Messages in this thread | | | From | Punit Agrawal <> | Subject | Re: [PATCH v3 6/9] kvm: arm/arm64: Add host pmu to support VM introspection | Date | Wed, 18 Jan 2017 13:06:50 +0000 |
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Hi Marc,
Marc Zyngier <marc.zyngier@arm.com> writes:
> +Mark > > On 10/01/17 11:38, Punit Agrawal wrote: >> Both AArch32 and AArch64 mode of the ARMv8 architecture support trapping >> certain VM operations, e.g, TLB and cache maintenance >> operations. Selective trapping of these operations for specific VMs can >> be used to track the frequency with which these occur during execution. >> >> Add a software PMU on the host that can support tracking VM >> operations (in the form of PMU events). Supporting new events requires >> providing callbacks to configure the VM to enable/disable the trapping >> and read a count of the frequency. >> >> The host PMU events can be controlled by tools like perf that use >> standard kernel perf interfaces. >> >> Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> >> Cc: Christoffer Dall <christoffer.dall@linaro.org> >> Cc: Marc Zyngier <marc.zyngier@arm.com> >> Cc: Will Deacon <will.deacon@arm.com> >> --- >> arch/arm/include/asm/kvm_host.h | 8 ++ >> arch/arm/kvm/arm.c | 2 + >> arch/arm64/include/asm/kvm_host.h | 8 ++ >> virt/kvm/arm/host_pmu.c | 272 ++++++++++++++++++++++++++++++++++++++ >> 4 files changed, 290 insertions(+) >> create mode 100644 virt/kvm/arm/host_pmu.c >>
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>> > > This patch really makes me think that there is nothing arm-specific in > here at all. Why can't it be a generic feature through which > architectures can expose events in a generic way (or as close as > possible to being generic)?
I wasn't sure if other architectures are interested in the functionality - that's the only reason. Having said that, it can be turned off in the config so there shouldn't be any complaints.
I'll move this to virt/kvm in the next incarnation.
Thanks for taking a look.
> > Thanks, > > M.
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