Re: [edk2-devel] [PATCH 2/2] UefiCpuPkg/MpInitLib: Copy SEV-ES save area pointer during APIC ID sorting

["Ni, Ray" <ray.ni@intel.com>]

Reviewed-by: Ray Ni <ray.ni@intel.com>

Thanks,
Ray
> -----Original Message-----
> From: Tom Lendacky <thomas.lendacky@amd.com>
> Sent: Tuesday, November 7, 2023 6:46 AM
> To: devel@edk2.groups.io
> Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>; Kumar,
> Rahul R <rahul.r.kumar@intel.com>; Gerd Hoffmann <kraxel@redhat.com>;
> Ard Biesheuvel <ardb+tianocore@kernel.org>; Michael Roth
> <michael.roth@amd.com>
> Subject: [PATCH 2/2] UefiCpuPkg/MpInitLib: Copy SEV-ES save area pointer
> during APIC ID sorting
> 
> With SEV-SNP, the SEV-ES save area for a vCPU should be unique to that
> vCPU. After commit 3323359a811a, the VMSA allocation was re-used, but
> when
> sorting the CPUs by APIC ID, the save area was not updated to follow the
> original CPU. Similar to the StartupApSignal address, the SevEsSaveArea
> address should be updated when sorting the CPUs.
> 
> This does not cause an issue at this time because all APs are in HLT state
> and then are (re)started at the same time, with the same VMSA contents.
> However, this should be fixed to account for any change in future
> behavior.
> 
> Fixes: 3323359a811a ("UefiCpuPkg/MpInitLib: Reuse VMSA allocation to ...")
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
>  UefiCpuPkg/Library/MpInitLib/MpLib.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c
> b/UefiCpuPkg/Library/MpInitLib/MpLib.c
> index 9a6ec5db5ce9..a41b9e5701af 100644
> --- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
> +++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
> @@ -370,6 +370,7 @@ SortApicId (
>    UINT32           ApCount;
>    CPU_INFO_IN_HOB  *CpuInfoInHob;
>    volatile UINT32  *StartupApSignal;
> +  VOID             *SevEsSaveArea;
> 
>    ApCount      = CpuMpData->CpuCount - 1;
>    CpuInfoInHob = (CPU_INFO_IN_HOB
> *)(UINTN)CpuMpData->CpuInfoInHob;
> @@ -397,12 +398,17 @@ SortApicId (
>          CopyMem (&CpuInfoInHob[Index1], &CpuInfo, sizeof
> (CPU_INFO_IN_HOB));
> 
>          //
> -        // Also exchange the StartupApSignal.
> +        // Also exchange the StartupApSignal and SevEsSaveArea.
>          //
>          StartupApSignal                            =
> CpuMpData->CpuData[Index3].StartupApSignal;
>          CpuMpData->CpuData[Index3].StartupApSignal =
>            CpuMpData->CpuData[Index1].StartupApSignal;
>          CpuMpData->CpuData[Index1].StartupApSignal = StartupApSignal;
> +
> +        SevEsSaveArea                            =
> CpuMpData->CpuData[Index3].SevEsSaveArea;
> +        CpuMpData->CpuData[Index3].SevEsSaveArea =
> +          CpuMpData->CpuData[Index1].SevEsSaveArea;
> +        CpuMpData->CpuData[Index1].SevEsSaveArea = SevEsSaveArea;
>        }
>      }
> 
> --
> 2.42.0



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