This is a note to let you know that I've just added the patch titled
ARM: KVM: arch_timers: zero CNTVOFF upon return to host
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-kvm-arch_timers-zero-cntvoff-upon-return-to-host.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f793c23ebbe5afd1cabf4a42a3a297022213756f Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@xxxxxxx>
Date: Tue, 26 Mar 2013 13:41:35 +0000
Subject: ARM: KVM: arch_timers: zero CNTVOFF upon return to host
From: Mark Rutland <mark.rutland@xxxxxxx>
commit f793c23ebbe5afd1cabf4a42a3a297022213756f upstream.
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@xxxxxxx>
Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Acked-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
Acked-by: Christoffer Dall <cdall@xxxxxxxxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/kvm/interrupts_head.S | 4 ++++
1 file changed, 4 insertions(+)
--- a/arch/arm/kvm/interrupts_head.S
+++ b/arch/arm/kvm/interrupts_head.S
@@ -503,6 +503,10 @@ vcpu .req r0 @ vcpu pointer always in r
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
Patches currently in stable-queue which might be from mark.rutland@xxxxxxx are
queue-3.10/arm-hyp-initialize-cntvoff-to-zero.patch
queue-3.10/arm64-virt-ensure-visibility-of-__boot_cpu_mode.patch
queue-3.10/arm-kvm-arch_timers-zero-cntvoff-upon-return-to-host.patch
queue-3.10/clocksource-arch_timer-use-virtual-counters.patch
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