Acked-by: Jiewen Yao <jiewen....@intel.com>
> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Roth,
> Michael via groups.io
> Sent: Thursday, December 22, 2022 12:07 AM
> To: devel@edk2.groups.io
> Cc: Tom Lendacky <thomas.lenda...@amd.com>; Ni, Ray <ray...@intel.com>
> Subject: [edk2-devel] [PATCH 4/4] OvmfPkg/CcExitLib: Use documented
> XSave area base size for SEV-SNP
>
> Currently OVMF tries to rely on the base size advertised via the CPUID
> table entries corresponding to leaf 0xD, sub-leafs 0x0/0x1. This will
> generally work for KVM guests, but might not for other SEV-SNP
> hypervisor implementations. Make the handling more robust by simply
> using the base area size documented by the APM.
>
> Signed-off-by: Michael Roth <michael.r...@amd.com>
> ---
> OvmfPkg/Library/CcExitLib/CcExitVcHandler.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/OvmfPkg/Library/CcExitLib/CcExitVcHandler.c
> b/OvmfPkg/Library/CcExitLib/CcExitVcHandler.c
> index cd117d5a31..f985dcff8d 100644
> --- a/OvmfPkg/Library/CcExitLib/CcExitVcHandler.c
> +++ b/OvmfPkg/Library/CcExitLib/CcExitVcHandler.c
> @@ -1647,8 +1647,6 @@ SnpEnabled (
>
>
> @param[in] XFeaturesEnabled Bit-mask of enabled XSAVE
> features/areas as
>
> indicated by XCR0/MSR_IA32_XSS bits
>
> - @param[in] XSaveBaseSize Base/legacy XSAVE area size (e.g. when
>
> - XCR0 is 1)
>
> @param[in, out] XSaveSize Pointer to storage for calculated XSAVE
> area
>
> size
>
> @param[in] Compacted Whether or not the calculation is for the
>
> @@ -1663,7 +1661,6 @@ STATIC
> BOOLEAN
>
> GetCpuidXSaveSize (
>
> IN UINT64 XFeaturesEnabled,
>
> - IN UINT32 XSaveBaseSize,
>
> IN OUT UINT32 *XSaveSize,
>
> IN BOOLEAN Compacted
>
> )
>
> @@ -1672,7 +1669,10 @@ GetCpuidXSaveSize (
> UINT64 XFeaturesFound = 0;
>
> UINT32 Idx;
>
>
>
> - *XSaveSize = XSaveBaseSize;
>
> + //
>
> + // The base/legacy XSave size is documented to be 0x240 in the APM.
>
> + //
>
> + *XSaveSize = 0x240;
>
> CpuidInfo = (SEV_SNP_CPUID_INFO *)(UINT64)PcdGet32
> (PcdOvmfCpuidBase);
>
>
>
> for (Idx = 0; Idx < CpuidInfo->Count; Idx++) {
>
> @@ -1888,7 +1888,6 @@ GetCpuidFw (
>
>
> if (!GetCpuidXSaveSize (
>
> XCr0 | XssMsr.Uint64,
>
> - *Ebx,
>
> &XSaveSize,
>
> Compacted
>
> ))
>
> --
> 2.25.1
>
>
>
>
>
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