;------------------------------------------------------------------------------
|
; @file
|
; Sets the CR3 register for 64-bit paging
|
;
|
; Copyright (c) 2008 - 2013, Intel Corporation. All rights reserved.<BR>
|
; Copyright (c) 2017 - 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
|
; SPDX-License-Identifier: BSD-2-Clause-Patent
|
;
|
;------------------------------------------------------------------------------
|
|
BITS 32
|
|
%define PAGE_PRESENT 0x01
|
%define PAGE_READ_WRITE 0x02
|
%define PAGE_USER_SUPERVISOR 0x04
|
%define PAGE_WRITE_THROUGH 0x08
|
%define PAGE_CACHE_DISABLE 0x010
|
%define PAGE_ACCESSED 0x020
|
%define PAGE_DIRTY 0x040
|
%define PAGE_PAT 0x080
|
%define PAGE_GLOBAL 0x0100
|
%define PAGE_2M_MBO 0x080
|
%define PAGE_2M_PAT 0x01000
|
|
%define PAGE_4K_PDE_ATTR (PAGE_ACCESSED + \
|
PAGE_DIRTY + \
|
PAGE_READ_WRITE + \
|
PAGE_PRESENT)
|
|
%define PAGE_2M_PDE_ATTR (PAGE_2M_MBO + \
|
PAGE_ACCESSED + \
|
PAGE_DIRTY + \
|
PAGE_READ_WRITE + \
|
PAGE_PRESENT)
|
|
%define PAGE_PDP_ATTR (PAGE_ACCESSED + \
|
PAGE_READ_WRITE + \
|
PAGE_PRESENT)
|
|
;
|
; Modified: EAX, EBX, ECX, EDX
|
;
|
SetCr3ForPageTables64:
|
|
; Clear the WorkArea header. The SEV probe routines will populate the
|
; work area when detected.
|
mov byte[WORK_AREA_GUEST_TYPE], 0
|
|
; Check whether the SEV is active and populate the SevEsWorkArea
|
OneTimeCall CheckSevFeatures
|
|
; If SEV is enabled, the C-bit position is always above 31.
|
; The mask will be saved in the EDX and applied during the
|
; the page table build below.
|
OneTimeCall GetSevCBitMaskAbove31
|
|
;
|
; For OVMF, build some initial page tables at
|
; PcdOvmfSecPageTablesBase - (PcdOvmfSecPageTablesBase + 0x6000).
|
;
|
; This range should match with PcdOvmfSecPageTablesSize which is
|
; declared in the FDF files.
|
;
|
; At the end of PEI, the pages tables will be rebuilt into a
|
; more permanent location by DxeIpl.
|
;
|
|
mov ecx, 6 * 0x1000 / 4
|
xor eax, eax
|
clearPageTablesMemoryLoop:
|
mov dword[ecx * 4 + PT_ADDR (0) - 4], eax
|
loop clearPageTablesMemoryLoop
|
|
;
|
; Top level Page Directory Pointers (1 * 512GB entry)
|
;
|
mov dword[PT_ADDR (0)], PT_ADDR (0x1000) + PAGE_PDP_ATTR
|
mov dword[PT_ADDR (4)], edx
|
|
;
|
; Next level Page Directory Pointers (4 * 1GB entries => 4GB)
|
;
|
mov dword[PT_ADDR (0x1000)], PT_ADDR (0x2000) + PAGE_PDP_ATTR
|
mov dword[PT_ADDR (0x1004)], edx
|
mov dword[PT_ADDR (0x1008)], PT_ADDR (0x3000) + PAGE_PDP_ATTR
|
mov dword[PT_ADDR (0x100C)], edx
|
mov dword[PT_ADDR (0x1010)], PT_ADDR (0x4000) + PAGE_PDP_ATTR
|
mov dword[PT_ADDR (0x1014)], edx
|
mov dword[PT_ADDR (0x1018)], PT_ADDR (0x5000) + PAGE_PDP_ATTR
|
mov dword[PT_ADDR (0x101C)], edx
|
|
;
|
; Page Table Entries (2048 * 2MB entries => 4GB)
|
;
|
mov ecx, 0x800
|
pageTableEntriesLoop:
|
mov eax, ecx
|
dec eax
|
shl eax, 21
|
add eax, PAGE_2M_PDE_ATTR
|
mov [ecx * 8 + PT_ADDR (0x2000 - 8)], eax
|
mov [(ecx * 8 + PT_ADDR (0x2000 - 8)) + 4], edx
|
loop pageTableEntriesLoop
|
|
; Clear the C-bit from the GHCB page if the SEV-ES is enabled.
|
OneTimeCall SevClearPageEncMaskForGhcbPage
|
|
SetCr3:
|
;
|
; Set CR3 now that the paging structures are available
|
;
|
mov eax, PT_ADDR (0)
|
mov cr3, eax
|
|
OneTimeCallRet SetCr3ForPageTables64
|
