Re: [RFC] KVM: x86/mmu: Prefetch forward run of pages on TDP page faults

[Thomson, Jack]

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