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From: "Kang, Luwei" <luwei.kang@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"rkrcmar@redhat.com" <rkrcmar@redhat.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"joro@8bytes.org" <joro@8bytes.org>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"chao.p.peng@linux.intel.com" <chao.p.peng@linux.intel.com>
Subject: RE: [PATCH v7 05/13] perf/x86/intel/pt: Introduce a new function to get capability of Intel PT
Date: Thu, 3 May 2018 12:50:48 +0000	[thread overview]
Message-ID: <82D7661F83C1A047AF7DC287873BF1E167F6E0B4@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <349c6c61-6b6a-31b8-c8c5-24aed5716929@redhat.com>

> >> Can you elaborate on this, what information do we need besides
> >> MSR_IA32_VMX_MISC[14]?
> >
> > Enable Intel PT in guest depend on SECONDARY_EXEC_PT_USE_GPA, EPT,
> > MSR_IA32_VMX_MISC[14] and the capability of " PT_CAP_topa_output" on
> > hardware. PT driver will return " -ENODEV" if hardware not support
> > "PT_CAP_topa_output".
> 
> I actually don't understand why PT_CAP_topa_output matters for the purpose of enabling PT in the guest.  However you still need
> __pt_cap_get() in the CPUID checks.

Hi Paolo,
I think we should expose Intel Processor Trace to guest that can be detected and initialized. But without "PT_CAP_topa_output" Intel PT can't work in Linux.  So I add this feature as precondition. 
About why need this check in driver I think Alexander may know the reason.

Thanks,
Luwei Kang

> 
> Paolo

  reply	other threads:[~2018-05-03 12:50 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-03 12:08 [PATCH v7 00/13] Intel Processor Trace virtualization enabling Luwei Kang
2018-05-03 10:33 ` Alexander Shishkin
2018-05-03 12:08 ` [PATCH v7 01/13] perf/x86/intel/pt: Move Intel-PT MSRs bit definitions to a public header Luwei Kang
2018-05-03 12:08 ` [PATCH v7 02/13] perf/x86/intel/pt: Change pt_cap_get() to a public function Luwei Kang
2018-05-03 12:08 ` [PATCH v7 03/13] perf/x86/intel/pt: Add new bit definitions for Intel PT MSRs Luwei Kang
2018-05-03 12:08 ` [PATCH v7 04/13] perf/x86/intel/pt: add new capability for Intel PT Luwei Kang
2018-05-03 12:08 ` [PATCH v7 05/13] perf/x86/intel/pt: Introduce a new function to get capability of " Luwei Kang
2018-05-03 10:50   ` Alexander Shishkin
2018-05-03 11:04     ` Kang, Luwei
2018-05-03 12:13       ` Alexander Shishkin
2018-05-03 12:30         ` Paolo Bonzini
2018-05-03 12:30         ` Kang, Luwei
2018-05-03 12:32           ` Paolo Bonzini
2018-05-03 12:50             ` Kang, Luwei [this message]
2018-05-03 12:59               ` Alexander Shishkin
2018-05-03 12:08 ` [PATCH v7 06/13] KVM: x86: Add Intel Processor Trace virtualization mode Luwei Kang
2018-05-03 11:32   ` Alexander Shishkin
2018-05-03 11:50     ` Paolo Bonzini
2018-05-03 12:02       ` Alexander Shishkin
2018-05-03 12:30         ` Paolo Bonzini
2018-05-03 12:48           ` Alexander Shishkin
2018-05-03 12:50             ` Paolo Bonzini
2018-05-03 13:38               ` Alexander Shishkin
2018-05-03 13:48                 ` Paolo Bonzini
2018-05-04 10:38                   ` Alexander Shishkin
2018-05-04 21:52                     ` Paolo Bonzini
2018-05-04 10:45                 ` Peter Zijlstra
2018-05-04 21:44                   ` Paolo Bonzini
2018-05-04 22:15                     ` Peter Zijlstra
2018-05-07 10:47                       ` Paolo Bonzini
2018-05-03 11:52     ` Paolo Bonzini
2018-05-03 12:09       ` Alexander Shishkin
2018-05-03 12:31         ` Paolo Bonzini
2018-05-03 12:08 ` [PATCH v7 07/13] KVM: x86: Add Intel Processor Trace cpuid emulation Luwei Kang
2018-05-03 12:08 ` [PATCH v7 08/13] KVM: x86: Add Intel processor trace context for each vcpu Luwei Kang
2018-05-03 11:39   ` Alexander Shishkin
2018-05-03 11:53     ` Paolo Bonzini
2018-05-03 12:08 ` [PATCH v7 09/13] KVM: x86: Implement Intel Processor Trace context switch Luwei Kang
2018-05-04 10:29   ` Alexander Shishkin
2018-05-04 21:49     ` Paolo Bonzini
2018-05-03 12:08 ` [PATCH v7 10/13] KVM: x86: Introduce a function to initialize the PT configuration Luwei Kang
2018-05-03 12:08 ` [PATCH v7 11/13] KVM: x86: Implement Intel Processor Trace MSRs read/write Luwei Kang
2018-05-04 10:11   ` Alexander Shishkin
2018-05-04 21:47     ` Paolo Bonzini
2018-05-03 12:08 ` [PATCH v7 12/13] KVM: x86: Set intercept for Intel PT " Luwei Kang
2018-05-03 12:08 ` [PATCH v7 13/13] KVM: x86: Disable Intel Processor Trace when VMXON in L1 guest Luwei Kang
2018-05-04 10:23   ` Alexander Shishkin
2018-05-04 21:49     ` Paolo Bonzini
2018-05-03 12:13 [PATCH v7 00/13] Intel Processor Trace virtualization enabling Luwei Kang
2018-05-03 12:13 ` [PATCH v7 05/13] perf/x86/intel/pt: Introduce a new function to get capability of Intel PT Luwei Kang

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