Re: [PATCH v4 0/2] KVM: x86/mmu: Skip mmu_notifier changes when possible

[Paolo Bonzini]

On 22/02/21 03:45, David Stevens wrote:
> These patches reduce how often mmu_notifier updates block guest page
> faults. The primary benefit of this is the reduction in the likelihood
> of extreme latency when handling a page fault due to another thread
> having been preempted while modifying host virtual addresses.
>
> v3 -> v4:
>   - Fix bug by skipping prefetch during invalidation
>
> v2 -> v3:
>   - Added patch to skip check for MMIO page faults
>   - Style changes
>
> David Stevens (1):
>    KVM: x86/mmu: Consider the hva in mmu_notifier retry
>
> Sean Christopherson (1):
>    KVM: x86/mmu: Skip mmu_notifier check when handling MMIO page fault
>
>   arch/powerpc/kvm/book3s_64_mmu_hv.c    |  2 +-
>   arch/powerpc/kvm/book3s_64_mmu_radix.c |  2 +-
>   arch/x86/kvm/mmu/mmu.c                 | 23 ++++++++++++++------
>   arch/x86/kvm/mmu/paging_tmpl.h         |  7 ++++---
>   include/linux/kvm_host.h               | 25 +++++++++++++++++++++-
>   virt/kvm/kvm_main.c                    | 29 ++++++++++++++++++++++----
>   6 files changed, 72 insertions(+), 16 deletions(-)

Rebased, and queued with the fix that Sean suggested.

Paolo