| From | Kamal Mostafa <> | Subject | [PATCH 3.19.y-ckt 39/86] arm64: KVM: Disable virtual timer even if the guest is not using it | Date | Tue, 27 Oct 2015 14:29:39 -0700 |
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3.19.8-ckt9 -stable review patch. If anyone has any objections, please let me know.
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From: Marc Zyngier <marc.zyngier@arm.com>
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@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/arm64/kvm/hyp.S | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S index cbaa8bc..0a2ff0f 100644 --- a/arch/arm64/kvm/hyp.S +++ b/arch/arm64/kvm/hyp.S @@ -843,8 +843,6 @@ 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 @@ -852,6 +850,9 @@ 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 -- 1.9.1
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