Commit 4c41a4b8 authored by Marc Zyngier's avatar Marc Zyngier Committed by Luis Henriques

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

commit 688bc577 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: default avatarMarc Zyngier <marc.zyngier@arm.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent c4118026
...@@ -502,8 +502,7 @@ vcpu .req r0 @ vcpu pointer always in r0 ...@@ -502,8 +502,7 @@ vcpu .req r0 @ vcpu pointer always in r0
mrc p15, 0, r2, c14, c3, 1 @ CNTV_CTL mrc p15, 0, r2, c14, c3, 1 @ CNTV_CTL
str r2, [vcpu, #VCPU_TIMER_CNTV_CTL] str r2, [vcpu, #VCPU_TIMER_CNTV_CTL]
bic r2, #1 @ Clear ENABLE
mcr p15, 0, r2, c14, c3, 1 @ CNTV_CTL
isb isb
mrrc p15, 3, r2, r3, c14 @ CNTV_CVAL mrrc p15, 3, r2, r3, c14 @ CNTV_CVAL
...@@ -516,6 +515,9 @@ vcpu .req r0 @ vcpu pointer always in r0 ...@@ -516,6 +515,9 @@ vcpu .req r0 @ vcpu pointer always in r0
mcrr p15, 4, r2, r2, c14 @ CNTVOFF mcrr p15, 4, r2, r2, c14 @ CNTVOFF
1: 1:
mov r2, #0 @ Clear ENABLE
mcr p15, 0, r2, c14, c3, 1 @ CNTV_CTL
#endif #endif
@ Allow physical timer/counter access for the host @ Allow physical timer/counter access for the host
mrc p15, 4, r2, c14, c1, 0 @ CNTHCTL mrc p15, 4, r2, c14, c1, 0 @ CNTHCTL
......
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