From 6cf57789614b591da97862acf98dfc7c31a52bf1 Mon Sep 17 00:00:00 2001 From: Jordan Justen Date: Thu, 18 Jul 2013 22:51:27 +0000 Subject: [PATCH] OvmfPkg/Sec: Build identity mapped pages in RAM for X64 This is based on MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c. Previously we would run using page tables built into the firmware device. If a flash memory is available, it is unsafe for the page tables to be stored in memory since the processor may try to write to the page table data structures. Additionally, when KVM ROM support is enabled for the firmware device, then PEI fails to boot when the page tables are in the firmware device. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Jordan Justen Reviewed-by: Laszlo Ersek git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14494 6f19259b-4bc3-4df7-8a09-765794883524 --- OvmfPkg/Sec/SecMain.c | 144 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 142 insertions(+), 2 deletions(-) diff --git a/OvmfPkg/Sec/SecMain.c b/OvmfPkg/Sec/SecMain.c index 3882dadd63..56081c9b44 100644 --- a/OvmfPkg/Sec/SecMain.c +++ b/OvmfPkg/Sec/SecMain.c @@ -1,7 +1,7 @@ /** @file Main SEC phase code. Transitions to PEI. - Copyright (c) 2008 - 2011, Intel Corporation. All rights reserved.
+ Copyright (c) 2008 - 2013, Intel Corporation. All rights reserved.
This program and the accompanying materials are licensed and made available under the terms and conditions of the BSD License @@ -31,6 +31,8 @@ #include +#include + #define SEC_IDT_ENTRY_COUNT 34 typedef struct _SEC_IDT_TABLE { @@ -523,6 +525,137 @@ FindImageBase ( } } +#if defined (MDE_CPU_X64) +/** + Allocates and fills in the Page Directory and Page Table Entries to + establish a 1:1 Virtual to Physical mapping. + + @param Location Memory to build the page tables in + +**/ +VOID +Create4GbIdentityMappingPageTables ( + VOID *Location + ) +{ + UINT32 RegEax; + UINT32 RegEdx; + EFI_PHYSICAL_ADDRESS PageAddress; + UINTN IndexOfPml4Entries; + UINTN IndexOfPdpEntries; + UINTN IndexOfPageDirectoryEntries; + UINT32 NumberOfPml4EntriesNeeded; + UINT32 NumberOfPdpEntriesNeeded; + X64_PAGE_MAP_AND_DIRECTORY_POINTER *PageMapLevel4Entry; + X64_PAGE_MAP_AND_DIRECTORY_POINTER *PageMap; + X64_PAGE_MAP_AND_DIRECTORY_POINTER *PageDirectoryPointerEntry; + X64_PAGE_TABLE_ENTRY *PageDirectoryEntry; + UINTN NextAllocAddress; + BOOLEAN Page1GSupport; + X64_PAGE_TABLE_1G_ENTRY *PageDirectory1GEntry; + + Page1GSupport = FALSE; + AsmCpuid (0x80000000, &RegEax, NULL, NULL, NULL); + if (RegEax >= 0x80000001) { + AsmCpuid (0x80000001, NULL, NULL, NULL, &RegEdx); + if ((RegEdx & BIT26) != 0) { + Page1GSupport = TRUE; + } + } + + // + // Only build entries for the first 4GB at this stage. + // + NumberOfPml4EntriesNeeded = 1; + NumberOfPdpEntriesNeeded = 4; + + NextAllocAddress = (UINTN) Location; + + // + // By architecture only one PageMapLevel4 exists - so lets allocate storage for it. + // + PageMap = (VOID *) NextAllocAddress; + NextAllocAddress += SIZE_4KB; + + PageMapLevel4Entry = PageMap; + PageAddress = 0; + for (IndexOfPml4Entries = 0; IndexOfPml4Entries < NumberOfPml4EntriesNeeded; IndexOfPml4Entries++, PageMapLevel4Entry++) { + // + // Each PML4 entry points to a page of Page Directory Pointer entires. + // So lets allocate space for them and fill them in in the IndexOfPdpEntries loop. + // + PageDirectoryPointerEntry = (VOID *) NextAllocAddress; + NextAllocAddress += SIZE_4KB; + + // + // Make a PML4 Entry + // + PageMapLevel4Entry->Uint64 = (UINT64)(UINTN)PageDirectoryPointerEntry; + PageMapLevel4Entry->Bits.ReadWrite = 1; + PageMapLevel4Entry->Bits.Present = 1; + + if (Page1GSupport) { + PageDirectory1GEntry = (VOID *) PageDirectoryPointerEntry; + + for (IndexOfPageDirectoryEntries = 0; IndexOfPageDirectoryEntries < 512; IndexOfPageDirectoryEntries++, PageDirectory1GEntry++, PageAddress += SIZE_1GB) { + // + // Fill in the Page Directory entries + // + PageDirectory1GEntry->Uint64 = (UINT64)PageAddress; + PageDirectory1GEntry->Bits.ReadWrite = 1; + PageDirectory1GEntry->Bits.Present = 1; + PageDirectory1GEntry->Bits.MustBe1 = 1; + } + } else { + for (IndexOfPdpEntries = 0; IndexOfPdpEntries < NumberOfPdpEntriesNeeded; IndexOfPdpEntries++, PageDirectoryPointerEntry++) { + // + // Each Directory Pointer entries points to a page of Page Directory entires. + // So allocate space for them and fill them in in the IndexOfPageDirectoryEntries loop. + // + PageDirectoryEntry = (VOID *) NextAllocAddress; + NextAllocAddress += SIZE_4KB; + + // + // Fill in a Page Directory Pointer Entries + // + PageDirectoryPointerEntry->Uint64 = (UINT64)(UINTN)PageDirectoryEntry; + PageDirectoryPointerEntry->Bits.ReadWrite = 1; + PageDirectoryPointerEntry->Bits.Present = 1; + + for (IndexOfPageDirectoryEntries = 0; IndexOfPageDirectoryEntries < 512; IndexOfPageDirectoryEntries++, PageDirectoryEntry++, PageAddress += SIZE_2MB) { + // + // Fill in the Page Directory entries + // + PageDirectoryEntry->Uint64 = (UINT64)PageAddress; + PageDirectoryEntry->Bits.ReadWrite = 1; + PageDirectoryEntry->Bits.Present = 1; + PageDirectoryEntry->Bits.MustBe1 = 1; + } + } + + for (; IndexOfPdpEntries < 512; IndexOfPdpEntries++, PageDirectoryPointerEntry++) { + ZeroMem ( + PageDirectoryPointerEntry, + sizeof(X64_PAGE_MAP_AND_DIRECTORY_POINTER) + ); + } + } + } + + // + // For the PML4 entries we are not using fill in a null entry. + // + for (; IndexOfPml4Entries < 512; IndexOfPml4Entries++, PageMapLevel4Entry++) { + ZeroMem ( + PageMapLevel4Entry, + sizeof (X64_PAGE_MAP_AND_DIRECTORY_POINTER) + ); + } + + AsmWriteCr3 ((UINTN) PageMap); +} +#endif + /* Find and return Pei Core entry point. @@ -645,7 +778,14 @@ SecCoreStartupWithStack ( // IoWrite8 (0x21, 0xff); IoWrite8 (0xA1, 0xff); - + +#if defined (MDE_CPU_X64) + // + // Create Identity Mapped Pages in RAM + // + Create4GbIdentityMappingPageTables (TopOfCurrentStack); +#endif + // // Initialize Debug Agent to support source level debug in SEC/PEI phases before memory ready. // -- 2.39.2