[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3] xen/arm: introduce PLATFORM_QUIRK_GUEST_PIRQ_NEED_EOI
On Wed, Jul 9, 2014 at 8:41 PM, Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> wrote: > On Wed, 9 Jul 2014, Julien Grall wrote: >> On 07/09/2014 03:40 PM, Ian Campbell wrote: >> >> I think we should check GIC Dist address passed in DTS by >> >> u-boot to Xen. If GIC Dist address is secured address then >> >> enable the quirk otherwise disable the qurik. >> > >> > Isn't IGROUPR readable from NS? In which case we should be able to spot >> > the difference, I think? > > Anup, can you confirm that we can use IGROUPR to spot the difference? > Otherwise is there another register we can use? Yes, IGROUPR of the secured GIC registers would be correct register to spot the difference. More precisely, if IGROUPR0 == 0xFFFFFFFF in GIC secured registers then don't use the quirk for X-Gene. > > In any case given that only you can test it, I think that it should be > one of you guys that come up with a way to detect the change and submit > a patch to conditionally disable the workaround. Sure, most likely Pranav will send a patch for Xen once APM releases updated u-boot binary. Thanks, Anup > > >> > Stefano, you might want to arrange in your patch to cache the value of >> > the quirk in the gicv2 struct -- otherwise all the calls to >> > platform_has_quirk are going to add up. >> >> Can't we cache the value in the platform code? I don't think it's too >> expensive to call the platform_has_quirk in this case. > > Caching the value in gic-v2.c seems a bit overkill. But we could turn > platform->quirks() into a bitfield, then we can significantly reduce > memory accesses when checking for quirks, from 3 to just 1. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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