On 25/10/18 13:51, Jan Beulich wrote: >>>> On 15.10.18 at 14:06, <andrew.coop...@citrix.com> wrote: >> From the debugging, we see that PPR/IRR/ISR appear to retain their state >> across the mwait, and there is nothing in the manual which I can see >> discussing the interaction of LAPIC state and C states. > Is it perhaps a bad idea to go idle with an un-acked interrupt?
Most likely. Then again, going idle with an un-acked line interrupt does appear to work. It is only un-acked edge interrupts which appear to hit this issue. Still - I'd prefer some guidance from the hardware folk as to what can realistically be expected here. > Quite possibly that's not something an ordinary OS would do. This is definitely not something an ordinary OS would do during normal operation. Xen suffers more than most other hypervisors because our device drivers are in dom0. That said, can't we just mask the line at the PIC/IO-APIC and forgo the PEOI stack entirely? The more I think about how our interrupt handling works, the more I think vastly over complicated. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
