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Commit 688bc577 authored by Marc Zyngier's avatar Marc Zyngier
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arm: KVM: Disable virtual timer even if the guest is not using it 



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.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent c4cbba9f

arch/arm/kvm/interrupts_head.S

+4 −2
Original line number Diff line number Diff line
@@ -515,8 +515,7 @@ ARM_BE8(rev r6, r6 ) 


	mrc	p15, 0, r2, c14, c3, 1	@ CNTV_CTL

	str	r2, [vcpu, #VCPU_TIMER_CNTV_CTL]

	bic	r2, #1			@ Clear ENABLE

	mcr	p15, 0, r2, c14, c3, 1	@ CNTV_CTL



	isb



	mrrc	p15, 3, rr_lo_hi(r2, r3), c14	@ CNTV_CVAL
@@ -529,6 +528,9 @@ ARM_BE8(rev r6, r6 ) 
	mcrr	p15, 4, r2, r2, c14	@ CNTVOFF



1:

	mov	r2, #0			@ Clear ENABLE

	mcr	p15, 0, r2, c14, c3, 1	@ CNTV_CTL



	@ Allow physical timer/counter access for the host

	mrc	p15, 4, r2, c14, c1, 0	@ CNTHCTL

	orr	r2, r2, #(CNTHCTL_PL1PCEN | CNTHCTL_PL1PCTEN)