From 4ad9e16af36bbe8657aabe494ff912acbc213ce4 Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Fri, 4 Sep 2015 16:24:39 +0200 Subject: [PATCH] arm/arm64: KVM: arch timer: Reset CNTV_CTL to 0 Provide a better quality of implementation and be architecture compliant on ARMv7 for the architected timer by resetting the CNTV_CTL to 0 on reset of the timer. This change alone fixes the UEFI reset issue reported by Laszlo back in February. Cc: Laszlo Ersek Cc: Ard Biesheuvel Cc: Drew Jones Cc: Wei Huang Cc: Peter Maydell Reviewed-by: Marc Zyngier Signed-off-by: Christoffer Dall Signed-off-by: Marc Zyngier --- virt/kvm/arm/arch_timer.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index 76e38d231e99..48c6e1ac6827 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -199,6 +199,14 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu, */ timer->irq = irq; + /* + * The bits in CNTV_CTL are architecturally reset to UNKNOWN for ARMv8 + * and to 0 for ARMv7. We provide an implementation that always + * resets the timer to be disabled and unmasked and is compliant with + * the ARMv7 architecture. + */ + timer->cntv_ctl = 0; + /* * Tell the VGIC that the virtual interrupt is tied to a * physical interrupt. We do that once per VCPU. -- 2.20.1