From: Christoffer Dall Date: Thu, 14 Dec 2017 23:30:12 +0000 (+0100) Subject: KVM: arm/arm64: Fix timer enable flow X-Git-Tag: v4.19~1811^2~3^2~3 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0eb7c33cadf6b2f1a94e58ded8b0eb89b4eba382;p=platform%2Fkernel%2Flinux-rpi.git KVM: arm/arm64: Fix timer enable flow When enabling the timer on the first run, we fail to ever restore the state and mark it as loaded. That means, that in the initial entry to the VCPU ioctl, unless we exit to userspace for some reason such as a pending signal, if the guest programs a timer and blocks, we will wait forever, because we never read back the hardware state (the loaded flag is not set), and so we think the timer is disabled, and we never schedule a background soft timer. The end result? The VCPU blocks forever, and the only solution is to kill the thread. Fixes: 4a2c4da1250d ("arm/arm64: KVM: Load the timer state when enabling the timer") Reported-by: Marc Zyngier Reviewed-by: Marc Zyngier Tested-by: Marc Zyngier Signed-off-by: Christoffer Dall --- diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index 14c018f..cc29a81 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -846,10 +846,7 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu) no_vgic: preempt_disable(); timer->enabled = 1; - if (!irqchip_in_kernel(vcpu->kvm)) - kvm_timer_vcpu_load_user(vcpu); - else - kvm_timer_vcpu_load_vgic(vcpu); + kvm_timer_vcpu_load(vcpu); preempt_enable(); return 0;