From: Andrew Jones Date: Mon, 27 May 2019 11:46:19 +0000 (+0200) Subject: KVM: arm/arm64: Fix emulated ptimer irq injection X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e4e5a865e9a9e8e47ac1959b629e9f3ae3b062f2;p=linux.git KVM: arm/arm64: Fix emulated ptimer irq injection The emulated ptimer needs to track the level changes, otherwise the the interrupt will never get deasserted, resulting in the guest getting stuck in an interrupt storm if it enables ptimer interrupts. This was found with kvm-unit-tests; the ptimer tests hung as soon as interrupts were enabled. Typical Linux guests don't have a problem as they prefer using the virtual timer. Fixes: bee038a674875 ("KVM: arm/arm64: Rework the timer code to use a timer_map") Signed-off-by: Andrew Jones [Simplified the patch to res we only care about emulated timers here] Signed-off-by: Marc Zyngier --- diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index 7fc272ecae162..1b1c449ceaf4f 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -321,14 +321,15 @@ static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level, } } +/* Only called for a fully emulated timer */ static void timer_emulate(struct arch_timer_context *ctx) { bool should_fire = kvm_timer_should_fire(ctx); trace_kvm_timer_emulate(ctx, should_fire); - if (should_fire) { - kvm_timer_update_irq(ctx->vcpu, true, ctx); + if (should_fire != ctx->irq.level) { + kvm_timer_update_irq(ctx->vcpu, should_fire, ctx); return; }