diff options
| -rw-r--r-- | OvmfPkg/ResetVector/Ia32/AmdSev.asm | 87 |
1 files changed, 45 insertions, 42 deletions
diff --git a/OvmfPkg/ResetVector/Ia32/AmdSev.asm b/OvmfPkg/ResetVector/Ia32/AmdSev.asm index 93ba917f36..aa95d06ead 100644 --- a/OvmfPkg/ResetVector/Ia32/AmdSev.asm +++ b/OvmfPkg/ResetVector/Ia32/AmdSev.asm @@ -38,6 +38,13 @@ BITS 32 %define SEV_GHCB_MSR 0xc0010130
%define SEV_STATUS_MSR 0xc0010131
+; The #VC was not for CPUID
+%define TERM_VC_NOT_CPUID 1
+
+; The unexpected response code
+%define TERM_UNEXPECTED_RESP_CODE 2
+
+
; Macro is used to issue the MSR protocol based VMGEXIT. The caller is
; responsible to populate values in the EDX:EAX registers. After the vmmcall
; returns, it verifies that the response code matches with the expected
@@ -73,6 +80,43 @@ BITS 32 jne SevEsUnexpectedRespTerminate
%endmacro
+; Macro to terminate the guest using the VMGEXIT.
+; arg 1: reason code
+%macro TerminateVmgExit 1
+ mov eax, %1
+ ;
+ ; 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, SEV_GHCB_MSR
+ 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.
+ ;
+%%TerminateHlt:
+ hlt
+ jmp %%TerminateHlt
+%endmacro
+
+; Terminate the guest due to unexpected response code.
+SevEsUnexpectedRespTerminate:
+ TerminateVmgExit TERM_UNEXPECTED_RESP_CODE
+
; Check if Secure Encrypted Virtualization (SEV) features are enabled.
;
; Register usage is tight in this routine, so multiple calls for the
@@ -227,48 +271,7 @@ SevEsDisabled: ;
SevEsIdtNotCpuid:
- ;
- ; Use VMGEXIT to request termination.
- ; 1 - #VC was not for CPUID
- ;
- mov eax, 1
- jmp SevEsIdtTerminate
-
-SevEsUnexpectedRespTerminate:
- ;
- ; Use VMGEXIT to request termination.
- ; 2 - Unexpected Response is 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, SEV_GHCB_MSR
- 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
+ TerminateVmgExit TERM_VC_NOT_CPUID
iret
;
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