On 07/01/2015 08:18, Andy Lutomirski wrote: >>> >> Thus far, I've been told unambiguously that a guest can't observe pvti >>> >> while it's being written, and I think you're now telling me that this >>> >> isn't true and that a guest *can* observe pvti while it's being >>> >> written while the low bit of the version field is not set. If so, >>> >> this is rather strongly incompatible with the spec in the KVM docs. >> > >> > Where am I saying that? > I thought the conclusion from what you and Marcelo pointed out about > the code was that, once the first vCPU updated its pvti, it could > start running guest code while the other vCPUs are still updating > pvti, so its guest code can observe the other vCPUs mid-update. Ah, in that sense you're right. However, each VCPU cannot observe _its own_ pvti entry while it's being written (no matter what's in the low bit of the version field). Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
