Re: [PATCH] kvm: use PIT channel index in hpet_legacy_start mode

[Yang Zhang <yang.zhang.wz@gmail.com>]

On 2016/1/7 20:32, P J P wrote:
> From: P J P <pjp@fedoraproject.org>
>
> While setting the KVM PIT counters in 'kvm_pit_load_count', if
> 'hpet_legacy_start' is set, the function disables the timer on
> channel[0], instead of the respective index 'channel'. Update it
> to use 'channel' index parameter.
>
> Signed-off-by: P J P <pjp@fedoraproject.org>
> ---
>   arch/x86/kvm/i8254.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
> index 08116ff..154e936 100644
> --- a/arch/x86/kvm/i8254.c
> +++ b/arch/x86/kvm/i8254.c
> @@ -420,10 +420,11 @@ void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_s
>   	u8 saved_mode;
>   	if (hpet_legacy_start) {
>   		/* save existing mode for later reenablement */
> -		saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
> -		kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
> +		saved_mode = kvm->arch.vpit->pit_state.channels[channel].mode;
> +		/* disable timer */
> +		kvm->arch.vpit->pit_state.channels[channel].mode = 0xff;
>   		pit_load_count(kvm, channel, val);
> -		kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
> +		kvm->arch.vpit->pit_state.channels[channel].mode = saved_mode;
>   	} else {
>   		pit_load_count(kvm, channel, val);
>   	}
>

Will this trigger the same issue like CVE-2015-7513 ?

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=0185604c2d82c560dab2f2933a18f797e74ab5a8

-- 
best regards
yang