Messages in this thread |  | | Subject | Re: [PATCH 34/35] x86/kvm: Add IBPB support | From | David Woodhouse <> | Date | Fri, 19 Jan 2018 17:08:13 +0100 |
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On Fri, 2018-01-19 at 16:25 +0100, Paolo Bonzini wrote: > Without retpolines, KVM userspace is not protected from the guest > poisoning the BTB, because there is no IBRS-barrier on the vmexit > path. > So there are two more IBPBs that are needed if retpolines are > enabled: > > 1) in kvm_sched_out > > 2) at the end of vcpu_run
Hm, yes. That does seem reasonable. Can we make it conditional so it only happens *if* we end up back in userspace, and not for a VM- >kernel->VM transition?
And can I have a patch against http://git.infradead.org/users/dwmw2/linux-retpoline.git/shortlog/refs/heads/ibpb-upstream please (see the XX in that top commit too).
I'm still putting that together, and the IBRS bits on top; getting on an airplane to spend some more quality time with it now... [unhandled content-type:application/x-pkcs7-signature] |  |