Re: [Qemu-devel] [PATCH] arm_gicv3: Add assert()s to tell Coverity that offsets are aligned

[Shannon Zhao <zhaoshenglong@huawei.com>]

On 2016/7/12 2:22, Peter Maydell wrote:
> Coverity complains that the GICR_IPRIORITYR case in gicv3_readl()
> can overflow an array, because it doesn't know that the offsets
> passed to that function must be word aligned. Add some assert()s
> which hopefully tell Coverity that this isn't possible.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> I don't have any way to test this except getting it into master
> and seeing if Coverity still complains, but if it does then
> I'll happily just mark the error as a false positive...
> 
Since the codes are correct, maybe it could ignore the original complain
at Coverity instead of adding the assert(). But anyway I'm fine with
this patch.

>  hw/intc/arm_gicv3_redist.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/hw/intc/arm_gicv3_redist.c b/hw/intc/arm_gicv3_redist.c
> index 2f60096..77e5cfa 100644
> --- a/hw/intc/arm_gicv3_redist.c
> +++ b/hw/intc/arm_gicv3_redist.c
> @@ -420,6 +420,8 @@ MemTxResult gicv3_redist_read(void *opaque, hwaddr offset, uint64_t *data,
>      MemTxResult r;
>      int cpuidx;
>  
> +    assert((offset & (size - 1)) == 0);
> +
>      /* This region covers all the redistributor pages; there are
>       * (for GICv3) two 64K pages per CPU. At the moment they are
>       * all contiguous (ie in this one region), though we might later
> @@ -468,6 +470,8 @@ MemTxResult gicv3_redist_write(void *opaque, hwaddr offset, uint64_t data,
>      MemTxResult r;
>      int cpuidx;
>  
> +    assert((offset & (size - 1)) == 0);
> +
>      /* This region covers all the redistributor pages; there are
>       * (for GICv3) two 64K pages per CPU. At the moment they are
>       * all contiguous (ie in this one region), though we might later
> 

-- 
Shannon