Reviewed-by: Ray Ni <ray...@intel.com>
Thanks,
Ray
> -----Original Message-----
> From: Wu, Jiaxin <jiaxin...@intel.com>
> Sent: Wednesday, November 15, 2023 7:16 PM
> To: devel@edk2.groups.io
> Cc: Laszlo Ersek <ler...@redhat.com>; Dong, Eric <eric.d...@intel.com>; Ni,
> Ray <ray...@intel.com>; Kumar, Rahul R <rahul.r.ku...@intel.com>; Gerd
> Hoffmann <kra...@redhat.com>; Zeng, Star <star.z...@intel.com>
> Subject: [PATCH v2 1/3] UefiCpuPkg/BaseXApicLib: Fix
> CPUID_V2_EXTENDED_TOPOLOGY detection
>
> This patch is to complete 170d4ce8, sync the change to BaseXApicLib.
>
> Checking the max cpuid leaf is not enough to figure whenever
> CPUID_V2_EXTENDED_TOPOLOGY is supported. Intel SDM says:
>
> Software must detect the presence of CPUID leaf 1FH by verifying
> (a) the highest leaf index supported by CPUID is >= 1FH, and
> (b) CPUID.1FH:EBX[15:0] reports a non-zero value.
>
> The same is true for CPUID leaf 0BH.
>
> This patch adds the EBX check to GetProcessorLocation2ByApicId(). The
> patch also fixes the existing check in GetProcessorLocationByApicId() to
> be in line with the spec by looking at bits 15:0. The comments are
> updated with a quote from the Intel SDM.
>
> Cc: Laszlo Ersek <ler...@redhat.com>
> Cc: Eric Dong <eric.d...@intel.com>
> Cc: Ray Ni <ray...@intel.com>
> Cc: Rahul Kumar <rahul1.ku...@intel.com>
> Cc: Gerd Hoffmann <kra...@redhat.com>
> Cc: Star Zeng <star.z...@intel.com>
> Signed-off-by: Gerd Hoffmann <kra...@redhat.com>
> Signed-off-by: Jiaxin Wu <jiaxin...@intel.com>
> ---
> UefiCpuPkg/Library/BaseXApicLib/BaseXApicLib.c | 21
> ++++++++++++++++-----
> 1 file changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/UefiCpuPkg/Library/BaseXApicLib/BaseXApicLib.c
> b/UefiCpuPkg/Library/BaseXApicLib/BaseXApicLib.c
> index d56c6275cc..efb9d71ca1 100644
> --- a/UefiCpuPkg/Library/BaseXApicLib/BaseXApicLib.c
> +++ b/UefiCpuPkg/Library/BaseXApicLib/BaseXApicLib.c
> @@ -1053,15 +1053,16 @@ GetProcessorLocationByApicId (
> &ExtendedTopologyEbx.Uint32,
> &ExtendedTopologyEcx.Uint32,
> NULL
> );
> //
> - // If CPUID.(EAX=0BH, ECX=0H):EBX returns zero and maximum input
> value for
> - // basic CPUID information is greater than 0BH, then CPUID.0BH leaf is
> not
> - // supported on that processor.
> + // Quoting Intel SDM:
> + // Software must detect the presence of CPUID leaf 0BH by
> + // verifying (a) the highest leaf index supported by CPUID is >=
> + // 0BH, and (b) CPUID.0BH:EBX[15:0] reports a non-zero value.
> //
> - if (ExtendedTopologyEbx.Uint32 != 0) {
> + if (ExtendedTopologyEbx.Bits.LogicalProcessors != 0) {
> TopologyLeafSupported = TRUE;
>
> //
> // Sub-leaf index 0 (ECX= 0 as input) provides enumeration
> parameters to extract
> // the SMT sub-field of x2APIC ID.
> @@ -1183,10 +1184,11 @@ GetProcessorLocation2ByApicId (
> OUT UINT32 *Core OPTIONAL,
> OUT UINT32 *Thread OPTIONAL
> )
> {
> CPUID_EXTENDED_TOPOLOGY_EAX ExtendedTopologyEax;
> + CPUID_EXTENDED_TOPOLOGY_EBX ExtendedTopologyEbx;
> CPUID_EXTENDED_TOPOLOGY_ECX ExtendedTopologyEcx;
> UINT32 MaxStandardCpuIdIndex;
> UINT32 Index;
> UINTN LevelType;
> UINT32
> Bits[CPUID_V2_EXTENDED_TOPOLOGY_LEVEL_TYPE_DIE + 2];
> @@ -1195,14 +1197,23 @@ GetProcessorLocation2ByApicId (
> for (LevelType = 0; LevelType < ARRAY_SIZE (Bits); LevelType++) {
> Bits[LevelType] = 0;
> }
>
> //
> - // Get max index of CPUID
> + // Quoting Intel SDM:
> + // Software must detect the presence of CPUID leaf 1FH by verifying
> + // (a) the highest leaf index supported by CPUID is >= 1FH, and (b)
> + // CPUID.1FH:EBX[15:0] reports a non-zero value.
> //
> AsmCpuid (CPUID_SIGNATURE, &MaxStandardCpuIdIndex, NULL, NULL,
> NULL);
> if (MaxStandardCpuIdIndex < CPUID_V2_EXTENDED_TOPOLOGY) {
> + ExtendedTopologyEbx.Bits.LogicalProcessors = 0;
> + } else {
> + AsmCpuidEx (CPUID_V2_EXTENDED_TOPOLOGY, 0, NULL,
> &ExtendedTopologyEbx.Uint32, NULL, NULL);
> + }
> +
> + if (ExtendedTopologyEbx.Bits.LogicalProcessors == 0) {
> if (Die != NULL) {
> *Die = 0;
> }
>
> if (Tile != NULL) {
> --
> 2.16.2.windows.1
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