Messages in this thread |  | | From | Andy Lutomirski <> | Date | Fri, 19 Jan 2018 08:27:04 -0800 | Subject | Re: [PATCH 34/35] x86/kvm: Add IBPB support |
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On Fri, Jan 19, 2018 at 8:08 AM, David Woodhouse <dwmw2@infradead.org> wrote: > 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?
kvm_on_user_return(), perhaps?
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