Re: [Xen-devel] [PATCH v5 6/6] amd/iommu: skip bridge devices when updating IOMMU page tables

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 20.11.18 at 17:01, <roger.pau@xxxxxxxxxx> wrote:
> Bridges are not behind an IOMMU, and are already special cased and
> skipped in amd_iommu_add_device. Apply the same special casing when
> updating page tables.
> 
> This is required or else update_paging_mode will fail and return an
> error to the caller (amd_iommu_{un}map_page) which will destroy the
> domain.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> ---
> Cc: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
> Cc: Brian Woods <brian.woods@xxxxxxx>
> ---
> Changes since v4:
>  - Invert condition order so they match the order in
>    amd_iommu_add_device.
>  - Expand commit message to spell out why this is required.

Thanks. Nevertheless ...

> --- a/xen/drivers/passthrough/amd/iommu_map.c
> +++ b/xen/drivers/passthrough/amd/iommu_map.c
> @@ -612,6 +612,10 @@ static int update_paging_mode(struct domain *d, unsigned 
> long dfn)
>          /* Update device table entries using new root table and paging mode 
> */
>          for_each_pdev( d, pdev )
>          {
> +            if ( pdev->type == DEV_TYPE_PCI_HOST_BRIDGE &&
> +                 is_hardware_domain(d) )
> +                continue;

... before spreading the issue I'd still like to see clarification of /
justification for the is_hardware_domain() part of the condition
you clone. Suravee, Brian?

Jan


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