From: Paolo Bonzini <pbonzini@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>, Andi Kleen <ak@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>,
peterz@infradead.org, gleb@kernel.org, eranian@google.com,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/4] kvm: Implement PEBS virtualization
Date: Thu, 19 Jun 2014 16:42:43 +0200 [thread overview]
Message-ID: <53A2F6E3.6020703@redhat.com> (raw)
In-Reply-To: <20140610210654.GA16344@amt.cnet>
Il 10/06/2014 23:06, Marcelo Tosatti ha scritto:
> > BTW how about general PMU migration? As far as I can tell there
> > is no code to save/restore the state for that currently, right?
>
> Paolo wrote support for it, recently. Paolo?
Yes, on the KVM side all that is needed is to special case MSR reads and
writes that have side effects, for example:
case MSR_CORE_PERF_GLOBAL_STATUS:
if (msr_info->host_initiated) {
pmu->global_status = data;
return 0;
}
break; /* RO MSR */
case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
if (!(data & (pmu->global_ctrl_mask & ~(3ull<<62)))) {
if (!msr_info->host_initiated)
pmu->global_status &= ~data;
pmu->global_ovf_ctrl = data;
return 0;
}
break;
Right now this is only needed for writes.
Userspace then can read/write these MSRs, and add them to the migration
stream. QEMU has code for that.
Paolo
next prev parent reply other threads:[~2014-06-19 14:43 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-30 1:12 Implement PEBS virtualization for Silvermont Andi Kleen
2014-05-30 1:12 ` [PATCH 1/4] perf: Add PEBS virtualization enable " Andi Kleen
2014-05-30 1:12 ` [PATCH 2/4] perf: Allow guest PEBS for KVM owned counters Andi Kleen
2014-05-30 7:31 ` Peter Zijlstra
2014-05-30 16:03 ` Andi Kleen
2014-05-30 16:17 ` Peter Zijlstra
2014-05-30 1:12 ` [PATCH 3/4] perf: Handle guest PEBS events with a fake event Andi Kleen
2014-05-30 7:34 ` Peter Zijlstra
2014-05-30 16:29 ` Andi Kleen
2014-05-30 1:12 ` [PATCH 4/4] kvm: Implement PEBS virtualization Andi Kleen
2014-05-30 8:21 ` Gleb Natapov
2014-05-30 16:24 ` Andi Kleen
2014-06-02 16:45 ` Gleb Natapov
2014-06-02 16:52 ` Andi Kleen
2014-06-02 19:09 ` Marcelo Tosatti
2014-06-02 19:05 ` Eric Northup
2014-06-02 19:57 ` Andi Kleen
2014-06-19 14:39 ` Paolo Bonzini
2014-06-10 18:04 ` Marcelo Tosatti
2014-06-10 19:22 ` Andi Kleen
2014-06-10 21:06 ` Marcelo Tosatti
2014-06-19 14:42 ` Paolo Bonzini [this message]
2014-06-19 17:33 ` Andi Kleen
2014-06-19 20:33 ` Paolo Bonzini
2014-06-22 13:57 ` Avi Kivity
2014-06-22 19:02 ` Andi Kleen
2014-06-24 16:45 ` Marcelo Tosatti
2014-06-25 7:04 ` Avi Kivity
2014-05-30 7:39 ` Implement PEBS virtualization for Silvermont Peter Zijlstra
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