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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id d5sm12773936edu.12.2021.02.22.10.17.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 22 Feb 2021 10:17:07 -0800 (PST) Subject: Re: [PATCH v4 0/2] KVM: x86/mmu: Skip mmu_notifier changes when possible To: David Stevens , Sean Christopherson Cc: Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Marc Zyngier , James Morse , Julien Thierry , Suzuki K Poulose , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, Huacai Chen , Aleksandar Markovic , linux-mips@vger.kernel.org, Paul Mackerras , kvm-ppc@vger.kernel.org, Christian Borntraeger , Janosch Frank , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , David Stevens References: <20210222024522.1751719-1-stevensd@google.com> From: Paolo Bonzini Message-ID: <7fe10f74-e183-411a-468b-93fcdf786bb6@redhat.com> Date: Mon, 22 Feb 2021 19:17:06 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <20210222024522.1751719-1-stevensd@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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