From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Luwei Kang <luwei.kang@intel.com>,
kvm@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com,
hpa@zytor.com, x86@kernel.org, rkrcmar@redhat.com,
linux-kernel@vger.kernel.org, joro@8bytes.org,
peterz@infradead.org, chao.p.peng@linux.intel.com
Subject: Re: [PATCH v7 06/13] KVM: x86: Add Intel Processor Trace virtualization mode
Date: Thu, 3 May 2018 15:02:15 +0300 [thread overview]
Message-ID: <20180503120215.dev7ti43zk7yoovn@um.fi.intel.com> (raw)
In-Reply-To: <47494e95-edcb-e8b5-0a32-004e9470dbdf@redhat.com>
On Thu, May 03, 2018 at 01:50:39PM +0200, Paolo Bonzini wrote:
> On 03/05/2018 13:32, Alexander Shishkin wrote:
> >>
> >> +/* Default is SYSTEM mode. */
> >> +static int __read_mostly pt_mode = PT_MODE_SYSTEM;
> >> +module_param(pt_mode, int, S_IRUGO);
> > So, it's an explicit module parameter? One apparent problem with this
> > is that one would need to reload kvm module(s) to be able to use PT,
> > which is not ideal.
>
> If you want to do tracing system-wide, that by definition must disable
> guest tracing,
Sure.
> so I think the module parameter is appropriate.
I don't see why. System-wide tracing takes place while perf record is
running. When it's done, it's done and we can un-disable the guest
tracing, without requiring the user to kill all their VMs and reload
modules.
Regards,
--
Alex
next prev parent reply other threads:[~2018-05-03 12:02 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
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 [this message]
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
-- strict thread matches above, loose matches on Subject: below --
2018-05-03 12:13 [PATCH v7 00/13] Intel Processor Trace virtualization enabling Luwei Kang
2018-05-03 12:13 ` [PATCH v7 06/13] KVM: x86: Add Intel Processor Trace virtualization mode Luwei Kang
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