| From | Luis Henriques <> | Subject | [PATCH 3.16.y-ckt 017/104] arm: KVM: Disable virtual timer even if the guest is not using it | Date | Mon, 26 Oct 2015 13:41:59 +0000 |
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3.16.7-ckt19 -stable review patch. If anyone has any objections, please let me know.
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From: Marc Zyngier <marc.zyngier@arm.com>
commit 688bc577ac42ae3d07c889a1f0a72f0b23763d58 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.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> [ luis: backported to 3.16: adjusted context ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- arch/arm/kvm/interrupts_head.S | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S index 2973b2d342fa..cb1d567ada5e 100644 --- a/arch/arm/kvm/interrupts_head.S +++ b/arch/arm/kvm/interrupts_head.S @@ -502,8 +502,7 @@ vcpu .req r0 @ vcpu pointer always in r0 mrc p15, 0, r2, c14, c3, 1 @ CNTV_CTL str r2, [vcpu, #VCPU_TIMER_CNTV_CTL] - bic r2, #1 @ Clear ENABLE - mcr p15, 0, r2, c14, c3, 1 @ CNTV_CTL + isb mrrc p15, 3, r2, r3, c14 @ CNTV_CVAL @@ -516,6 +515,9 @@ vcpu .req r0 @ vcpu pointer always in r0 mcrr p15, 4, r2, r2, c14 @ CNTVOFF 1: + mov r2, #0 @ Clear ENABLE + mcr p15, 0, r2, c14, c3, 1 @ CNTV_CTL + #endif @ Allow physical timer/counter access for the host mrc p15, 4, r2, c14, c1, 0 @ CNTHCTL
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