mirror of https://github.com/acidanthera/audk.git
OvmfPkg/ResetVector: move SEV specific code in a separate file
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275 The PageTables64.asm was created to provide routines to set the CR3 register for 64-bit paging. During the SEV support, it grew to include a lot of the SEV stuff. Before adding more SEV features, let's move all the SEV-specific routines into a separate file. No functionality change intended. 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: Laszlo Ersek <lersek@redhat.com> Cc: Erdem Aktas <erdemaktas@google.com> Reviewed-by: Jiewen Yao <jiewen.yao@intel.com> Acked-by: Ard Biesheuvel <ardb+tianocore@kernel.org> Suggested-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
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b461d67639
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@ -0,0 +1,400 @@
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;------------------------------------------------------------------------------
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; @file
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; Provide the functions to check whether SEV and SEV-ES is enabled.
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;
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; Copyright (c) 2017 - 2021, Advanced Micro Devices, Inc. All rights reserved.<BR>
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; SPDX-License-Identifier: BSD-2-Clause-Patent
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;
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;------------------------------------------------------------------------------
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BITS 32
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;
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; SEV-ES #VC exception handler support
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;
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; #VC handler local variable locations
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;
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%define VC_CPUID_RESULT_EAX 0
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%define VC_CPUID_RESULT_EBX 4
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%define VC_CPUID_RESULT_ECX 8
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%define VC_CPUID_RESULT_EDX 12
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%define VC_GHCB_MSR_EDX 16
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%define VC_GHCB_MSR_EAX 20
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%define VC_CPUID_REQUEST_REGISTER 24
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%define VC_CPUID_FUNCTION 28
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; #VC handler total local variable size
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;
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%define VC_VARIABLE_SIZE 32
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; #VC handler GHCB CPUID request/response protocol values
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;
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%define GHCB_CPUID_REQUEST 4
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%define GHCB_CPUID_RESPONSE 5
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%define GHCB_CPUID_REGISTER_SHIFT 30
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%define CPUID_INSN_LEN 2
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; Check if Secure Encrypted Virtualization (SEV) features are enabled.
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;
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; Register usage is tight in this routine, so multiple calls for the
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; same CPUID and MSR data are performed to keep things simple.
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;
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; Modified: EAX, EBX, ECX, EDX, ESP
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;
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; If SEV is enabled then EAX will be at least 32.
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; If SEV is disabled then EAX will be zero.
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;
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CheckSevFeatures:
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; Set the first byte of the workarea to zero to communicate to the SEC
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; phase that SEV-ES is not enabled. If SEV-ES is enabled, the CPUID
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; instruction will trigger a #VC exception where the first byte of the
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; workarea will be set to one or, if CPUID is not being intercepted,
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; the MSR check below will set the first byte of the workarea to one.
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mov byte[SEV_ES_WORK_AREA], 0
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;
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; Set up exception handlers to check for SEV-ES
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; Load temporary RAM stack based on PCDs (see SevEsIdtVmmComm for
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; stack usage)
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; Establish exception handlers
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;
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mov esp, SEV_ES_VC_TOP_OF_STACK
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mov eax, ADDR_OF(Idtr)
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lidt [cs:eax]
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; Check if we have a valid (0x8000_001F) CPUID leaf
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; CPUID raises a #VC exception if running as an SEV-ES guest
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mov eax, 0x80000000
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cpuid
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; This check should fail on Intel or Non SEV AMD CPUs. In future if
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; Intel CPUs supports this CPUID leaf then we are guranteed to have exact
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; same bit definition.
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cmp eax, 0x8000001f
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jl NoSev
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; Check for SEV memory encryption feature:
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; CPUID Fn8000_001F[EAX] - Bit 1
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; CPUID raises a #VC exception if running as an SEV-ES guest
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mov eax, 0x8000001f
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cpuid
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bt eax, 1
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jnc NoSev
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; Check if SEV memory encryption is enabled
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; MSR_0xC0010131 - Bit 0 (SEV enabled)
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mov ecx, 0xc0010131
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rdmsr
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bt eax, 0
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jnc NoSev
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; Check for SEV-ES memory encryption feature:
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; CPUID Fn8000_001F[EAX] - Bit 3
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; CPUID raises a #VC exception if running as an SEV-ES guest
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mov eax, 0x8000001f
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cpuid
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bt eax, 3
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jnc GetSevEncBit
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; Check if SEV-ES is enabled
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; MSR_0xC0010131 - Bit 1 (SEV-ES enabled)
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mov ecx, 0xc0010131
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rdmsr
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bt eax, 1
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jnc GetSevEncBit
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; Set the first byte of the workarea to one to communicate to the SEC
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; phase that SEV-ES is enabled.
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mov byte[SEV_ES_WORK_AREA], 1
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GetSevEncBit:
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; Get pte bit position to enable memory encryption
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; CPUID Fn8000_001F[EBX] - Bits 5:0
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;
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and ebx, 0x3f
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mov eax, ebx
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; The encryption bit position is always above 31
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sub ebx, 32
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jns SevSaveMask
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; Encryption bit was reported as 31 or below, enter a HLT loop
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SevEncBitLowHlt:
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cli
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hlt
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jmp SevEncBitLowHlt
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SevSaveMask:
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xor edx, edx
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bts edx, ebx
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mov dword[SEV_ES_WORK_AREA_ENC_MASK], 0
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mov dword[SEV_ES_WORK_AREA_ENC_MASK + 4], edx
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jmp SevExit
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NoSev:
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;
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; Perform an SEV-ES sanity check by seeing if a #VC exception occurred.
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;
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cmp byte[SEV_ES_WORK_AREA], 0
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jz NoSevPass
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;
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; A #VC was received, yet CPUID indicates no SEV-ES support, something
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; isn't right.
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;
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NoSevEsVcHlt:
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cli
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hlt
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jmp NoSevEsVcHlt
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NoSevPass:
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xor eax, eax
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SevExit:
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;
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; Clear exception handlers and stack
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;
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push eax
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mov eax, ADDR_OF(IdtrClear)
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lidt [cs:eax]
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pop eax
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mov esp, 0
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OneTimeCallRet CheckSevFeatures
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; Check if Secure Encrypted Virtualization - Encrypted State (SEV-ES) feature
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; is enabled.
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;
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; Modified: EAX
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;
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; If SEV-ES is enabled then EAX will be non-zero.
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; If SEV-ES is disabled then EAX will be zero.
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;
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IsSevEsEnabled:
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xor eax, eax
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; During CheckSevFeatures, the SEV_ES_WORK_AREA was set to 1 if
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; SEV-ES is enabled.
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cmp byte[SEV_ES_WORK_AREA], 1
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jne SevEsDisabled
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mov eax, 1
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SevEsDisabled:
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OneTimeCallRet IsSevEsEnabled
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; Start of #VC exception handling routines
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;
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SevEsIdtNotCpuid:
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;
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; Use VMGEXIT to request termination.
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; 1 - #VC was not for CPUID
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;
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mov eax, 1
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jmp SevEsIdtTerminate
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SevEsIdtNoCpuidResponse:
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;
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; Use VMGEXIT to request termination.
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; 2 - GHCB_CPUID_RESPONSE not received
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;
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mov eax, 2
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SevEsIdtTerminate:
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;
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; Use VMGEXIT to request termination. At this point the reason code is
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; located in EAX, so shift it left 16 bits to the proper location.
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;
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; EAX[11:0] => 0x100 - request termination
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; EAX[15:12] => 0x1 - OVMF
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; EAX[23:16] => 0xXX - REASON CODE
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;
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shl eax, 16
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or eax, 0x1100
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xor edx, edx
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mov ecx, 0xc0010130
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wrmsr
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;
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; Issue VMGEXIT - NASM doesn't support the vmmcall instruction in 32-bit
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; mode, so work around this by temporarily switching to 64-bit mode.
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;
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BITS 64
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rep vmmcall
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BITS 32
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;
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; We shouldn't come back from the VMGEXIT, but if we do, just loop.
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;
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SevEsIdtHlt:
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hlt
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jmp SevEsIdtHlt
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iret
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;
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; Total stack usage for the #VC handler is 44 bytes:
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; - 12 bytes for the exception IRET (after popping error code)
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; - 32 bytes for the local variables.
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;
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SevEsIdtVmmComm:
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;
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; If we're here, then we are an SEV-ES guest and this
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; was triggered by a CPUID instruction
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;
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; Set the first byte of the workarea to one to communicate that
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; a #VC was taken.
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mov byte[SEV_ES_WORK_AREA], 1
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pop ecx ; Error code
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cmp ecx, 0x72 ; Be sure it was CPUID
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jne SevEsIdtNotCpuid
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; Set up local variable room on the stack
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; CPUID function : + 28
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; CPUID request register : + 24
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; GHCB MSR (EAX) : + 20
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; GHCB MSR (EDX) : + 16
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; CPUID result (EDX) : + 12
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; CPUID result (ECX) : + 8
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; CPUID result (EBX) : + 4
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; CPUID result (EAX) : + 0
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sub esp, VC_VARIABLE_SIZE
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; Save the CPUID function being requested
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mov [esp + VC_CPUID_FUNCTION], eax
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; The GHCB CPUID protocol uses the following mapping to request
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; a specific register:
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; 0 => EAX, 1 => EBX, 2 => ECX, 3 => EDX
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;
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; Set EAX as the first register to request. This will also be used as a
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; loop variable to request all register values (EAX to EDX).
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xor eax, eax
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mov [esp + VC_CPUID_REQUEST_REGISTER], eax
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; Save current GHCB MSR value
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mov ecx, 0xc0010130
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rdmsr
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mov [esp + VC_GHCB_MSR_EAX], eax
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mov [esp + VC_GHCB_MSR_EDX], edx
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NextReg:
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;
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; Setup GHCB MSR
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; GHCB_MSR[63:32] = CPUID function
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; GHCB_MSR[31:30] = CPUID register
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; GHCB_MSR[11:0] = CPUID request protocol
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;
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mov eax, [esp + VC_CPUID_REQUEST_REGISTER]
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cmp eax, 4
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jge VmmDone
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shl eax, GHCB_CPUID_REGISTER_SHIFT
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or eax, GHCB_CPUID_REQUEST
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mov edx, [esp + VC_CPUID_FUNCTION]
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mov ecx, 0xc0010130
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wrmsr
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;
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; Issue VMGEXIT - NASM doesn't support the vmmcall instruction in 32-bit
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; mode, so work around this by temporarily switching to 64-bit mode.
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;
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BITS 64
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rep vmmcall
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BITS 32
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;
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; Read GHCB MSR
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; GHCB_MSR[63:32] = CPUID register value
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; GHCB_MSR[31:30] = CPUID register
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; GHCB_MSR[11:0] = CPUID response protocol
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;
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mov ecx, 0xc0010130
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rdmsr
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mov ecx, eax
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and ecx, 0xfff
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cmp ecx, GHCB_CPUID_RESPONSE
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jne SevEsIdtNoCpuidResponse
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; Save returned value
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shr eax, GHCB_CPUID_REGISTER_SHIFT
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mov [esp + eax * 4], edx
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; Next register
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inc word [esp + VC_CPUID_REQUEST_REGISTER]
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jmp NextReg
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VmmDone:
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;
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; At this point we have all CPUID register values. Restore the GHCB MSR,
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; set the return register values and return.
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;
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mov eax, [esp + VC_GHCB_MSR_EAX]
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mov edx, [esp + VC_GHCB_MSR_EDX]
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mov ecx, 0xc0010130
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wrmsr
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mov eax, [esp + VC_CPUID_RESULT_EAX]
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mov ebx, [esp + VC_CPUID_RESULT_EBX]
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mov ecx, [esp + VC_CPUID_RESULT_ECX]
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mov edx, [esp + VC_CPUID_RESULT_EDX]
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add esp, VC_VARIABLE_SIZE
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; Update the EIP value to skip over the now handled CPUID instruction
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; (the CPUID instruction has a length of 2)
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add word [esp], CPUID_INSN_LEN
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iret
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ALIGN 2
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Idtr:
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dw IDT_END - IDT_BASE - 1 ; Limit
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dd ADDR_OF(IDT_BASE) ; Base
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IdtrClear:
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dw 0 ; Limit
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dd 0 ; Base
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ALIGN 16
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;
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; The Interrupt Descriptor Table (IDT)
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; This will be used to determine if SEV-ES is enabled. Upon execution
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; of the CPUID instruction, a VMM Communication Exception will occur.
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; This will tell us if SEV-ES is enabled. We can use the current value
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; of the GHCB MSR to determine the SEV attributes.
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;
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IDT_BASE:
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;
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; Vectors 0 - 28 (No handlers)
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;
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%rep 29
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dw 0 ; Offset low bits 15..0
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dw 0x10 ; Selector
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db 0 ; Reserved
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db 0x8E ; Gate Type (IA32_IDT_GATE_TYPE_INTERRUPT_32)
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dw 0 ; Offset high bits 31..16
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%endrep
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;
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; Vector 29 (VMM Communication Exception)
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;
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dw (ADDR_OF(SevEsIdtVmmComm) & 0xffff) ; Offset low bits 15..0
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dw 0x10 ; Selector
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db 0 ; Reserved
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db 0x8E ; Gate Type (IA32_IDT_GATE_TYPE_INTERRUPT_32)
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dw (ADDR_OF(SevEsIdtVmmComm) >> 16) ; Offset high bits 31..16
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;
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; Vectors 30 - 31 (No handlers)
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;
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%rep 2
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dw 0 ; Offset low bits 15..0
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dw 0x10 ; Selector
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db 0 ; Reserved
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db 0x8E ; Gate Type (IA32_IDT_GATE_TYPE_INTERRUPT_32)
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dw 0 ; Offset high bits 31..16
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%endrep
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IDT_END:
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@ -37,182 +37,6 @@ BITS 32
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PAGE_READ_WRITE + \
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PAGE_PRESENT)
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;
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; SEV-ES #VC exception handler support
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;
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; #VC handler local variable locations
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;
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%define VC_CPUID_RESULT_EAX 0
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%define VC_CPUID_RESULT_EBX 4
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%define VC_CPUID_RESULT_ECX 8
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%define VC_CPUID_RESULT_EDX 12
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%define VC_GHCB_MSR_EDX 16
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%define VC_GHCB_MSR_EAX 20
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%define VC_CPUID_REQUEST_REGISTER 24
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%define VC_CPUID_FUNCTION 28
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; #VC handler total local variable size
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;
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%define VC_VARIABLE_SIZE 32
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; #VC handler GHCB CPUID request/response protocol values
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;
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%define GHCB_CPUID_REQUEST 4
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%define GHCB_CPUID_RESPONSE 5
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%define GHCB_CPUID_REGISTER_SHIFT 30
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%define CPUID_INSN_LEN 2
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; Check if Secure Encrypted Virtualization (SEV) features are enabled.
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;
|
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; Register usage is tight in this routine, so multiple calls for the
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; same CPUID and MSR data are performed to keep things simple.
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;
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; Modified: EAX, EBX, ECX, EDX, ESP
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;
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; If SEV is enabled then EAX will be at least 32.
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; If SEV is disabled then EAX will be zero.
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;
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CheckSevFeatures:
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; Set the first byte of the workarea to zero to communicate to the SEC
|
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; phase that SEV-ES is not enabled. If SEV-ES is enabled, the CPUID
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; instruction will trigger a #VC exception where the first byte of the
|
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; workarea will be set to one or, if CPUID is not being intercepted,
|
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; the MSR check below will set the first byte of the workarea to one.
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mov byte[SEV_ES_WORK_AREA], 0
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;
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; Set up exception handlers to check for SEV-ES
|
||||
; Load temporary RAM stack based on PCDs (see SevEsIdtVmmComm for
|
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; stack usage)
|
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; Establish exception handlers
|
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;
|
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mov esp, SEV_ES_VC_TOP_OF_STACK
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mov eax, ADDR_OF(Idtr)
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lidt [cs:eax]
|
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|
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; Check if we have a valid (0x8000_001F) CPUID leaf
|
||||
; CPUID raises a #VC exception if running as an SEV-ES guest
|
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mov eax, 0x80000000
|
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cpuid
|
||||
|
||||
; This check should fail on Intel or Non SEV AMD CPUs. In future if
|
||||
; Intel CPUs supports this CPUID leaf then we are guranteed to have exact
|
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; same bit definition.
|
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cmp eax, 0x8000001f
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jl NoSev
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|
||||
; Check for SEV memory encryption feature:
|
||||
; CPUID Fn8000_001F[EAX] - Bit 1
|
||||
; CPUID raises a #VC exception if running as an SEV-ES guest
|
||||
mov eax, 0x8000001f
|
||||
cpuid
|
||||
bt eax, 1
|
||||
jnc NoSev
|
||||
|
||||
; Check if SEV memory encryption is enabled
|
||||
; MSR_0xC0010131 - Bit 0 (SEV enabled)
|
||||
mov ecx, 0xc0010131
|
||||
rdmsr
|
||||
bt eax, 0
|
||||
jnc NoSev
|
||||
|
||||
; Check for SEV-ES memory encryption feature:
|
||||
; CPUID Fn8000_001F[EAX] - Bit 3
|
||||
; CPUID raises a #VC exception if running as an SEV-ES guest
|
||||
mov eax, 0x8000001f
|
||||
cpuid
|
||||
bt eax, 3
|
||||
jnc GetSevEncBit
|
||||
|
||||
; Check if SEV-ES is enabled
|
||||
; MSR_0xC0010131 - Bit 1 (SEV-ES enabled)
|
||||
mov ecx, 0xc0010131
|
||||
rdmsr
|
||||
bt eax, 1
|
||||
jnc GetSevEncBit
|
||||
|
||||
; Set the first byte of the workarea to one to communicate to the SEC
|
||||
; phase that SEV-ES is enabled.
|
||||
mov byte[SEV_ES_WORK_AREA], 1
|
||||
|
||||
GetSevEncBit:
|
||||
; Get pte bit position to enable memory encryption
|
||||
; CPUID Fn8000_001F[EBX] - Bits 5:0
|
||||
;
|
||||
and ebx, 0x3f
|
||||
mov eax, ebx
|
||||
|
||||
; The encryption bit position is always above 31
|
||||
sub ebx, 32
|
||||
jns SevSaveMask
|
||||
|
||||
; Encryption bit was reported as 31 or below, enter a HLT loop
|
||||
SevEncBitLowHlt:
|
||||
cli
|
||||
hlt
|
||||
jmp SevEncBitLowHlt
|
||||
|
||||
SevSaveMask:
|
||||
xor edx, edx
|
||||
bts edx, ebx
|
||||
|
||||
mov dword[SEV_ES_WORK_AREA_ENC_MASK], 0
|
||||
mov dword[SEV_ES_WORK_AREA_ENC_MASK + 4], edx
|
||||
jmp SevExit
|
||||
|
||||
NoSev:
|
||||
;
|
||||
; Perform an SEV-ES sanity check by seeing if a #VC exception occurred.
|
||||
;
|
||||
cmp byte[SEV_ES_WORK_AREA], 0
|
||||
jz NoSevPass
|
||||
|
||||
;
|
||||
; A #VC was received, yet CPUID indicates no SEV-ES support, something
|
||||
; isn't right.
|
||||
;
|
||||
NoSevEsVcHlt:
|
||||
cli
|
||||
hlt
|
||||
jmp NoSevEsVcHlt
|
||||
|
||||
NoSevPass:
|
||||
xor eax, eax
|
||||
|
||||
SevExit:
|
||||
;
|
||||
; Clear exception handlers and stack
|
||||
;
|
||||
push eax
|
||||
mov eax, ADDR_OF(IdtrClear)
|
||||
lidt [cs:eax]
|
||||
pop eax
|
||||
mov esp, 0
|
||||
|
||||
OneTimeCallRet CheckSevFeatures
|
||||
|
||||
; Check if Secure Encrypted Virtualization - Encrypted State (SEV-ES) feature
|
||||
; is enabled.
|
||||
;
|
||||
; Modified: EAX
|
||||
;
|
||||
; If SEV-ES is enabled then EAX will be non-zero.
|
||||
; If SEV-ES is disabled then EAX will be zero.
|
||||
;
|
||||
IsSevEsEnabled:
|
||||
xor eax, eax
|
||||
|
||||
; During CheckSevFeatures, the SEV_ES_WORK_AREA was set to 1 if
|
||||
; SEV-ES is enabled.
|
||||
cmp byte[SEV_ES_WORK_AREA], 1
|
||||
jne SevEsDisabled
|
||||
|
||||
mov eax, 1
|
||||
|
||||
SevEsDisabled:
|
||||
OneTimeCallRet IsSevEsEnabled
|
||||
|
||||
;
|
||||
; Modified: EAX, EBX, ECX, EDX
|
||||
;
|
||||
|
@ -324,218 +148,3 @@ SetCr3:
|
|||
mov cr3, eax
|
||||
|
||||
OneTimeCallRet SetCr3ForPageTables64
|
||||
|
||||
;
|
||||
; Start of #VC exception handling routines
|
||||
;
|
||||
|
||||
SevEsIdtNotCpuid:
|
||||
;
|
||||
; Use VMGEXIT to request termination.
|
||||
; 1 - #VC was not for CPUID
|
||||
;
|
||||
mov eax, 1
|
||||
jmp SevEsIdtTerminate
|
||||
|
||||
SevEsIdtNoCpuidResponse:
|
||||
;
|
||||
; Use VMGEXIT to request termination.
|
||||
; 2 - GHCB_CPUID_RESPONSE not received
|
||||
;
|
||||
mov eax, 2
|
||||
|
||||
SevEsIdtTerminate:
|
||||
;
|
||||
; Use VMGEXIT to request termination. At this point the reason code is
|
||||
; located in EAX, so shift it left 16 bits to the proper location.
|
||||
;
|
||||
; EAX[11:0] => 0x100 - request termination
|
||||
; EAX[15:12] => 0x1 - OVMF
|
||||
; EAX[23:16] => 0xXX - REASON CODE
|
||||
;
|
||||
shl eax, 16
|
||||
or eax, 0x1100
|
||||
xor edx, edx
|
||||
mov ecx, 0xc0010130
|
||||
wrmsr
|
||||
;
|
||||
; Issue VMGEXIT - NASM doesn't support the vmmcall instruction in 32-bit
|
||||
; mode, so work around this by temporarily switching to 64-bit mode.
|
||||
;
|
||||
BITS 64
|
||||
rep vmmcall
|
||||
BITS 32
|
||||
|
||||
;
|
||||
; We shouldn't come back from the VMGEXIT, but if we do, just loop.
|
||||
;
|
||||
SevEsIdtHlt:
|
||||
hlt
|
||||
jmp SevEsIdtHlt
|
||||
iret
|
||||
|
||||
;
|
||||
; Total stack usage for the #VC handler is 44 bytes:
|
||||
; - 12 bytes for the exception IRET (after popping error code)
|
||||
; - 32 bytes for the local variables.
|
||||
;
|
||||
SevEsIdtVmmComm:
|
||||
;
|
||||
; If we're here, then we are an SEV-ES guest and this
|
||||
; was triggered by a CPUID instruction
|
||||
;
|
||||
; Set the first byte of the workarea to one to communicate that
|
||||
; a #VC was taken.
|
||||
mov byte[SEV_ES_WORK_AREA], 1
|
||||
|
||||
pop ecx ; Error code
|
||||
cmp ecx, 0x72 ; Be sure it was CPUID
|
||||
jne SevEsIdtNotCpuid
|
||||
|
||||
; Set up local variable room on the stack
|
||||
; CPUID function : + 28
|
||||
; CPUID request register : + 24
|
||||
; GHCB MSR (EAX) : + 20
|
||||
; GHCB MSR (EDX) : + 16
|
||||
; CPUID result (EDX) : + 12
|
||||
; CPUID result (ECX) : + 8
|
||||
; CPUID result (EBX) : + 4
|
||||
; CPUID result (EAX) : + 0
|
||||
sub esp, VC_VARIABLE_SIZE
|
||||
|
||||
; Save the CPUID function being requested
|
||||
mov [esp + VC_CPUID_FUNCTION], eax
|
||||
|
||||
; The GHCB CPUID protocol uses the following mapping to request
|
||||
; a specific register:
|
||||
; 0 => EAX, 1 => EBX, 2 => ECX, 3 => EDX
|
||||
;
|
||||
; Set EAX as the first register to request. This will also be used as a
|
||||
; loop variable to request all register values (EAX to EDX).
|
||||
xor eax, eax
|
||||
mov [esp + VC_CPUID_REQUEST_REGISTER], eax
|
||||
|
||||
; Save current GHCB MSR value
|
||||
mov ecx, 0xc0010130
|
||||
rdmsr
|
||||
mov [esp + VC_GHCB_MSR_EAX], eax
|
||||
mov [esp + VC_GHCB_MSR_EDX], edx
|
||||
|
||||
NextReg:
|
||||
;
|
||||
; Setup GHCB MSR
|
||||
; GHCB_MSR[63:32] = CPUID function
|
||||
; GHCB_MSR[31:30] = CPUID register
|
||||
; GHCB_MSR[11:0] = CPUID request protocol
|
||||
;
|
||||
mov eax, [esp + VC_CPUID_REQUEST_REGISTER]
|
||||
cmp eax, 4
|
||||
jge VmmDone
|
||||
|
||||
shl eax, GHCB_CPUID_REGISTER_SHIFT
|
||||
or eax, GHCB_CPUID_REQUEST
|
||||
mov edx, [esp + VC_CPUID_FUNCTION]
|
||||
mov ecx, 0xc0010130
|
||||
wrmsr
|
||||
|
||||
;
|
||||
; Issue VMGEXIT - NASM doesn't support the vmmcall instruction in 32-bit
|
||||
; mode, so work around this by temporarily switching to 64-bit mode.
|
||||
;
|
||||
BITS 64
|
||||
rep vmmcall
|
||||
BITS 32
|
||||
|
||||
;
|
||||
; Read GHCB MSR
|
||||
; GHCB_MSR[63:32] = CPUID register value
|
||||
; GHCB_MSR[31:30] = CPUID register
|
||||
; GHCB_MSR[11:0] = CPUID response protocol
|
||||
;
|
||||
mov ecx, 0xc0010130
|
||||
rdmsr
|
||||
mov ecx, eax
|
||||
and ecx, 0xfff
|
||||
cmp ecx, GHCB_CPUID_RESPONSE
|
||||
jne SevEsIdtNoCpuidResponse
|
||||
|
||||
; Save returned value
|
||||
shr eax, GHCB_CPUID_REGISTER_SHIFT
|
||||
mov [esp + eax * 4], edx
|
||||
|
||||
; Next register
|
||||
inc word [esp + VC_CPUID_REQUEST_REGISTER]
|
||||
|
||||
jmp NextReg
|
||||
|
||||
VmmDone:
|
||||
;
|
||||
; At this point we have all CPUID register values. Restore the GHCB MSR,
|
||||
; set the return register values and return.
|
||||
;
|
||||
mov eax, [esp + VC_GHCB_MSR_EAX]
|
||||
mov edx, [esp + VC_GHCB_MSR_EDX]
|
||||
mov ecx, 0xc0010130
|
||||
wrmsr
|
||||
|
||||
mov eax, [esp + VC_CPUID_RESULT_EAX]
|
||||
mov ebx, [esp + VC_CPUID_RESULT_EBX]
|
||||
mov ecx, [esp + VC_CPUID_RESULT_ECX]
|
||||
mov edx, [esp + VC_CPUID_RESULT_EDX]
|
||||
|
||||
add esp, VC_VARIABLE_SIZE
|
||||
|
||||
; Update the EIP value to skip over the now handled CPUID instruction
|
||||
; (the CPUID instruction has a length of 2)
|
||||
add word [esp], CPUID_INSN_LEN
|
||||
iret
|
||||
|
||||
ALIGN 2
|
||||
|
||||
Idtr:
|
||||
dw IDT_END - IDT_BASE - 1 ; Limit
|
||||
dd ADDR_OF(IDT_BASE) ; Base
|
||||
|
||||
IdtrClear:
|
||||
dw 0 ; Limit
|
||||
dd 0 ; Base
|
||||
|
||||
ALIGN 16
|
||||
|
||||
;
|
||||
; The Interrupt Descriptor Table (IDT)
|
||||
; This will be used to determine if SEV-ES is enabled. Upon execution
|
||||
; of the CPUID instruction, a VMM Communication Exception will occur.
|
||||
; This will tell us if SEV-ES is enabled. We can use the current value
|
||||
; of the GHCB MSR to determine the SEV attributes.
|
||||
;
|
||||
IDT_BASE:
|
||||
;
|
||||
; Vectors 0 - 28 (No handlers)
|
||||
;
|
||||
%rep 29
|
||||
dw 0 ; Offset low bits 15..0
|
||||
dw 0x10 ; Selector
|
||||
db 0 ; Reserved
|
||||
db 0x8E ; Gate Type (IA32_IDT_GATE_TYPE_INTERRUPT_32)
|
||||
dw 0 ; Offset high bits 31..16
|
||||
%endrep
|
||||
;
|
||||
; Vector 29 (VMM Communication Exception)
|
||||
;
|
||||
dw (ADDR_OF(SevEsIdtVmmComm) & 0xffff) ; Offset low bits 15..0
|
||||
dw 0x10 ; Selector
|
||||
db 0 ; Reserved
|
||||
db 0x8E ; Gate Type (IA32_IDT_GATE_TYPE_INTERRUPT_32)
|
||||
dw (ADDR_OF(SevEsIdtVmmComm) >> 16) ; Offset high bits 31..16
|
||||
;
|
||||
; Vectors 30 - 31 (No handlers)
|
||||
;
|
||||
%rep 2
|
||||
dw 0 ; Offset low bits 15..0
|
||||
dw 0x10 ; Selector
|
||||
db 0 ; Reserved
|
||||
db 0x8E ; Gate Type (IA32_IDT_GATE_TYPE_INTERRUPT_32)
|
||||
dw 0 ; Offset high bits 31..16
|
||||
%endrep
|
||||
IDT_END:
|
||||
|
|
|
@ -77,6 +77,7 @@
|
|||
%define SEV_ES_WORK_AREA_ENC_MASK (FixedPcdGet32 (PcdSevEsWorkAreaBase) + 16)
|
||||
%define SEV_ES_VC_TOP_OF_STACK (FixedPcdGet32 (PcdOvmfSecPeiTempRamBase) + FixedPcdGet32 (PcdOvmfSecPeiTempRamSize))
|
||||
%include "Ia32/Flat32ToFlat64.asm"
|
||||
%include "Ia32/AmdSev.asm"
|
||||
%include "Ia32/PageTables64.asm"
|
||||
%endif
|
||||
|
||||
|
|
Loading…
Reference in New Issue