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arm64: KVM: Disable virtual timer even if the guest is not using it

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commit c4cbba9fa0 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Marc Zyngier
2015-09-16 16:18:59 +01:00
committed by Greg Kroah-Hartman
parent 7dd1e0b3f2
commit f283a20ab7
1 changed files with 3 additions and 2 deletions
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5
arch/arm64/kvm/hyp.S
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@@ -844,8 +844,6 @@
mrs x3, cntv_ctl_el0 mrs x3, cntv_ctl_el0
and x3, x3, #3 and x3, x3, #3
str w3, [x0, #VCPU_TIMER_CNTV_CTL] str w3, [x0, #VCPU_TIMER_CNTV_CTL]
bic x3, x3, #1 // Clear Enable
msr cntv_ctl_el0, x3
isb isb
@@ -853,6 +851,9 @@
str x3, [x0, #VCPU_TIMER_CNTV_CVAL] str x3, [x0, #VCPU_TIMER_CNTV_CVAL]
1: 1:
// Disable the virtual timer
msr cntv_ctl_el0, xzr
// Allow physical timer/counter access for the host // Allow physical timer/counter access for the host
mrs x2, cnthctl_el2 mrs x2, cnthctl_el2
orr x2, x2, #3 orr x2, x2, #3