61 lines
1.8 KiB
Diff
61 lines
1.8 KiB
Diff
From 6d36c9b1273980cb8ff511f78b5c9b126e4577da Mon Sep 17 00:00:00 2001
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From: May Shao <MayShao@zhaoxin.com>
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Date: Tue, 27 Sep 2022 20:44:48 +0800
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Subject: [PATCH 1/1] x86: Add the virtual machine detection in init_cacheinfo
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Use CPUID.01H.ECX[31] to indicate guest status.
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Set the default threads=1 to use non_temporal_threshold on
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vm and hosts with a single processor.
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Signed-off-by: May Shao <MayShao@zhaoxin.com>
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---
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sysdeps/x86/cacheinfo.c | 10 +++++++---
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1 file changed, 7 insertions(+), 3 deletions(-)
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diff --git a/sysdeps/x86/cacheinfo.c b/sysdeps/x86/cacheinfo.c
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index 7615334e..28bcf2f6 100644
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--- a/sysdeps/x86/cacheinfo.c
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+++ b/sysdeps/x86/cacheinfo.c
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@@ -495,7 +495,8 @@ init_cacheinfo (void)
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long int data = -1;
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long int shared = -1;
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unsigned int level;
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- unsigned int threads = 0;
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+ unsigned int threads = 1;
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+ unsigned int is_vm = 0;
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const struct cpu_features *cpu_features = __get_cpu_features ();
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int max_cpuid = cpu_features->max_cpuid;
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@@ -506,6 +507,9 @@ init_cacheinfo (void)
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long int core = handle_intel (_SC_LEVEL2_CACHE_SIZE, cpu_features);
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bool inclusive_cache = true;
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+ is_vm = ((cpu_features->cpuid[COMMON_CPUID_INDEX_1].ecx
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+ & (1 << 31)) >> 31);
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+
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/* Try L3 first. */
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level = 3;
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shared = handle_intel (_SC_LEVEL3_CACHE_SIZE, cpu_features);
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@@ -532,7 +536,7 @@ init_cacheinfo (void)
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/* A value of 0 for the HTT bit indicates there is only a single
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logical processor. */
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- if (HAS_CPU_FEATURE (HTT))
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+ if (HAS_CPU_FEATURE (HTT) && !is_vm)
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{
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/* Figure out the number of logical threads that share the
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highest cache level. */
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@@ -692,7 +696,7 @@ intel_bug_no_cache_info:
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shared /= threads;
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}
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else
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- threads = 1;
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+ threads = 1;
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/* Account for non-inclusive L2 and L3 caches. */
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if (!inclusive_cache)
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--
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2.17.1
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