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

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@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>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This commit is contained in:

Mark Rutland

2013-03-26 13:41:35 +00:00

committed by

Greg Kroah-Hartman

parent 3db87d4c3a

commit 6e7be6fc3e

1 changed files with 4 additions and 0 deletions

									
										arch/arm/kvm/interrupts_head.S
									
		+4
		
												View File
												
				@@ -503,6 +503,10 @@ 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