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

[Marc Zyngier]

On 05/12/16 09:32, Christoffer Dall wrote:
> 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 at cs.columbia.edu>
> Signed-off-by: Christoffer Dall <christoffer.dall at linaro.org>
> ---
>  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 27a1f63..5c12f53 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("arch_timer: uninitialized timecounter\n");

For consistency, I'll change the error message to say "kvm_arch_timer",
just like the below case.

> +		return -ENODEV;
> +	}
> +
>  	if (info->virtual_irq <= 0) {
>  		kvm_err("kvm_arch_timer: invalid virtual timer IRQ: %d\n",
>  			info->virtual_irq);
> 

Otherwise looks good to me. I'll queue it now.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...