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authorZhao Liu <zhao1.liu@intel.com>2024-04-24 23:49:15 +0800
committerPaolo Bonzini <pbonzini@redhat.com>2024-05-22 19:43:29 +0200
commit9a085c4b4adeec648d6506316b8a42fbd0cf7c3c (patch)
treebd795eca0fc821ca5f21b509d4a52cf2a23052a9 /target/i386/cpu.c
parent88dd4ca06c8392155289e5462cd26af3762a1b04 (diff)
i386/cpu: Use APIC ID info get NumSharingCache for CPUID[0x8000001D].EAX[bits 25:14]
The commit 8f4202fb1080 ("i386: Populate AMD Processor Cache Information for cpuid 0x8000001D") adds the cache topology for AMD CPU by encoding the number of sharing threads directly. From AMD's APM, NumSharingCache (CPUID[0x8000001D].EAX[bits 25:14]) means [1]: The number of logical processors sharing this cache is the value of this field incremented by 1. To determine which logical processors are sharing a cache, determine a Share Id for each processor as follows: ShareId = LocalApicId >> log2(NumSharingCache+1) Logical processors with the same ShareId then share a cache. If NumSharingCache+1 is not a power of two, round it up to the next power of two. From the description above, the calculation of this field should be same as CPUID[4].EAX[bits 25:14] for Intel CPUs. So also use the offsets of APIC ID to calculate this field. [1]: APM, vol.3, appendix.E.4.15 Function 8000_001Dh--Cache Topology Information Tested-by: Yongwei Ma <yongwei.ma@intel.com> Signed-off-by: Zhao Liu <zhao1.liu@intel.com> Reviewed-by: Babu Moger <babu.moger@amd.com> Tested-by: Babu Moger <babu.moger@amd.com> Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com> Message-ID: <20240424154929.1487382-8-zhao1.liu@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'target/i386/cpu.c')
-rw-r--r--target/i386/cpu.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index f3d2b8053b..22a8ca1c9b 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -331,7 +331,7 @@ static void encode_cache_cpuid8000001d(CPUCacheInfo *cache,
uint32_t *eax, uint32_t *ebx,
uint32_t *ecx, uint32_t *edx)
{
- uint32_t l3_threads;
+ uint32_t num_sharing_cache;
assert(cache->size == cache->line_size * cache->associativity *
cache->partitions * cache->sets);
@@ -340,11 +340,11 @@ static void encode_cache_cpuid8000001d(CPUCacheInfo *cache,
/* L3 is shared among multiple cores */
if (cache->level == 3) {
- l3_threads = topo_info->cores_per_die * topo_info->threads_per_core;
- *eax |= (l3_threads - 1) << 14;
+ num_sharing_cache = 1 << apicid_die_offset(topo_info);
} else {
- *eax |= ((topo_info->threads_per_core - 1) << 14);
+ num_sharing_cache = 1 << apicid_core_offset(topo_info);
}
+ *eax |= (num_sharing_cache - 1) << 14;
assert(cache->line_size > 0);
assert(cache->partitions > 0);