) {
> > + if (!InitializePageTablePool (Pages, PageTablePool)) {
> > return NULL;
> > }
> > }
> >
> > - Buffer = (UINT8 *)mPageTablePool + mPageTablePool->Offset;
> > + Buffer = (UINT8 *)(*PageTablePool) + (*PageTablePool)->Offset;
> >
> > - mPageTablePool->Offset += EFI_PAGES_TO_SIZE (Pages);
> > - mPageTablePool->FreePages -= Pages;
> > + (*PageTablePool)->Offset += EFI_PAGES_TO_SIZE (Pages);
> > + (*PageTablePool)->FreePages -= Pages;
> >
> > DEBUG ((
> > DEBUG_INFO,
> > - "%a:%a: Buffer=0x%Lx Pages=%ld\n",
> > + "%a:%a: Buffer=0x%Lx Pages=%ld, PageTablePool=%p\n",
> > gEfiCallerBaseName,
> > __FUNCTION__,
> > Buffer,
> > - Pages
> > + Pages,
> > + *PageTablePool
> > ));
> >
> > return Buffer;
> > @@ -385,6 +387,8 @@ AllocatePageTableMemory (
> > @param[in, out] PageEntry2M Pointer to 2M page entry.
> > @param[in] StackBase Stack base address.
> > @param[in] StackSize Stack size.
> > + @param[in, out] PageTablePool Pointer to the current available
> > memory used as
> > + page table.
> >
> > **/
> > VOID
> > @@ -392,7 +396,8 @@ Split2MPageTo4K (
> > IN EFI_PHYSICAL_ADDRESS PhysicalAddress,
> > IN OUT UINT64 *PageEntry2M,
> > IN EFI_PHYSICAL_ADDRESS StackBase,
> > - IN UINTN StackSize
> > + IN UINTN StackSize,
> > + IN OUT PAGE_TABLE_POOL *PageTablePool
> > )
> > {
> > EFI_PHYSICAL_ADDRESS PhysicalAddress4K;
> > @@ -401,7 +406,7 @@ Split2MPageTo4K (
> >
> > DEBUG ((DEBUG_INFO, "Split2MPageTo4K\n"));
> >
> > - PageTableEntry = AllocatePageTableMemory (1);
> > + PageTableEntry = AllocatePageTableMemory (1, &PageTablePool);
> >
> > if (PageTableEntry == NULL) {
> > ASSERT (FALSE);
> > @@ -448,6 +453,8 @@ Split2MPageTo4K (
> > @param[in, out] PageEntry1G Pointer to 1G page entry.
> > @param[in] StackBase Stack base address.
> > @param[in] StackSize Stack size.
> > + @param[in, out] PageTablePool Pointer to the current available
> > memory used as
> > + page table.
> >
> > **/
> > VOID
> > @@ -455,14 +462,16 @@ Split1GPageTo2M (
> > IN EFI_PHYSICAL_ADDRESS PhysicalAddress,
> > IN OUT UINT64 *PageEntry1G,
> > IN EFI_PHYSICAL_ADDRESS StackBase,
> > - IN UINTN StackSize
> > + IN UINTN StackSize,
> > + IN OUT PAGE_TABLE_POOL *PageTablePool
> > )
> > {
> > EFI_PHYSICAL_ADDRESS PhysicalAddress2M;
> > UINTN IndexOfPageDirectoryEntries;
> > PAGE_TABLE_ENTRY *PageDirectoryEntry;
> >
> > - PageDirectoryEntry = AllocatePageTableMemory (1);
> > + DEBUG ((DEBUG_INFO, "Split1GPageTo2M\n"));
> > + PageDirectoryEntry = AllocatePageTableMemory (1, &PageTablePool);
> >
> > if (PageDirectoryEntry == NULL) {
> > ASSERT (FALSE);
> > @@ -480,7 +489,7 @@ Split1GPageTo2M (
> > //
> > // Need to split this 2M page that covers NULL or stack range.
> > //
> > - Split2MPageTo4K (PhysicalAddress2M, (UINT64 *)PageDirectoryEntry,
> > StackBase, StackSize);
> > + Split2MPageTo4K (PhysicalAddress2M, (UINT64
> *)PageDirectoryEntry,
> > StackBase, StackSize, PageTablePool);
> > } else {
> > //
> > // Fill in the Page Directory entries
> > @@ -496,16 +505,19 @@ Split1GPageTo2M (
> > /**
> > 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.
> > + @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.
> > + @param[in, out] PageTablePool Pointer to the current available
> > memory used as
> > + page table.
> >
> > **/
> > VOID
> > SetPageTablePoolReadOnly (
> > IN UINTN PageTableBase,
> > IN EFI_PHYSICAL_ADDRESS Address,
> > - IN BOOLEAN Level4Paging
> > + IN BOOLEAN Level4Paging,
> > + IN OUT PAGE_TABLE_POOL *PageTablePool
> > )
> > {
> > UINTN Index;
> > @@ -573,7 +585,8 @@ SetPageTablePoolReadOnly (
> > //
> > ASSERT (Level > 1);
> >
> > - NewPageTable = AllocatePageTableMemory (1);
> > + DEBUG ((DEBUG_INFO, "SetPageTablePoolReadOnly\n"));
> > + NewPageTable = AllocatePageTableMemory (1, &PageTablePool);
> >
> > if (NewPageTable == NULL) {
> > ASSERT (FALSE);
> > @@ -604,14 +617,17 @@ SetPageTablePoolReadOnly (
> > /**
> > 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.
> > + @param[in] PageTableBase Base address of page table (CR3).
> > + @param[in] Level4Paging Level 4 paging flag.
> > + @param[in, out] PageTablePool Pointer to the current available
> > memory used as
> > + page table.
> >
> > **/
> > VOID
> > EnablePageTableProtection (
> > - IN UINTN PageTableBase,
> > - IN BOOLEAN Level4Paging
> > + IN UINTN PageTableBase,
> > + IN BOOLEAN Level4Paging,
> > + IN OUT PAGE_TABLE_POOL *PageTablePool
> > )
> > {
> > PAGE_TABLE_POOL *HeadPool;
> > @@ -621,7 +637,7 @@ EnablePageTableProtection (
> >
> > DEBUG ((DEBUG_INFO, "EnablePageTableProtection\n"));
> >
> > - if (mPageTablePool == NULL) {
> > + if (PageTablePool == NULL) {
> > return;
> > }
> >
> > @@ -632,10 +648,10 @@ EnablePageTableProtection (
> > AsmWriteCr0 (AsmReadCr0 () & ~CR0_WP);
> >
> > //
> > - // SetPageTablePoolReadOnly might update mPageTablePool. It's safer
> to
> > + // SetPageTablePoolReadOnly might update PageTablePool. It's safer to
> > // remember original one in advance.
> > //
> > - HeadPool = mPageTablePool;
> > + HeadPool = PageTablePool;
> > Pool = HeadPool;
> > do {
> > Address = (EFI_PHYSICAL_ADDRESS)(UINTN)Pool;
> > @@ -647,7 +663,7 @@ EnablePageTableProtection (
> > // protection to them one by one.
> > //
> > while (PoolSize > 0) {
> > - SetPageTablePoolReadOnly (PageTableBase, Address, Level4Paging);
> > + SetPageTablePoolReadOnly (PageTableBase, Address, Level4Paging,
> > PageTablePool);
> > Address += PAGE_TABLE_POOL_UNIT_SIZE;
> > PoolSize -= PAGE_TABLE_POOL_UNIT_SIZE;
> > }
> > @@ -700,6 +716,7 @@ CreateIdentityMappingPageTables (
> > BOOLEAN Page1GSupport;
> > PAGE_TABLE_1G_ENTRY *PageDirectory1GEntry;
> > IA32_CR4 Cr4;
> > + PAGE_TABLE_POOL *PageTablePool;
> >
> > //
> > // Set PageMapLevel5Entry to suppress incorrect compiler/analyzer
> > warnings
> > @@ -785,13 +802,14 @@ CreateIdentityMappingPageTables (
> > (UINT64)TotalPagesNum
> > ));
> >
> > - BigPageAddress = (UINTN)AllocatePageTableMemory (TotalPagesNum);
> > + PageTablePool = NULL;
> > + BigPageAddress = (UINTN)AllocatePageTableMemory (TotalPagesNum,
> > &PageTablePool);
> > if (BigPageAddress == 0) {
> > ASSERT (FALSE);
> > return 0;
> > }
> >
> > - DEBUG ((DEBUG_INFO, "BigPageAddress = 0x%llx\n", BigPageAddress));
> > + DEBUG ((DEBUG_INFO, "BigPageAddress = 0x%llx,
> PageTablePool=%p\n",
> > BigPageAddress, PageTablePool));
> >
> > //
> > // By architecture only one PageMapLevel4 exists - so lets allocate
> storage
> > for it.
> > @@ -856,7 +874,8 @@ CreateIdentityMappingPageTables (
> > PageAddress,
> > (UINT64 *)PageDirectory1GEntry,
> > StackBase,
> > - StackSize
> > + StackSize,
> > + PageTablePool
> > );
> > } else {
> > //
> > @@ -892,7 +911,7 @@ CreateIdentityMappingPageTables (
> > //
> > // Need to split this 2M page that covers NULL or stack
> > range.
> > //
> > - Split2MPageTo4K (PageAddress, (UINT64 *)PageDirectoryEntry,
> > StackBase, StackSize);
> > + Split2MPageTo4K (PageAddress, (UINT64 *)PageDirectoryEntry,
> > StackBase, StackSize, PageTablePool);
> > } else {
> > //
> > // Fill in the Page Directory entries
> > @@ -929,7 +948,7 @@ CreateIdentityMappingPageTables (
> > // Protect the page table by marking the memory used for page table to
> > be
> > // read-only.
> > //
> > - EnablePageTableProtection ((UINTN)PageMap, TRUE);
> > + EnablePageTableProtection ((UINTN)PageMap, TRUE, PageTablePool);
> >
> > return (UINTN)PageMap;
> > }
> > --
> > 2.29.2.windows.2
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