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ARM: KVM: arch_timers: zero CNTVOFF upon return to host

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To use the virtual counters from the host, we need to ensure that
CNTVOFF doesn't change unexpectedly. When we change to a guest, we
replace the host's CNTVOFF, but we don't restore it when returning to
the host.

As the host sets CNTVOFF to zero, and never changes it, we can simply
zero CNTVOFF when returning to the host. This patch adds said zeroing to
the return to host path.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Christoffer Dall <cdall@cs.columbia.edu>
This commit is contained in:
Mark Rutland 2013-03-26 13:41:35 +00:00
parent 0af0b189ab
commit f793c23ebb
1 changed files with 4 additions and 0 deletions
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4
arch/arm/kvm/interrupts_head.S
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@ -497,6 +497,10 @@ vcpu .req r0 @ vcpu pointer always in r0
add r5, vcpu, r4
strd r2, r3, [r5]
@ Ensure host CNTVCT == CNTPCT
mov r2, #0
mcrr p15, 4, r2, r2, c14 @ CNTVOFF
1:
#endif
@ Allow physical timer/counter access for the host