[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [Draft F] Xen on ARM vITS Handling
On Fri, 2015-06-12 at 10:05 -0400, Julien Grall wrote: > > On 12/06/2015 09:32, Julien Grall wrote: > > > > > > On 12/06/2015 09:16, Ian Campbell wrote: > >> On Fri, 2015-06-12 at 09:09 -0400, Julien Grall wrote: > >>> Hi Ian, > >>> > >>> On 12/06/2015 04:52, Ian Campbell wrote: > >>>> On Fri, 2015-06-12 at 14:07 +0530, Vijay Kilari wrote: > >>>> So pLPIs must be routed at device assignment time because in the vLPI > >>>> configuration table trap there is no mapping back to a single pLPI. > >>> > >>> I just remembered the exact reason that made use to differ SPI enabling. > >> > >> I can't parse this sentence, differ how? > > > > deferring sorry. > > > >> > >>> When the device is assigned, the domain VCPUs are still down (even > >>> VCPU0). > >>> > >>> If we receive an interrupt before the VCPU0 is unpaused, the interrupt > >>> will be lost. Same if the interrupt is not yet configured (i.e before > >>> the vITS setup correctly the table) with your proposal. > >> > >> Is this any different to booting with the ITT not setup? > > > > I don't understand your question. > > > >> (SPIs are a slightly different case because they don't need h/w routing) > > > > I think you mixed PPIs with SPIs. SPIs (shared private interrupt) > > s/private/processor/ It's "peripheral" ;-) > > > requires h/w routing. > > > >> > >>> This could happen when the device is not quiescent. We had this issue on > >>> the vexpress at boot time when the network card was trying to send an > >>> interrupt before DOM0 is setup. > >> > >> I don't fully understand the issue you are trying to describe, but do > >> you want to propose a change to the spec? > > > > I actually don't know how to modify it. So it's an open question. > > > > vgic_vcpu_inject_irq doesn't queue the interrupt if a VCPU is down. I > > think this is because the state of the VCPU wouldn't be correct. > > > > The process would be something like: > > > > - Creation of the domain > > => All vCPUs are down > > > > - Device is assigned to the guest > > => Enable physical LPIs > > > > * physical LPI is received * > > => Will be ignored and not EOIed (VCPU0 is down) > > => The LPI will never fired again during the guest life > > > > - Domain is started by the toolstack > > => VCPU0 is online > > > > Regards, > > > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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