[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v4 07/10] xen/arm: call gic_clear_lrs on entry to the hypervisor
On Fri, 2014-03-21 at 16:34 +0000, Stefano Stabellini wrote: > On Fri, 21 Mar 2014, Ian Campbell wrote: > > On Wed, 2014-03-19 at 12:32 +0000, Stefano Stabellini wrote: > > > > Can this not be folded back into the patch which added this function? > > Yes, it can. > > > > > This change is needed by other patches later on. It is going to make > > > sure that the calculation in Xen of the highest priority interrupt > > > currently inflight is correct and accurate and not based on stale data. > > > > Hrm, can we not do this on demand just at the point where we are about > > to make such a calculation? There are going to be lots of hypervisor > > entries which don't want to do anything at all with interrupts, aren't > > there? > > The alternative would be calling gic_clear_lrs at the beginning of > gic_inject and gic_events_need_delivery, that is called by > local_events_need_delivery*. It could be called multiple times before > returning to guest. We could probably invent some sort of "once per h/v entry" construct, but ick. What I was actually thinking of though was to do it even further up -- e.g. in the function which makes the interrupt pending in the first place. I suppose that is called too infrequently though in the absence of maintenance interrupts. > > However gic_clear_lrs only iterates over the LRs in lr_mask, so even > calling it multiple times shouldn't cause more work, the only slow down > would be due to the spin_lock. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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