Re: [Xen-devel] [PATCH 1/2] arm/traps: fix bug in dump_guest_s1_walk L1 page table offset computation

[Julien Grall <julien.grall@xxxxxxx>]

Hi Jonathan,

Thank you for sending the bug fix.

On 19/07/16 18:15, Jonathan Daugherty wrote:
> The dump_guest_s1_walk function was incorrectly using the top 10 bits of
> the virtual address to select the L1 page table index.  The correct
> amount is 12 bits, resulting in a shift of 20 bits rather than 22.
>
> For more details, see the ARMv7-A ARM, section B3.5, "Short-descriptor
NIT: Could you specify the version of the spec (i.e something similar to 
ARM DDI 0406C.c)?
> translation table format."
>
> Signed-off-by: Jonathan Daugherty <jtd@xxxxxxxxxx>
With the suggestion above:

Reviewed-by: Julien Grall <julien.grall@xxxxxxx>

Regards,

> ---
>  xen/arch/arm/traps.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> index a2eb1da..0c10c4d 100644
> --- a/xen/arch/arm/traps.c
> +++ b/xen/arch/arm/traps.c
> @@ -2346,7 +2346,7 @@ void dump_guest_s1_walk(struct domain *d, vaddr_t addr)
>      }
>      first = map_domain_page(mfn);
>
> -    offset = addr >> (12+10);
> +    offset = addr >> (12+8);
>      printk("1ST[0x%"PRIx32"] (0x%"PRIpaddr") = 0x%08"PRIx32"\n",
>             offset, pfn_to_paddr(mfn_x(mfn)), first[offset]);
>      if ( !(first[offset] & 0x1) ||
--
Julien Grall

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