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Thu, 27 Aug 2026 06:31:33 -0700 (PDT) Message-ID: <41e1eee3-2cbd-46e9-9bce-5246244c5d12@gmail.com> Date: Thu, 27 Aug 2026 14:31:31 +0100 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: jthoughton@google.com Cc: bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, kernel-patches@amazon.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, mamarang@amazon.com, mancio@amazon.co.uk, mingo@redhat.com, pbonzini@redhat.com, seanjc@google.com, tglx@kernel.org, x86@kernel.org, zoumboul@amazon.com References: Subject: Re: [RFC] KVM: x86/mmu: Prefetch forward run of pages on TDP page faults Content-Language: en-US From: "Thomson, Jack" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On Tue, Aug 25, 2026, James Houghton wrote: > Firecracker might be using async PF; using KVM Userfault basically > disables async PF. I've been working on exactly this series [1] on top of your KVM Userfault series that turns userfault exits into async PFs, with userspace signalling completion either via ioctl or this idea of an exitless variant which skips the KVM_RUN round-trip per fault which has some exciting numbers! It's running in our CI at the moment, and hoping to publish this as an RFC soon :) [1]: https://github.com/firecracker-microvm/firecracker/tree/feature/secret-hiding/resources/hiding_ci/kernels/6.18-secret-hiding/linux_patches/60-async-pf -- Thanks, Jack