diff mbox

[5/6] KVM: arm/arm64: timer: Check for properly initialized timer on init

Message ID 1481298811-30798-6-git-send-email-marc.zyngier@arm.com
State Accepted
Commit 8e1a0476f8563cadfa32e9b4fff39c4224553b1e
Headers show

Commit Message

Marc Zyngier Dec. 9, 2016, 3:53 p.m. UTC 
From: Christoffer Dall <christoffer.dall@linaro.org>


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 <shihwei@cs.columbia.edu>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

---
 virt/kvm/arm/arch_timer.c | 5 +++++
 1 file changed, 5 insertions(+)

-- 
2.1.4


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diff mbox

Patch

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);