diff options
| author | Babu Moger <babu.moger@amd.com> | 2025-11-12 18:57:27 -0600 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2025-11-21 22:03:07 +0100 |
| commit | 3767def18f4cc394dc98cb93e78c3cc9afc4c515 (patch) | |
| tree | 9f9c42412a6f9531d5a1acf97d521ad441e6a035 | |
| parent | 5a88a6e92bbf5963fadeb0e8f8c747c2fb425ba8 (diff) | |
x86/cpufeatures: Add support for L3 Smart Data Cache Injection Allocation Enforcement
Smart Data Cache Injection (SDCI) is a mechanism that enables direct insertion
of data from I/O devices into the L3 cache. By directly caching data from I/O
devices rather than first storing the I/O data in DRAM, SDCI reduces demands on
DRAM bandwidth and reduces latency to the processor consuming the I/O data.
The SDCIAE (SDCI Allocation Enforcement) PQE feature allows system software to
control the portion of the L3 cache used for SDCI.
When enabled, SDCIAE forces all SDCI lines to be placed into the L3 cache
partitions identified by the highest-supported L3_MASK_n register, where n is
the maximum supported CLOSID.
Add CPUID feature bit that can be used to configure SDCIAE.
The SDCIAE feature details are documented in:
AMD64 Architecture Programmer's Manual Volume 2: System Programming
Publication # 24593 Revision 3.41 section 19.4.7 L3 Smart Data Cache
Injection Allocation Enforcement (SDCIAE).
available at https://bugzilla.kernel.org/show_bug.cgi?id=206537
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/83ca10d981c48e86df2c3ad9658bb3ba3544c763.1762995456.git.babu.moger@amd.com
| -rw-r--r-- | arch/x86/include/asm/cpufeatures.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/cpuid-deps.c | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/scattered.c | 1 |
3 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 4091a776e37a..2abee3e9dc75 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -500,6 +500,8 @@ #define X86_FEATURE_ABMC (21*32+15) /* Assignable Bandwidth Monitoring Counters */ #define X86_FEATURE_MSR_IMM (21*32+16) /* MSR immediate form instructions */ +#define X86_FEATURE_SDCIAE (21*32+18) /* L3 Smart Data Cache Injection Allocation Enforcement */ + /* * BUG word(s) */ diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c index 46efcbd6afa4..87e78586395b 100644 --- a/arch/x86/kernel/cpu/cpuid-deps.c +++ b/arch/x86/kernel/cpu/cpuid-deps.c @@ -72,6 +72,7 @@ static const struct cpuid_dep cpuid_deps[] = { { X86_FEATURE_CQM_MBM_LOCAL, X86_FEATURE_CQM_LLC }, { X86_FEATURE_BMEC, X86_FEATURE_CQM_MBM_TOTAL }, { X86_FEATURE_BMEC, X86_FEATURE_CQM_MBM_LOCAL }, + { X86_FEATURE_SDCIAE, X86_FEATURE_CAT_L3 }, { X86_FEATURE_AVX512_BF16, X86_FEATURE_AVX512VL }, { X86_FEATURE_AVX512_FP16, X86_FEATURE_AVX512BW }, { X86_FEATURE_ENQCMD, X86_FEATURE_XSAVES }, diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c index caa4dc885c21..d113863a8eab 100644 --- a/arch/x86/kernel/cpu/scattered.c +++ b/arch/x86/kernel/cpu/scattered.c @@ -53,6 +53,7 @@ static const struct cpuid_bit cpuid_bits[] = { { X86_FEATURE_SMBA, CPUID_EBX, 2, 0x80000020, 0 }, { X86_FEATURE_BMEC, CPUID_EBX, 3, 0x80000020, 0 }, { X86_FEATURE_ABMC, CPUID_EBX, 5, 0x80000020, 0 }, + { X86_FEATURE_SDCIAE, CPUID_EBX, 6, 0x80000020, 0 }, { X86_FEATURE_TSA_SQ_NO, CPUID_ECX, 1, 0x80000021, 0 }, { X86_FEATURE_TSA_L1_NO, CPUID_ECX, 2, 0x80000021, 0 }, { X86_FEATURE_AMD_WORKLOAD_CLASS, CPUID_EAX, 22, 0x80000021, 0 }, |