linux-kernel - Re: [PATCH 00/18] KVM: x86: Fastpath cleanups and PMU prep work

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Message-ID: <175564464232.3065542.6062884759434886265.b4-ty@google.com>
Date: Tue, 19 Aug 2025 16:11:59 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, Xin Li <xin@...or.com>, 
	Dapeng Mi <dapeng1.mi@...ux.intel.com>, Sandipan Das <sandipan.das@....com>
Subject: Re: [PATCH 00/18] KVM: x86: Fastpath cleanups and PMU prep work

On Tue, 05 Aug 2025 12:05:08 -0700, Sean Christopherson wrote:
> This is a prep series for the mediated PMU, and for Xin's series to add
> support for the immediate forms of RDMSR and WRMSRNS (I'll post a v3 of
> that series on top of this).
> 
> The first half cleans up a variety of warts and flaws in the VM-Exit fastpath
> handlers.  The second half cleans up the PMU code related to "triggering"
> instruction retired and branches retired events.  The end goal of the two
> halves (other than general cleanup) is to be able bail from the fastpath when
> using the mediated PMU and the guest is counting instructions retired, with
> minimal overhead, e.g. without having to acquire SRCU.
> 
> [...]

Applied to kvm-x86 misc, thanks!

[01/18] KVM: SVM: Skip fastpath emulation on VM-Exit if next RIP isn't valid
        https://github.com/kvm-x86/linux/commit/0910dd7c9ad4
[02/18] KVM: x86: Add kvm_icr_to_lapic_irq() helper to allow for fastpath IPIs
        https://github.com/kvm-x86/linux/commit/15daa58e78ce
[03/18] KVM: x86: Only allow "fast" IPIs in fastpath WRMSR(X2APIC_ICR) handler
        https://github.com/kvm-x86/linux/commit/777414340085
[04/18] KVM: x86: Drop semi-arbitrary restrictions on IPI type in fastpath
        https://github.com/kvm-x86/linux/commit/aeeb4c7fff52
[05/18] KVM: x86: Unconditionally handle MSR_IA32_TSC_DEADLINE in fastpath exits
        https://github.com/kvm-x86/linux/commit/0a94b2042419
[06/18] KVM: x86: Acquire SRCU in WRMSR fastpath iff instruction needs to be skipped
        https://github.com/kvm-x86/linux/commit/aebcbb609773
[07/18] KVM: x86: Unconditionally grab data from EDX:EAX in WRMSR fastpath
        https://github.com/kvm-x86/linux/commit/aa2e4f029341
[08/18] KVM: x86: Fold WRMSR fastpath helpers into the main handler
        https://github.com/kvm-x86/linux/commit/d618fb4e43a0
[09/18] KVM: x86/pmu: Move kvm_init_pmu_capability() to pmu.c
        https://github.com/kvm-x86/linux/commit/a3e80bf73ee1
[10/18] KVM: x86/pmu: Add wrappers for counting emulated instructions/branches
        https://github.com/kvm-x86/linux/commit/43f5bea2639c
[11/18] KVM: x86/pmu: Calculate set of to-be-emulated PMCs at time of WRMSRs
        https://github.com/kvm-x86/linux/commit/5dfd498bad5f
[12/18] KVM: x86/pmu: Rename pmc_speculative_in_use() to pmc_is_locally_enabled()
        https://github.com/kvm-x86/linux/commit/6b6f1adc4332
[13/18] KVM: x86/pmu: Open code pmc_event_is_allowed() in its callers
        https://github.com/kvm-x86/linux/commit/e630bb52d27f
[14/18] KVM: x86/pmu: Drop redundant check on PMC being globally enabled for emulation
        https://github.com/kvm-x86/linux/commit/58baa649ea09
[15/18] KVM: x86/pmu: Drop redundant check on PMC being locally enabled for emulation
        https://github.com/kvm-x86/linux/commit/8709656514c1
[16/18] KVM: x86/pmu: Rename check_pmu_event_filter() to pmc_is_event_allowed()
        https://github.com/kvm-x86/linux/commit/3eced8b07bb9
[17/18] KVM: x86: Push acquisition of SRCU in fastpath into kvm_pmu_trigger_event()
        https://github.com/kvm-x86/linux/commit/8bb8b60c95c5
[18/18] KVM: x86: Add a fastpath handler for INVD
        https://github.com/kvm-x86/linux/commit/6c3d4b917995

--
https://github.com/kvm-x86/linux/tree/next