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SubjectRe: [PATCH v3 0/4] KVM: x86: Use static calls to reduce kvm_pmu_ops overhead
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Knock knock, do we have any more comments on this patch set ?

On 7/3/2022 7:59 pm, Like Xu wrote:
> Hi,
>
> This is a successor to the previous patch set [1] from Jason Baron, which
> converts kvm_pmu_ops to use static_call. A typical perf use case [2] for
> an Intel guest shows good performance gains (results are in patch 0004).
>
> V2 -> V3 Changelog:
> - Refine commit messages for __initdata; (Sean)
> - Merge the logic of _defining_ and _update_; (Sean)
> - Drop EXPORT_SYMBOL_GPL(kvm_pmu_ops); (Sean)
> - Drop the _NULL() variant in the kvm-x86-*-ops.h; (Thanks to Paolo and Sean)
> - Drop to export kvm_pmu_is_valid_msr() for nVMX; (Thanks to Sean)
> - Based on the kvm/queue;
>
> V1 -> V2 Changelog:
> - Export kvm_pmu_is_valid_msr() for nVMX [Sean]
> - Land memcpy() above kvm_ops_static_call_update() [Sean]
> - Move the pmu_ops to kvm_x86_init_ops and tagged as __initdata. [Sean]
> - Move the kvm_ops_static_call_update() to x86.c [Sean]
> - Drop kvm_pmu_ops_static_call_update() [Sean]
> - Fix WARNING that macros KVM_X86_OP should not use a trailing semicolon
>
> Please note checkpatch.pl complains a lot about KVM_X86_*_OP macros:
> - WARNING: macros should not use a trailing semicolon
> - ERROR: Macros with multiple statements should be enclosed in a do - while loop
> which could be addressed as a one-time follow-up if needed.
>
> Previous:
> https://lore.kernel.org/kvm/20211108111032.24457-1-likexu@tencent.com/
>
> [1] https://lore.kernel.org/lkml/cover.1610680941.git.jbaron@akamai.com/
> [2] perf record -e branch-instructions -e branch-misses \
> -e cache-misses -e cache-references -e cpu-cycles \
> -e instructions ./workload
>
> Thanks,
>
> Like Xu (4):
> KVM: x86: Move kvm_ops_static_call_update() to x86.c
> KVM: x86: Copy kvm_pmu_ops by value to eliminate layer of indirection
> KVM: x86: Move .pmu_ops to kvm_x86_init_ops and tag as __initdata
> KVM: x86: Use static calls to reduce kvm_pmu_ops overhead
>
> arch/x86/include/asm/kvm-x86-pmu-ops.h | 31 +++++++++++++++++
> arch/x86/include/asm/kvm_host.h | 17 +--------
> arch/x86/kvm/pmu.c | 48 +++++++++++++++-----------
> arch/x86/kvm/pmu.h | 9 ++++-
> arch/x86/kvm/svm/pmu.c | 2 +-
> arch/x86/kvm/svm/svm.c | 2 +-
> arch/x86/kvm/vmx/pmu_intel.c | 2 +-
> arch/x86/kvm/vmx/vmx.c | 2 +-
> arch/x86/kvm/x86.c | 23 ++++++++++++
> 9 files changed, 94 insertions(+), 42 deletions(-)
> create mode 100644 arch/x86/include/asm/kvm-x86-pmu-ops.h
>

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