Hi Mark Z.,
On 3/2/2017 4:05 AM, Marc Zyngier wrote:
On 01/03/17 21:36, Leeder, Neil wrote:
On 3/1/2017 1:10 PM, Mark Rutland wrote:
KVM already has (architected) PMU support, and without a corresponding
KVM patch this is at best insufficient. I don't imagine the KVM folk
will be too thrilled about the prospect of emulating an IMPLEMENTATION
DEFINED CPU feature like this.
Does KVM handle ARMv7 PMU implementations? If so, do you know what it
does for the scorpion_* and krait_* implementations in
arch/arm/kernel/perf_events_v7.c? These extensions in ARMv8 are very
similar to the krait extensions, with some 64-bit tweaks, so could be
handled by KVM the same way it handles the ARMv7 cases.
No, KVM doesn't handle the ARMv7 PMU at all. I'm not aware of the
virtualization extensions being available on Scorpion or Krait, which
makes it a moot point. What it handles is the PMUv3 architecture.
Thank you for the explanation.
This driver is specifically for Qualcomm Technologies server chips. They
will not be in a heterogenous environment with non-Qualcomm processors,
so there should be no migration issues.
If we were to provide a patch which added KVM support for the 4
additional registers here, would you consider reviewing it, or is adding
implementation-defined registers a show-stopper?
Thanks,
Neil
--
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.
