Re: [PATCH v4 3/9] KVM: arm64: vgic: Be tolerant to the lack of maintenance interrupt masking

Hi Marc,

On 6/11/21 5:38 PM, Alexandru Elisei wrote:

Hi Marc,

On 6/1/21 11:39 AM, Marc Zyngier wrote:

quoted

As it turns out, not all the interrupt controllers are able to
expose a vGIC maintenance interrupt that can be independently
enabled/disabled.

And to be fair, it doesn't really matter as all we require is
for the interrupt to kick us out of guest mode out way or another.

To that effect, add gic_kvm_info.no_maint_irq_mask for an interrupt
controller to advertise the lack of masking.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic/vgic-init.c       | 8 +++++++-
 include/linux/irqchip/arm-vgic-info.h | 2 ++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index 2fdb65529594..6752d084934d 100644
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c

@@ -519,12 +519,15 @@ void kvm_vgic_init_cpu_hardware(void)
  */
 int kvm_vgic_hyp_init(void)
 {
+	bool has_mask;
 	int ret;
 
 	if (!gic_kvm_info)
 		return -ENODEV;
 
-	if (!gic_kvm_info->maint_irq) {
+	has_mask = !gic_kvm_info->no_maint_irq_mask;

This double negative is pretty awkward, I suppose this was done to avoid changes
to the gic drivers, because the default value is 0 (false). Just an idea, maybe
renaming it to maint_irq_unmaskable would be more readable?

Actually, after another look, the current name stopped looking awkward to me.

Thanks,

Alex


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