The GICv2 and GICv3 architectures allow an active physical interrupt to be forwarded to a guest, and the guest to indirectly perform the deactivation of the interrupt by performing an EOI on the virtual interrupt (see for example the GICv2 spec, 3.2.1). This allows some substantial performance improvement for level triggered interrupts that otherwise have to be masked/unmasked in VFIO, not to mention the required trap back to KVM when the guest performs an EOI. To enable this, the GICs need to be switched to a different EOImode, where a taken interrupt can be left "active" (which prevents the same interrupt from being taken again), while other interrupts are still being processed normally. We also use the new irq_set_vcpu_affinity hook that was introduced for Intel's "Posted Interrupts" to determine whether or not to perform the deactivation at EOI-time. As all of this only makes sense when the kernel can behave as a hypervisor, we only enable this mode on detecting that the kernel was actually booted in HYP mode, and that the GIC supports this feature. This series is a complete rework of a RFC I sent over a year ago: http://lists.infradead.org/pipermail/linux-arm-kernel/2014-June/266328.html Since then, a lot has been either merged (the irqchip_state) or reworked (my active-timer series: http://www.spinics.net/lists/kvm/msg118768.html), and this implements the last few bits for Eric Auger's series to finally make it into the kernel: https://lkml.org/lkml/2015/7/2/268 https://lkml.org/lkml/2015/7/6/291 With all these patches combined, physical interrupt routing from the kernel into a VM becomes possible. Note that the implementation makes use of the static_key mechanism, which is undergoing an extensive rework in 4.3. I intend to convert this code once both are in mainline. This has been tested on Juno (GICv2) and FastModel (GICv3). A branch is available at: git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git irq/gic-irq-vcpu-affinity-v4 * From v3: - Use separate irq_chip structures, leading to much nicer code (tglx) - Dropped Eric's Tested/Reviewed-by as there is significant changes * From v2: - Another small fix from Eric - Some commit message cleanups * From v1: - Fixes after review from Eric - Got rid of the cascaded GICv2 hack (it was broken anyway) - Folded the LPI deactivation patch (it makes more sense as part of the main one. - Some clarifying comments about the "deactivate on mask" - I haven't retained Eric's Reviewed/Tested-by, as the code as significantly changed on GICv2 Marc Zyngier (4): irqchip: GICv3: Convert to EOImode == 1 irqchip: GICv3: Don't deactivate interrupts forwarded to a guest irqchip: GIC: Convert to EOImode == 1 irqchip: GIC: Don't deactivate interrupts forwarded to a guest drivers/irqchip/irq-gic-v3.c | 70 +++++++++++++++++++++-- drivers/irqchip/irq-gic.c | 111 ++++++++++++++++++++++++++++++++++++- include/linux/irqchip/arm-gic-v3.h | 9 +++ include/linux/irqchip/arm-gic.h | 4 ++ 4 files changed, 188 insertions(+), 6 deletions(-) -- 2.1.4 *** BLURB HERE *** Marc Zyngier (4): irqchip: GICv3: Convert to EOImode == 1 irqchip: GICv3: Don't deactivate interrupts forwarded to a guest irqchip: GIC: Convert to EOImode == 1 irqchip: GIC: Don't deactivate interrupts forwarded to a guest drivers/irqchip/irq-gic-v3.c | 91 +++++++++++++++++++++++++-- drivers/irqchip/irq-gic.c | 124 ++++++++++++++++++++++++++++++++++++- include/linux/irqchip/arm-gic-v3.h | 9 +++ include/linux/irqchip/arm-gic.h | 4 ++ 4 files changed, 219 insertions(+), 9 deletions(-) -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
