On 14.08.2013, at 11:07, Peter Maydell wrote: > On 14 August 2013 09:46, Alexander Graf <ag...@suse.de> wrote: >> So can we access those even when the vcpu hasn't been init'ed yet? If so, >> how about the following flow of things for -cpu host: >> >> - QEMU fetches host target type via ioctl (how will this work for >> big-little?) >> - QEMU fetches ID registers, feature flags, etc via one-reg (or are they >> also available via auxv?), puts them into its internal "this is my cpu type" >> fields for the cpu object / class. >> - QEMU calls VCPU_INIT with the type it fetched via ioctl. > > Curiously enough this is pretty much exactly what this patch > actually does (except we don't bother to actually stash the ID > register values because we know they'll never be used).
Heh, you mean I should read patches after 0/x too? :) You're right, the main difference is that KVM doesn't have any idea what a "host" style CPU is. It only knows how to report to QEMU what the current host CPU would be, so that anything from VCPU_INIT onwards is 100% identical regardless of whether the user said -cpu host or -cpu xxx. I'm still puzzled on how this will work with BIG.little btw. Alex
