From 8e1a0476f8563cadfa32e9b4fff39c4224553b1e Mon Sep 17 00:00:00 2001
From: Christoffer Dall <christoffer.dall@linaro.org>
Date: Mon, 5 Dec 2016 10:32:11 +0100
Subject: [PATCH] KVM: arm/arm64: timer: Check for properly initialized timer
on init
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(+)
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index 17b8fa52bf3b..ae95fc0e3214 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);
--
2.30.9