On Wed, Jun 25, 2014 at 4:28 AM, Marc Zyngier <marc.zyng...@arm.com> wrote: > So far, GICv2 has been used in with EOImode == 0. The effect of this > mode is to perform the priority drop and the deactivation of the > interrupt at the same time. > > While this works perfectly for Linux (we only have a single priority), > it causes issues when an interrupt is forwarded to a guest, and when > we want the guest to perform the EOI itself. > > For this case, the GIC architecture provides EOImode == 1, where: > - A write to the EOI register drops the priority of the interrupt and leaves > it active. Other interrupts at the same priority level can now be taken, > but the active interrupt cannot be taken again > - A write to the DIR marks the interrupt as inactive, meaning it can > now be taken again. > > We only enable this feature when booted in HYP mode. Also, as most device > trees are broken (they report the CPU interface size to be 4kB, while > the GICv2 CPU interface size is 8kB), output a warning if we're booted > in HYP mode, and disable the feature.
Why not fix-up the size so the feature can be enabled? Rob -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
