From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Fri, 9 Dec 2016 15:53:30 +0000 Subject: [PATCH 5/6] KVM: arm/arm64: timer: Check for properly initialized timer on init In-Reply-To: <1481298811-30798-1-git-send-email-marc.zyngier@arm.com> References: <1481298811-30798-1-git-send-email-marc.zyngier@arm.com> Message-ID: <1481298811-30798-6-git-send-email-marc.zyngier@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Christoffer Dall When the arch timer code fails to initialize (for example because the memory mapped timer doesn't work, which is currently seen with the AEM model), then KVM just continues happily with a final result that KVM eventually does a NULL pointer dereference of the uninitialized cycle counter. Check directly for this in the init path and give the user a reasonable error in this case. Cc: Shih-Wei Li Signed-off-by: Christoffer Dall Signed-off-by: Marc Zyngier --- virt/kvm/arm/arch_timer.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index 17b8fa5..ae95fc0 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -425,6 +425,11 @@ int kvm_timer_hyp_init(void) info = arch_timer_get_kvm_info(); timecounter = &info->timecounter; + if (!timecounter->cc) { + kvm_err("kvm_arch_timer: uninitialized timecounter\n"); + return -ENODEV; + } + if (info->virtual_irq <= 0) { kvm_err("kvm_arch_timer: invalid virtual timer IRQ: %d\n", info->virtual_irq); -- 2.1.4