From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Wed, 16 Sep 2015 16:58:07 +0100 Subject: [PATCH 3/3] arm: KVM: Disable virtual timer even if the guest is not using it In-Reply-To: <1442419087-24648-1-git-send-email-marc.zyngier@arm.com> References: <1442419087-24648-1-git-send-email-marc.zyngier@arm.com> Message-ID: <1442419087-24648-4-git-send-email-marc.zyngier@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 at vger.kernel.org Signed-off-by: Marc Zyngier --- arch/arm/kvm/interrupts_head.S | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S index 702740d..51a5950 100644 --- a/arch/arm/kvm/interrupts_head.S +++ b/arch/arm/kvm/interrupts_head.S @@ -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) -- 2.1.4