[edk2-devel] [PATCH 04/12] OvmfPkg/ResetVector: Perform a simple SEV-ES sanity check
Laszlo Ersek
lersek at redhat.com
Mon Jan 4 20:00:19 UTC 2021
On 12/15/20 21:51, Lendacky, Thomas wrote:
> From: Tom Lendacky <thomas.lendacky at amd.com>
>
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3108
>
> If a hypervisor incorrectly reports through CPUID that SEV-ES is not
> active, ensure that a #VC exception was not taken. If it is found that
> a #VC was taken, then the code enters a HLT loop.
>
> Cc: Jordan Justen <jordan.l.justen at intel.com>
> Cc: Laszlo Ersek <lersek at redhat.com>
> Cc: Ard Biesheuvel <ard.biesheuvel at arm.com>
> Cc: Brijesh Singh <brijesh.singh at amd.com>
> Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com>
> ---
> OvmfPkg/ResetVector/Ia32/PageTables64.asm | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/OvmfPkg/ResetVector/Ia32/PageTables64.asm b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
> index 3cd909df4f09..b08f31157cbf 100644
> --- a/OvmfPkg/ResetVector/Ia32/PageTables64.asm
> +++ b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
> @@ -153,6 +153,21 @@ SevEncBitLowHlt:
> jmp SevEncBitLowHlt
>
> 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:
> + hlt
> + jmp NoSevEsVcHlt
> +
> +NoSevPass:
> xor eax, eax
>
> SevExit:
>
(Please consider the CLI question for this patch as well.)
Reviewed-by: Laszlo Ersek <lersek at redhat.com>
Thanks
Laszlo
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