linux-kernel - Re: [PATCH] perf/x86/intel/pt: Don't die on VMXON

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Message-ID: <874mbfym7f.fsf@ashishki-desk.ger.corp.intel.com>
Date:	Wed, 06 Apr 2016 15:07:48 +0300
From:	Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To:	Borislav Petkov <bp@...en8.de>,
	Peter Zijlstra <peterz@...radead.org>
Cc:	Gleb Natapov <gleb@...nel.org>,
	Paolo Bonzini <pbonzini@...hat.com>, x86@...nel.org,
	kvm@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
	linux-kernel@...r.kernel.org, tglx@...utronix.de, hpa@...or.com,
	Arnaldo Carvalho de Melo <acme@...radead.org>
Subject: Re: [PATCH] perf/x86/intel/pt: Don't die on VMXON

Borislav Petkov <bp@...en8.de> 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 & BIT(14))
>
> Also, I needz to consult my crystal ball about what bit 14 is...
>
> :-)

I know. It's right there in SDM chapter 36.5, referred to as "bit 14"
and it's not mentioned anywhere else that I could find, so I just left a
comment there.

Regards,
--
Alex