From 73fdeb66592ee80dffb16fb8a9b7378a00c1a826 Mon Sep 17 00:00:00 2001 From: Huaitong Han Date: Mon, 31 Aug 2015 16:21:02 +0800 Subject: [PATCH] perf/x86/intel/pt: Fix KVM warning due to doing rdmsr() before the CPUID test 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 Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: acme@kernel.org Link: http://lkml.kernel.org/r/1441009262-9792-1-git-send-email-huaitong.han@intel.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event_intel_pt.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event_intel_pt.c b/arch/x86/kernel/cpu/perf_event_intel_pt.c index 42169283448b..868e1194337f 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_pt.c +++ b/arch/x86/kernel/cpu/perf_event_intel_pt.c @@ -139,9 +139,6 @@ 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, @@ -1130,6 +1127,10 @@ 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; -- 2.20.1