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From: Zhao Liu <zhao1.liu@intel.com>
To: "Eduardo Habkost" <eduardo@habkost.net>,
	"Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>,
	"Yanan Wang" <wangyanan55@huawei.com>,
	"Michael S . Tsirkin" <mst@redhat.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Eric Blake" <eblake@redhat.com>,
	"Markus Armbruster" <armbru@redhat.com>,
	"Marcelo Tosatti" <mtosatti@redhat.com>,
	"Daniel P . Berrangé" <berrange@redhat.com>
Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org,
	Zhenyu Wang <zhenyu.z.wang@intel.com>,
	Zhuocheng Ding <zhuocheng.ding@intel.com>,
	Babu Moger <babu.moger@amd.com>,
	Xiaoyao Li <xiaoyao.li@intel.com>,
	Dapeng Mi <dapeng1.mi@intel.com>,
	Yongwei Ma <yongwei.ma@intel.com>, Zhao Liu <zhao1.liu@intel.com>
Subject: [PATCH v11 07/21] i386/cpu: Use APIC ID info get NumSharingCache for CPUID[0x8000001D].EAX[bits 25:14]
Date: Wed, 24 Apr 2024 23:49:15 +0800	[thread overview]
Message-ID: <20240424154929.1487382-8-zhao1.liu@intel.com> (raw)
In-Reply-To: <20240424154929.1487382-1-zhao1.liu@intel.com>

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>
---
Changes since v7:
 * Moved this patch after CPUID[4]'s similar change ("i386/cpu: Use APIC
   ID offset to encode cache topo in CPUID[4]"). (Xiaoyao)
 * Dropped Michael/Babu's Acked/Reviewed/Tested tags since the code
   change due to the rebase.
 * Re-added Yongwei's Tested tag For his re-testing (compilation on
   Intel platforms).

Changes since v3:
 * Rewrote the subject. (Babu)
 * Deleted the original "comment/help" expression, as this behavior is
   confirmed for AMD CPUs. (Babu)
 * Renamed "num_apic_ids" (v3) to "num_sharing_cache" to match spec
   definition. (Babu)

Changes since v1:
 * Renamed "l3_threads" to "num_apic_ids" in
   encode_cache_cpuid8000001d(). (Yanan)
 * Added the description of the original commit and add Cc.
---
 target/i386/cpu.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 93c2f56780f5..c13bfed28878 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);
-- 
2.34.1



  parent reply	other threads:[~2024-04-24 15:38 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-24 15:49 [PATCH v11 00/21] i386: Introduce smp.modules and clean up cache topology Zhao Liu
2024-04-24 15:49 ` [PATCH v11 01/21] hw/core/machine: Introduce the module as a CPU topology level Zhao Liu
2024-04-24 15:49 ` [PATCH v11 02/21] hw/core/machine: Support modules in -smp Zhao Liu
2024-04-24 15:49 ` [PATCH v11 03/21] hw/core: Introduce module-id as the topology subindex Zhao Liu
2024-04-24 15:49 ` [PATCH v11 04/21] hw/core: Support module-id in numa configuration Zhao Liu
2024-04-24 15:49 ` [PATCH v11 05/21] i386/cpu: Fix i/d-cache topology to core level for Intel CPU Zhao Liu
2024-04-24 15:49 ` [PATCH v11 06/21] i386/cpu: Use APIC ID info to encode cache topo in CPUID[4] Zhao Liu
2024-04-24 15:49 ` Zhao Liu [this message]
2024-04-24 15:49 ` [PATCH v11 08/21] i386/cpu: Consolidate the use of topo_info in cpu_x86_cpuid() Zhao Liu
2024-04-24 15:49 ` [PATCH v11 09/21] i386/cpu: Introduce bitmap to cache available CPU topology levels Zhao Liu
2024-04-24 15:49 ` [PATCH v11 10/21] i386: Split topology types of CPUID[0x1F] from the definitions of CPUID[0xB] Zhao Liu
2024-04-24 15:49 ` [PATCH v11 11/21] i386/cpu: Decouple CPUID[0x1F] subleaf with specific topology level Zhao Liu
2024-04-24 15:49 ` [PATCH v11 12/21] i386: Introduce module level cpu topology to CPUX86State Zhao Liu
2024-04-24 15:49 ` [PATCH v11 13/21] i386: Support modules_per_die in X86CPUTopoInfo Zhao Liu
2024-04-24 15:49 ` [PATCH v11 14/21] i386: Expose module level in CPUID[0x1F] Zhao Liu
2024-04-24 15:49 ` [PATCH v11 15/21] i386: Support module_id in X86CPUTopoIDs Zhao Liu
2024-04-24 15:49 ` [PATCH v11 16/21] i386/cpu: Introduce module-id to X86CPU Zhao Liu
2024-04-24 15:49 ` [PATCH v11 17/21] tests: Add test case of APIC ID for module level parsing Zhao Liu
2024-04-24 15:49 ` [PATCH v11 18/21] hw/i386/pc: Support smp.modules for x86 PC machine Zhao Liu
2024-04-24 15:49 ` [PATCH v11 19/21] i386: Add cache topology info in CPUCacheInfo Zhao Liu
2024-04-30  6:14   ` Tejus GK
2024-05-06  7:32     ` Zhao Liu
2024-04-24 15:49 ` [PATCH v11 20/21] i386/cpu: Use CPUCacheInfo.share_level to encode CPUID[4] Zhao Liu
2024-04-24 15:49 ` [PATCH v11 21/21] i386/cpu: Use CPUCacheInfo.share_level to encode CPUID[0x8000001D].EAX[bits 25:14] Zhao Liu
2024-04-25  8:06 ` [PATCH v11 00/21] i386: Introduce smp.modules and clean up cache topology Philippe Mathieu-Daudé
2024-04-25 13:30   ` Zhao Liu
2024-05-15 14:48 ` Zhao Liu

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