I observe this with guest 3.13 and host 3.13
when running with -cpu host on my laptop:
[0.043000] Call Trace:
[0.043000] [] init_hw_perf_events+0x33/0x5cd
[0.043000] [] ? check_bugs+0x40/0x40
[0.043000] [] do_one_initcall+0x13a/0x190
[0.043000] [] ?
native_smp_prepare_cpus+
On Sun, Feb 02, 2014 at 10:59:30PM +0200, Michael S. Tsirkin wrote:
> I observe this with guest 3.13 and host 3.13
> when running with -cpu host on my laptop:
>
> [0.043000] Call Trace:
> [0.043000] [] init_hw_perf_events+0x33/0x5cd
> [0.043000] [] ? check_bugs+0x40/0x40
> [0.043
On Mon, Feb 03, 2014 at 10:58:28AM -0200, Eduardo Habkost wrote:
> Linux seems to be trying to read IA32_PERF_CAPABILITIES without checking the
> PDCM flag (CPUID[1].ECX[15]).
>
> I can't see why this wasn't crashing before, though. That code seems to be
> old.
>
>* v2 and above have a p
On Mon, Feb 03, 2014 at 10:58:28AM -0200, Eduardo Habkost wrote:
> On Sun, Feb 02, 2014 at 10:59:30PM +0200, Michael S. Tsirkin wrote:
> > I observe this with guest 3.13 and host 3.13
> > when running with -cpu host on my laptop:
> >
> > [0.043000] Call Trace:
> > [0.043000] [] init_hw_pe
Il 03/02/2014 15:06, Michael S. Tsirkin ha scritto:
Linux seems to be trying to read IA32_PERF_CAPABILITIES without checking the
PDCM flag (CPUID[1].ECX[15]).
I can't see why this wasn't crashing before, though. That code seems to be old.
* v2 and above have a perf capabilities MSR
On Mon, Feb 03, 2014 at 04:06:01PM +0200, Michael S. Tsirkin wrote:
> On Mon, Feb 03, 2014 at 10:58:28AM -0200, Eduardo Habkost wrote:
> > Where does the "v2 and above have a perf capabilities MSR" claim in the code
> > come from?
>
>
> But why doesn't it crash on baremetal?
> Probably baremetal
Il 03/02/2014 15:12, Peter Zijlstra ha scritto:
> But why doesn't it crash on baremetal?
> Probably baremetal simply returns 0 or something.
> Let me try ..
The claim "v2 and above have FEATURE_PDCM" is in fact true for real
hardware.
If it didn't the rdmsr() would have generated an exception a
On Mon, Feb 03, 2014 at 03:19:18PM +0100, Paolo Bonzini wrote:
> Il 03/02/2014 15:12, Peter Zijlstra ha scritto:
> >>> But why doesn't it crash on baremetal?
> >>> Probably baremetal simply returns 0 or something.
> >>> Let me try ..
> >The claim "v2 and above have FEATURE_PDCM" is in fact true for
On Mon, Feb 03, 2014 at 03:26:42PM +0100, Peter Zijlstra wrote:
> On Mon, Feb 03, 2014 at 03:19:18PM +0100, Paolo Bonzini wrote:
> > Il 03/02/2014 15:12, Peter Zijlstra ha scritto:
> > >>> But why doesn't it crash on baremetal?
> > >>> Probably baremetal simply returns 0 or something.
> > >>> Let m
On Mon, Feb 03, 2014 at 03:07:33PM +0100, Paolo Bonzini wrote:
> Il 03/02/2014 15:06, Michael S. Tsirkin ha scritto:
> >>Linux seems to be trying to read IA32_PERF_CAPABILITIES without checking the
> >>PDCM flag (CPUID[1].ECX[15]).
> >>
> >>I can't see why this wasn't crashing before, though. That
On Mon, Feb 03, 2014 at 03:26:42PM +0100, Peter Zijlstra wrote:
> On Mon, Feb 03, 2014 at 03:19:18PM +0100, Paolo Bonzini wrote:
> > Il 03/02/2014 15:12, Peter Zijlstra ha scritto:
> > >>> But why doesn't it crash on baremetal?
> > >>> Probably baremetal simply returns 0 or something.
> > >>> Let m
Il 03/02/2014 15:28, Peter Zijlstra ha scritto:
> > Right, and the virt thingy has no PEBS, so there is no correct value that we
> > could return from the MSR. That's why the CPUID bit is zero.
>
> There's more than PEBS in there, there's also the LBR format (which you
> obviously also don't ha
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