On 12/09/2016 19:37, Christian Borntraeger wrote: > On 09/12/2016 06:44 PM, Paolo Bonzini wrote: > > I think that two CPUs doing reciprocal SIGPs could in principle end up > > waiting on each other to complete their run_on_cpu. If the SIGP has to > > be synchronous the fix is not trivial (you'd have to put the CPU in a > > state similar to cpu->halted = 1), otherwise it's enough to replace > > run_on_cpu with async_run_on_cpu. > > IIRC the sigps are supossed to be serialized by the big QEMU lock. WIll > have a look.
Yes, but run_on_cpu drops it when it waits on the qemu_work_cond condition variable. (Related: I stumbled upon it because I wanted to remove the BQL from run_on_cpu work items). Paolo
