Re: [PATCH v2] KVM: x86: Remove support for reporting coalesced APIC IRQs
On Mon, May 13, 2013 at 10:30:33PM -0300, Marcelo Tosatti wrote: > On Thu, May 02, 2013 at 10:14:32PM -0300, Marcelo Tosatti wrote: > > On Sun, Apr 28, 2013 at 02:00:41PM +0200, Jan Kiszka wrote: > > > From: Jan Kiszka > > > > > > Since the arrival of posted interrupt support we can no longer guarantee > > > that coalesced IRQs are always reported to the IRQ source. Moreover, > > > accumulated APIC timer events could cause a busy loop when a VCPU should > > > rather be halted. The consensus is to remove coalesced tracking from the > > > LAPIC. > > > > > > Signed-off-by: Jan Kiszka > > > --- > > > > > > Changes in v2: > > > - preserve return values where we need to count to how many VCPUs an > > >IRQ was delivered > > > > It would be best to confirm first that no guest depends on LAPIC timer > > reinjection (rather than wait for guests to break and spend time > > debugging). Specially since such kind of bugs are not easy to pinpoint. > > Or if there is evidence to invalidate such reasoning, please point it > > out. > > > > Honestly i don't recall: would have to check RHEL5.32 UP/SMP, RHEL5.64 > > UP/SMP, RHEL4.32, RHEL4.64, RHEL6. Can do that in a week or so. > > Its OK to remove LAPIC timer reinjection. Applied. Thanks for checking! -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2] KVM: x86: Remove support for reporting coalesced APIC IRQs
On Thu, May 02, 2013 at 10:14:32PM -0300, Marcelo Tosatti wrote: > On Sun, Apr 28, 2013 at 02:00:41PM +0200, Jan Kiszka wrote: > > From: Jan Kiszka > > > > Since the arrival of posted interrupt support we can no longer guarantee > > that coalesced IRQs are always reported to the IRQ source. Moreover, > > accumulated APIC timer events could cause a busy loop when a VCPU should > > rather be halted. The consensus is to remove coalesced tracking from the > > LAPIC. > > > > Signed-off-by: Jan Kiszka > > --- > > > > Changes in v2: > > - preserve return values where we need to count to how many VCPUs an > >IRQ was delivered > > It would be best to confirm first that no guest depends on LAPIC timer > reinjection (rather than wait for guests to break and spend time > debugging). Specially since such kind of bugs are not easy to pinpoint. > Or if there is evidence to invalidate such reasoning, please point it > out. > > Honestly i don't recall: would have to check RHEL5.32 UP/SMP, RHEL5.64 > UP/SMP, RHEL4.32, RHEL4.64, RHEL6. Can do that in a week or so. Its OK to remove LAPIC timer reinjection. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2] KVM: x86: Remove support for reporting coalesced APIC IRQs
On Sun, Apr 28, 2013 at 02:00:41PM +0200, Jan Kiszka wrote: > From: Jan Kiszka > > Since the arrival of posted interrupt support we can no longer guarantee > that coalesced IRQs are always reported to the IRQ source. Moreover, > accumulated APIC timer events could cause a busy loop when a VCPU should > rather be halted. The consensus is to remove coalesced tracking from the > LAPIC. > > Signed-off-by: Jan Kiszka > --- > > Changes in v2: > - preserve return values where we need to count to how many VCPUs an >IRQ was delivered It would be best to confirm first that no guest depends on LAPIC timer reinjection (rather than wait for guests to break and spend time debugging). Specially since such kind of bugs are not easy to pinpoint. Or if there is evidence to invalidate such reasoning, please point it out. Honestly i don't recall: would have to check RHEL5.32 UP/SMP, RHEL5.64 UP/SMP, RHEL4.32, RHEL4.64, RHEL6. Can do that in a week or so. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
