On Tue, Nov 20, 2018 at 09:45:13AM -0700, Jan Beulich wrote:
> >>> On 20.11.18 at 17:01, <roger....@citrix.com> 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....@citrix.com>
> > ---
> > Cc: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com>
> > Cc: Brian Woods <brian.wo...@amd.com>
> > ---
> > 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
>
The original commit 0af438757d455f8eb6b5a6ae9a990ae245f230fd
The commit that adds is_hardware_domain (and rearrange things)
7c275549f46c5c46611592f7107c1345e93ed457
The orginal commit used the function like
setup_dom0_pci_devices(d, amd_iommu_setup_dom0_device);
which was because IOMMU needed to skip the host bridge devices on dom0.
So I assume you added the is_hardware_domain because it only needed to
be done on dom0. I'm not familiar with the IOMMU/PCI history wrt to
what it mapped/passed through so.
--
Brian Woods
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