From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Wed, 16 Sep 2015 16:58:06 +0100 Subject: [PATCH 2/3] arm64: KVM: Disable virtual timer even if the guest is not using it In-Reply-To: <1442419087-24648-1-git-send-email-marc.zyngier@arm.com> References: <1442419087-24648-1-git-send-email-marc.zyngier@arm.com> Message-ID: <1442419087-24648-3-git-send-email-marc.zyngier@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org When running a guest with the architected timer disabled (with QEMU and the kernel_irqchip=off option, for example), it is important to make sure the timer gets turned off. Otherwise, the guest may try to enable it anyway, leading to a screaming HW interrupt. The fix is to unconditionally turn off the virtual timer on guest exit. Cc: stable at vger.kernel.org Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S index 6addf97..38f5434 100644 --- a/arch/arm64/kvm/hyp.S +++ b/arch/arm64/kvm/hyp.S @@ -570,8 +570,6 @@ alternative_endif mrs x3, cntv_ctl_el0 and x3, x3, #3 str w3, [x0, #VCPU_TIMER_CNTV_CTL] - bic x3, x3, #1 // Clear Enable - msr cntv_ctl_el0, x3 isb @@ -579,6 +577,8 @@ alternative_endif str x3, [x0, #VCPU_TIMER_CNTV_CVAL] 1: + msr cntv_ctl_el0, xzr + // Allow physical timer/counter access for the host mrs x2, cnthctl_el2 orr x2, x2, #3 -- 2.1.4