On Mon, Oct 09, 2017 at 05:47:18PM +0100, Marc Zyngier wrote: > On 23/09/17 01:41, Christoffer Dall wrote: > > Some systems without proper firmware and/or hardware description data > > don't support the split EOI and deactivate operation. > > > > On such systems, we cannot leave the physical interrupt active after the > > timer handler on the host has run, so we cannot support KVM with an > > in-kernel GIC with the timer changes we are about to introduce. > > > > This patch makes sure that trying to initialize the KVM GIC code will > > fail on such systems. > > > > Cc: Marc Zyngier <marc.zyngier@xxxxxxx> > > Signed-off-by: Christoffer Dall <cdall@xxxxxxxxxx> > > --- > > drivers/irqchip/irq-gic.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c > > index f641e8e..ab12bf4 100644 > > --- a/drivers/irqchip/irq-gic.c > > +++ b/drivers/irqchip/irq-gic.c > > @@ -1420,7 +1420,8 @@ static void __init gic_of_setup_kvm_info(struct device_node *node) > > if (ret) > > return; > > > > - gic_set_kvm_info(&gic_v2_kvm_info); > > + if (static_key_true(&supports_deactivate)) > > + gic_set_kvm_info(&gic_v2_kvm_info); > > } > > > > int __init > > > > Should we add the same level of checking on the ACPI path, just for the > sake symmetry? Yes, we should, if anyone is crazy enough to use ACPI :) > > Also, do we need to add the same thing for GICv3? > Why would split EOI/deactivate not be available on GICv3, actually? It looks like this is not supported unless you have EL2, but I can't seem to find anything in the spec for this, and KVM should support EOI/deactivate for GICv3 guests I think. Am I missing something? Assuming I'm wrong about GICv3, which I probably am, how does this look (on top of the posted patch): diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index 519149e..aed524c 100644 --- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -1228,7 +1228,9 @@ static int __init gic_of_init(struct device_node *node, struct device_node *pare goto out_unmap_rdist; gic_populate_ppi_partitions(node); - gic_of_setup_kvm_info(node); + + if (static_key_true(&supports_deactivate)) + gic_of_setup_kvm_info(node); return 0; out_unmap_rdist: @@ -1517,7 +1519,9 @@ gic_acpi_init(struct acpi_subtable_header *header, const unsigned long end) goto out_fwhandle_free; acpi_set_irq_model(ACPI_IRQ_MODEL_GIC, domain_handle); - gic_acpi_setup_kvm_info(); + + if (static_key_true(&supports_deactivate)) + gic_acpi_setup_kvm_info(); return 0; diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c index ab12bf4..121af5c 100644 --- a/drivers/irqchip/irq-gic.c +++ b/drivers/irqchip/irq-gic.c @@ -1653,7 +1653,8 @@ static int __init gic_v2_acpi_init(struct acpi_subtable_header *header, if (IS_ENABLED(CONFIG_ARM_GIC_V2M)) gicv2m_init(NULL, gic_data[0].domain); - gic_acpi_setup_kvm_info(); + if (static_key_true(&supports_deactivate)) + gic_acpi_setup_kvm_info(); return 0; } Thanks, -Christoffer
