r, here's an updated patch against perf/urgent. It also doesn't
introduce new ACCESS_ONCE()s any more.
>From 89b85412c46270a675cf77918fc9fda520a7bdd2 Mon Sep 17 00:00:00 2001
From: Alexander Shishkin
Date: Tue, 29 Mar 2016 17:43:10 +0300
Subject: [PATCH] perf/x86/intel/pt: Don
* Alexander Shishkin wrote:
> Ingo Molnar writes:
>
> >> @@ -3144,6 +3146,8 @@ static void vmclear_local_loaded_vmcss(void)
> >> static void kvm_cpu_vmxoff(void)
> >> {
> >>asm volatile (__ex(ASM_VMX_VMXOFF) : : : "cc");
> >> +
> >> + intel_pt_vmx(0);
> >> }
> >
> > Yeah so the name in
Ingo Molnar writes:
>> @@ -3144,6 +3146,8 @@ static void vmclear_local_loaded_vmcss(void)
>> static void kvm_cpu_vmxoff(void)
>> {
>> asm volatile (__ex(ASM_VMX_VMXOFF) : : : "cc");
>> +
>> +intel_pt_vmx(0);
>> }
>
> Yeah so the name intel_pt_vmx() is pretty information-free because i
* Alexander Shishkin wrote:
> Signed-off-by: Alexander Shishkin
> ---
> arch/x86/events/intel/pt.c| 75
> +--
> arch/x86/events/intel/pt.h| 2 ++
> arch/x86/include/asm/perf_event.h | 4 +++
> arch/x86/kvm/vmx.c| 4 +++
>
s well.
3x a charm:
>From 1ac911d5096af88217b3a26b26d594b02f0db614 Mon Sep 17 00:00:00 2001
From: Alexander Shishkin
Date: Tue, 29 Mar 2016 17:43:10 +0300
Subject: [PATCH] perf/x86/intel/pt: Don't die on VMXON
Some versions of Intel PT do not support tracing across VMXON, more
specifically, VMXON wil
Borislav Petkov writes:
> On Wed, Apr 06, 2016 at 01:52:15PM +0200, Peter Zijlstra wrote:
>> Borislav tells me this ought to be boot_cpu_has(X86_FEATURE_VMX)
>>
>> > + /* Intel SDM, 36.5 "Tracing post-VMXON" */
>> > + rdmsrl(MSR_IA32_VMX_MISC, reg);
>> > + if (reg & BI
On Wed, Apr 06, 2016 at 01:52:15PM +0200, Peter Zijlstra wrote:
> Borislav tells me this ought to be boot_cpu_has(X86_FEATURE_VMX)
>
> > + /* Intel SDM, 36.5 "Tracing post-VMXON" */
> > + rdmsrl(MSR_IA32_VMX_MISC, reg);
> > + if (reg & BIT(14))
Also, I needz to consu
On Wed, Apr 06, 2016 at 02:10:49PM +0300, Alexander Shishkin wrote:
> >> + /* may be already stopped by a PMI*/
> >> + if (!(ctl & RTIT_CTL_TRACEEN))
> >> + return;
> >> +
> >> + ctl ^= RTIT_CTL_TRACEEN;
> >
> > Would that not be much less confusing when written like |= ?
>
> This one'
> argument name.
I did struggle with this one indeed.
How about this then:
>From 9faf95f173decda1f2e3101ced9d9370c14f2339 Mon Sep 17 00:00:00 2001
From: Alexander Shishkin
Date: Tue, 29 Mar 2016 17:43:10 +0300
Subject: [PATCH] perf/x86/intel/pt: Don't die on VMXON
Some versions of In
On Fri, Apr 01, 2016 at 07:24:14PM +0300, Alexander Shishkin wrote:
> +static void pt_config_stop(struct perf_event *event)
> {
> + u64 ctl = READ_ONCE(event->hw.config);
>
> + /* may be already stopped by a PMI*/
> + if (!(ctl & RTIT_CTL_TRACEEN))
> + return;
> +
> +
Some versions of Intel PT do not support tracing across VMXON, more
specifically, VMXON will clear TraceEn control bit and any attempt to
set it before VMXOFF will throw a #GP, which in the current state of
things will crash the kernel. Namely,
$ perf record -e intel_pt// kvm -nographic
on such a
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