Messages in this thread Patch in this message | | | From | Huaitong Han <> | Subject | [PATCH] perf/x86/intel/pt: rdmsr before the CPUID test produces KVM warning | Date | Mon, 31 Aug 2015 16:21:02 +0800 |
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If KVM does not support INTEL_PT, guest MSR_IA32_RTIT_CTL reading will produce host warning like "kvm [2469]: vcpu0 unhandled rdmsr: 0x570".
Guest can determine whether the CPU supports Intel_PT according to CPUID, so test_cpu_cap function is added before rdmsr,and it is more in line with the code style.
Signed-off-by: Huaitong Han <huaitong.han@intel.com> Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
diff --git a/arch/x86/kernel/cpu/perf_event_intel_pt.c b/arch/x86/kernel/cpu/perf_event_intel_pt.c index 183de71..4cc6492 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_pt.c +++ b/arch/x86/kernel/cpu/perf_event_intel_pt.c @@ -123,9 +123,6 @@ static int __init pt_pmu_hw_init(void) long i; attrs = NULL; - ret = -ENODEV; - if (!test_cpu_cap(&boot_cpu_data, X86_FEATURE_INTEL_PT)) - goto fail; for (i = 0; i < PT_CPUID_LEAVES; i++) { cpuid_count(20, i, @@ -1061,6 +1058,10 @@ static __init int pt_init(void) int ret, cpu, prior_warn = 0; BUILD_BUG_ON(sizeof(struct topa) > PAGE_SIZE); + + if (!test_cpu_cap(&boot_cpu_data, X86_FEATURE_INTEL_PT)) + return -ENODEV; + get_online_cpus(); for_each_online_cpu(cpu) { u64 ctl; -- 2.4.3
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