From 488f94d7212b00a2ec72fb886b155f1b04c5aa98 Mon Sep 17 00:00:00 2001 From: Jintack Lim Date: Thu, 1 Dec 2016 14:32:05 -0500 Subject: KVM: arm64: Access CNTHCTL_EL2 bit fields correctly on VHE systems Current KVM world switch code is unintentionally setting wrong bits to CNTHCTL_EL2 when E2H == 1, which may allow guest OS to access physical timer. Bit positions of CNTHCTL_EL2 are changing depending on HCR_EL2.E2H bit. EL1PCEN and EL1PCTEN are 1st and 0th bits when E2H is not set, but they are 11th and 10th bits respectively when E2H is set. In fact, on VHE we only need to set those bits once, not for every world switch. This is because the host kernel runs in EL2 with HCR_EL2.TGE == 1, which makes those bits have no effect for the host kernel execution. So we just set those bits once for guests, and that's it. Signed-off-by: Jintack Lim Reviewed-by: Marc Zyngier Signed-off-by: Marc Zyngier --- include/kvm/arm_arch_timer.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/kvm/arm_arch_timer.h') diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h index b717ed9d2b75..5c970ce67949 100644 --- a/include/kvm/arm_arch_timer.h +++ b/include/kvm/arm_arch_timer.h @@ -76,4 +76,5 @@ void kvm_timer_unschedule(struct kvm_vcpu *vcpu); void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu); +void kvm_timer_init_vhe(void); #endif -- cgit v1.2.3