Re: [PATCH] arm/arm64: KVM: Fix set_clear_sgi_pend_reg offset

[Shannon Zhao <zhaoshenglong@huawei.com>]

On 2014/9/26 1:49, Christoffer Dall wrote:
> The sgi values calculated in read_set_clear_sgi_pend_reg() and
> write_set_clear_sgi_pend_reg() were horribly incorrectly multiplied by 4
> with catastrophic results in that subfunctions ended up overwriting
> memory not allocated for the expected purpose.
> 
> This showed up as bugs in kfree() and the kernel complaining a lot of
> you turn on memory debugging.
> 
> This addresses: http://marc.info/?l=kvm&m=141164910007868&w=2
> 
> Reported-by: Shannon Zhao <zhaoshenglong@huawei.com>
> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
> ---
>  virt/kvm/arm/vgic.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
> index b6fab0f..8629678 100644
> --- a/virt/kvm/arm/vgic.c
> +++ b/virt/kvm/arm/vgic.c
> @@ -816,7 +816,7 @@ static bool read_set_clear_sgi_pend_reg(struct kvm_vcpu *vcpu,
>  {
>  	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
>  	int sgi;
> -	int min_sgi = (offset & ~0x3) * 4;
> +	int min_sgi = (offset & ~0x3);
>  	int max_sgi = min_sgi + 3;
>  	int vcpu_id = vcpu->vcpu_id;
>  	u32 reg = 0;
> @@ -837,7 +837,7 @@ static bool write_set_clear_sgi_pend_reg(struct kvm_vcpu *vcpu,
>  {
>  	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
>  	int sgi;
> -	int min_sgi = (offset & ~0x3) * 4;
> +	int min_sgi = (offset & ~0x3);
>  	int max_sgi = min_sgi + 3;
>  	int vcpu_id = vcpu->vcpu_id;
>  	u32 reg;
> 
Tested-by: Shannon Zhao <zhaoshenglong@huawei.com>
-- 
Shannon