Messages in this thread Patch in this message | | | Date | Thu, 12 Nov 2015 12:06:44 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH] perf/x86/intel/pt: Test CPU vendor before loading |
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On Thu, Nov 12, 2015 at 11:56:12AM +0100, Borislav Petkov wrote: > diff --git a/arch/x86/kernel/cpu/perf_event_intel_pt.c b/arch/x86/kernel/cpu/perf_event_intel_pt.c > index 42169283448b..fa1262b025e7 100644 > --- a/arch/x86/kernel/cpu/perf_event_intel_pt.c > +++ b/arch/x86/kernel/cpu/perf_event_intel_pt.c > @@ -1129,6 +1129,9 @@ static __init int pt_init(void) > { > int ret, cpu, prior_warn = 0; > > + if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) > + return 0; > +
Does not apply; conflicts with:
commit 73fdeb66592ee80dffb16fb8a9b7378a00c1a826 Author: Huaitong Han <huaitong.han@intel.com> Date: Mon Aug 31 16:21:02 2015 +0800
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 <huaitong.han@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> 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 <mingo@kernel.org>
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;
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