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| author | Zhao Liu <zhao1.liu@intel.com> | 2025-07-11 18:21:26 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2025-07-12 15:28:21 +0200 |
| commit | 1034b94fe98da35857f261d4db89ce2ebed8c5c3 (patch) | |
| tree | df2bc2e95b3d2653dcf2eb898c9347b80eeccca2 | |
| parent | 7ff24fb657d35c014f735f69aef03810fde607ab (diff) | |
| download | qemu-1034b94fe98da35857f261d4db89ce2ebed8c5c3.zip qemu-1034b94fe98da35857f261d4db89ce2ebed8c5c3.tar.gz qemu-1034b94fe98da35857f261d4db89ce2ebed8c5c3.tar.bz2 | |
i386/cpu: Refine comment of CPUID2CacheDescriptorInfo
Refer to SDM vol.3 table 1-21, add the notes about the missing
descriptor, and fix the typo and comment format.
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Tested-by: Yi Lai <yi1.lai@intel.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250711102143.1622339-2-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | target/i386/cpu.c | 31 |
1 files changed, 22 insertions, 9 deletions
diff --git a/target/i386/cpu.c b/target/i386/cpu.c index f9e6bc8d..f107e58 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -68,6 +68,7 @@ struct CPUID2CacheDescriptorInfo { /* * Known CPUID 2 cache descriptors. + * TLB, prefetch and sectored cache related descriptors are not included. * From Intel SDM Volume 2A, CPUID instruction */ struct CPUID2CacheDescriptorInfo cpuid2_cache_descriptors[] = { @@ -89,18 +90,29 @@ struct CPUID2CacheDescriptorInfo cpuid2_cache_descriptors[] = { .associativity = 2, .line_size = 64, }, [0x21] = { .level = 2, .type = UNIFIED_CACHE, .size = 256 * KiB, .associativity = 8, .line_size = 64, }, - /* lines per sector is not supported cpuid2_cache_descriptor(), - * so descriptors 0x22, 0x23 are not included - */ + /* + * lines per sector is not supported cpuid2_cache_descriptor(), + * so descriptors 0x22, 0x23 are not included + */ [0x24] = { .level = 2, .type = UNIFIED_CACHE, .size = 1 * MiB, .associativity = 16, .line_size = 64, }, - /* lines per sector is not supported cpuid2_cache_descriptor(), - * so descriptors 0x25, 0x20 are not included - */ + /* + * lines per sector is not supported cpuid2_cache_descriptor(), + * so descriptors 0x25, 0x29 are not included + */ [0x2C] = { .level = 1, .type = DATA_CACHE, .size = 32 * KiB, .associativity = 8, .line_size = 64, }, [0x30] = { .level = 1, .type = INSTRUCTION_CACHE, .size = 32 * KiB, .associativity = 8, .line_size = 64, }, + /* + * Newer Intel CPUs (having the cores without L3, e.g., Intel MTL, ARL) + * use CPUID 0x4 leaf to describe cache topology, by encoding CPUID 0x2 + * leaf with 0xFF. For older CPUs (without 0x4 leaf), it's also valid + * to just ignore L3's code if there's no L3. + * + * This already covers all the cases in QEMU, so code 0x40 is not + * included. + */ [0x41] = { .level = 2, .type = UNIFIED_CACHE, .size = 128 * KiB, .associativity = 4, .line_size = 32, }, [0x42] = { .level = 2, .type = UNIFIED_CACHE, .size = 256 * KiB, @@ -138,9 +150,10 @@ struct CPUID2CacheDescriptorInfo cpuid2_cache_descriptors[] = { .associativity = 4, .line_size = 64, }, [0x78] = { .level = 2, .type = UNIFIED_CACHE, .size = 1 * MiB, .associativity = 4, .line_size = 64, }, - /* lines per sector is not supported cpuid2_cache_descriptor(), - * so descriptors 0x79, 0x7A, 0x7B, 0x7C are not included. - */ + /* + * lines per sector is not supported cpuid2_cache_descriptor(), + * so descriptors 0x79, 0x7A, 0x7B, 0x7C are not included. + */ [0x7D] = { .level = 2, .type = UNIFIED_CACHE, .size = 2 * MiB, .associativity = 8, .line_size = 64, }, [0x7F] = { .level = 2, .type = UNIFIED_CACHE, .size = 512 * KiB, |