This is a note to let you know that I've just added the patch titled arm64: KVM: Disable virtual timer even if the guest is not using it to the 3.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm64-kvm-disable-virtual-timer-even-if-the-guest-is-not-using-it.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From c4cbba9fa078f55d9f6d081dbb4aec7cf969e7c7 Mon Sep 17 00:00:00 2001 From: Marc Zyngier <marc.zyngier@xxxxxxx> Date: Wed, 16 Sep 2015 16:18:59 +0100 Subject: arm64: KVM: Disable virtual timer even if the guest is not using it From: Marc Zyngier <marc.zyngier@xxxxxxx> commit c4cbba9fa078f55d9f6d081dbb4aec7cf969e7c7 upstream. 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. Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/arm64/kvm/hyp.S | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/arch/arm64/kvm/hyp.S +++ b/arch/arm64/kvm/hyp.S @@ -485,8 +485,6 @@ CPU_BE( rev w5, w5 ) 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 @@ -494,6 +492,9 @@ CPU_BE( rev w5, w5 ) str x3, [x0, #VCPU_TIMER_CNTV_CVAL] 1: + // Disable the virtual timer + msr cntv_ctl_el0, xzr + // Allow physical timer/counter access for the host mrs x2, cnthctl_el2 orr x2, x2, #3 Patches currently in stable-queue which might be from marc.zyngier@xxxxxxx are queue-3.14/arm64-head.s-initialise-mdcr_el2-in-el2_setup.patch queue-3.14/arm64-kvm-disable-virtual-timer-even-if-the-guest-is-not-using-it.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html