Date: Fri, 17 Oct 2014 15:24:39 +0000 From: Ashutosh Kumar <mrashutosh@hotmail.com> To: "freebsd-virtualization@freebsd.org" <freebsd-virtualization@freebsd.org> Subject: RE: io-apic interrupt migration on bhyve Message-ID: <SNT150-W7159835C18B15B9E9A6B86DFA80@phx.gbl> In-Reply-To: <SNT150-W7ABD0AAB97FA85DFF5464DFA80@phx.gbl> References: <SNT150-W7ABD0AAB97FA85DFF5464DFA80@phx.gbl>
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Hi, On more analysis I found that there is a race condition in Guest OS such that before complete initialization happens for APs the interrupt migration takes place and hence incorrect cpu is written to io-apic's rte for that particular pin. The debug prints either in Guest OS or vmm just kills this race condition. Thanks. RegardsAshutosh > From: mrashutosh@hotmail.com > To: freebsd-virtualization@freebsd.org > Subject: io-apic interrupt migration on bhyve > Date: Fri, 17 Oct 2014 13:24:34 +0000 > > > > Hi, > > > > I am witnessing some strange behavior w.r.t io-apic > interrupt migration on bhyve. > > I have below assignment for a level triggered > interrupt: > > > > io-apic pin - p > > cpu vector - v > > cpu id - 0 > > > > when this interrupt is migrated to cpu 1 then > the assignment is as below > > > > io-apic pin - p > > cpu vector - v1 > > cpu id - 1 > > > > When VM boots up then OS is getting interrupts for > > > > io-apic pin - p > > cpu vector - v1 > > cpu id - 0 > > > > Added debug prints in vioapic_write function > to check the values written to io-apic rte for this pin and then VM gets > correct interrupts i.e (vector v, cpu 0 ) before the interrupts are migrated and > (vector v1, cpu 1) after the migration When prints are removed then the > problem happens and we see interrupts for (vector v1 and cpu 0). > RegardsAshutosh > _______________________________________________ > freebsd-virtualization@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization > To unsubscribe, send any mail to "freebsd-virtualization-unsubscribe@freebsd.org"
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