RE: [PATCH 16/17] VT-d: show permissions during page table walks

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

> From: Jan Beulich <jbeulich@xxxxxxxx>
> Sent: Tuesday, August 24, 2021 10:27 PM
> 
> Besides the addresses this is the next crucial bit of information one
> might be after.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>

> 
> --- a/xen/drivers/passthrough/vtd/iommu.c
> +++ b/xen/drivers/passthrough/vtd/iommu.c
> @@ -2822,10 +2822,12 @@ static void vtd_dump_page_table_level(pa
>              vtd_dump_page_table_level(dma_pte_addr(*pte), next_level,
>                                        address, indent + 1);
>          else
> -            printk("%*sdfn: %08lx mfn: %08lx\n",
> +            printk("%*sdfn: %08lx mfn: %08lx %c%c\n",
>                     indent, "",
>                     (unsigned long)(address >> PAGE_SHIFT_4K),
> -                   (unsigned long)(dma_pte_addr(*pte) >> PAGE_SHIFT_4K));
> +                   (unsigned long)(dma_pte_addr(*pte) >> PAGE_SHIFT_4K),
> +                   dma_pte_read(*pte) ? 'r' : '-',
> +                   dma_pte_write(*pte) ? 'w' : '-');
>      }
> 
>      unmap_vtd_domain_page(pt_vaddr);
> --- a/xen/drivers/passthrough/vtd/utils.c
> +++ b/xen/drivers/passthrough/vtd/utils.c
> @@ -159,14 +159,11 @@ void print_vtd_entries(struct vtd_iommu
>          l_index = get_level_index(gmfn, level);
>          pte.val = l[l_index];
>          unmap_vtd_domain_page(l);
> -        printk("    l%u[%03x] = %"PRIx64"\n", level, l_index, pte.val);
> +        printk("    l%u[%03x] = %"PRIx64" %c%c\n", level, l_index, pte.val,
> +               dma_pte_read(pte) ? 'r' : '-',
> +               dma_pte_write(pte) ? 'w' : '-');
> 
> -        if ( !dma_pte_present(pte) )
> -        {
> -            printk("    l%u[%03x] not present\n", level, l_index);
> -            break;
> -        }
> -        if ( dma_pte_superpage(pte) )
> +        if ( !dma_pte_present(pte) || dma_pte_superpage(pte) )
>              break;
>          val = dma_pte_addr(pte);
>      } while ( --level );