On Wed, Jul 08, 2020 at 04:32:51PM +0100, Peter Maydell wrote: > On Wed, 8 Jul 2020 at 16:25, Eduardo Habkost <ehabk...@redhat.com> wrote: > > On Wed, Jul 08, 2020 at 02:14:03PM +0100, Peter Maydell wrote: > > > The original bug as described in the commit message sounds > > > to me like something we should look to fix in the implementation > > > of async_run_on_cpu() -- it shouldn't cause a CPU that's halfway > > > through reset to do a KVM_RUN or otherwise run guest code, > > > whether that CPU is going to start powered-up or powered-down. > > > > What "halfway through reset" means, exactly? Isn't halted==1 > > enough to indicate the CPU is in that state? > > I mean "while we're in the middle of the CPU method that's > called by cpu_reset()". "halted==1" says "the CPU is halted"; > that's not the same thing. KVM_RUN happening > as a side effect in the middle of that code is a bug > whether the CPU happens to be intended to be put into the > halted state or not. If the CPU is intended to be created > not-halted then KVM_RUN can happen after cpu reset > completes, but not before.
Wait, I thought we already had mechanisms to prevent that from happening. Otherwise, it would never be safe for cpu_reset() to touch the CPU registers. -- Eduardo
