Messages in this thread | | | Date | Fri, 22 Oct 2021 12:12:35 +0200 | Subject | Re: [PATCH v2 0/4] KVM: x86: APICv cleanups | From | Paolo Bonzini <> |
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On 22/10/21 02:49, Sean Christopherson wrote: > APICv cleanups and a dissertation on handling concurrent APIC access page > faults and APICv inhibit updates. > > I've tested this but haven't hammered the AVIC stuff, I'd appreciate it if > someone with the Hyper-V setup can beat on the AVIC toggling. > > Sean Christopherson (4): > KVM: x86/mmu: Use vCPU's APICv status when handling APIC_ACCESS > memslot > KVM: x86: Move SVM's APICv sanity check to common x86 > KVM: x86: Move apicv_active flag from vCPU to in-kernel local APIC > KVM: x86: Use rw_semaphore for APICv lock to allow vCPU parallelism > > arch/x86/include/asm/kvm_host.h | 3 +- > arch/x86/kvm/hyperv.c | 4 +-- > arch/x86/kvm/lapic.c | 46 ++++++++++--------------- > arch/x86/kvm/lapic.h | 5 +-- > arch/x86/kvm/mmu/mmu.c | 29 ++++++++++++++-- > arch/x86/kvm/svm/avic.c | 2 +- > arch/x86/kvm/svm/svm.c | 2 -- > arch/x86/kvm/vmx/vmx.c | 4 +-- > arch/x86/kvm/x86.c | 59 ++++++++++++++++++++++----------- > 9 files changed, 93 insertions(+), 61 deletions(-) >
Queued, thanks. I only made small edits to the comment in patch 1, to make it very slightly shorter.
* 2a. APICv is globally disabled but locally enabled, and this * vCPU acquires mmu_lock before __kvm_request_apicv_update * calls kvm_zap_gfn_range(). This vCPU will install a stale * SPTE, but no one will consume it as (a) no vCPUs can be * running due to the kick from KVM_REQ_APICV_UPDATE, and * (b) because KVM_REQ_APICV_UPDATE is raised before the VM * state is update, vCPUs attempting to service the request * will block on apicv_update_lock. The update flow will * then zap the SPTE and release the lock.
Paolo
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