On 05/03/2019 16:21, Jan Beulich wrote: >>>> On 05.03.19 at 14:50, <jgr...@suse.com> wrote: >> On 05/03/2019 14:26, Jan Beulich wrote: >>> There are currently three more or less different checks: >>> - _get_page_type() adjusts the IOMMU mappings according to the new type >>> alone, >>> - arch_iommu_populate_page_table() wants just the type to be >>> PGT_writable_page, >>> - iommu_hwdom_init() additionally permits all other types with a type >>> refcount of zero. >>> The canonical one is in _get_page_type(), and as of XSA-288 >>> arch_iommu_populate_page_table() also has no need anymore to deal with >>> PGT_none pages. In the PV Dom0 case, however, PGT_none pages are still >>> necessary to consider, since in that case pages don't get handed to >>> guest_physmap_add_entry(). Furthermore, the function so far also >>> established r/o mappings, which is not in line with the rules set forth >>> by the XSA-288 change. >>> >>> For arch_iommu_populate_page_table() to not encounter PGT_none pages >>> anymore even in cases where the IOMMU gets enabled for a domain only >>> when it is already running, replace the IOMMU dependency in >>> guest_physmap_add_entry()'s handling of PV guests to check just the >>> system wide state instead of the domain property. >>> >>> Signed-off-by: Jan Beulich <jbeul...@suse.com> >> >> I'm unable to decide whether this patch should make it into 4.12 or not >> with the given information. What happens without this patch (worst >> case)? > > I don't think anything really bad can happen, or else this would have > been part of one of the XSAs. The patch is bringing things in line with > what XSA-288 did, without it being obvious what bad could result > from not doing so. The larger part of change here is for hwdom only > anyway.
Okay, thanks. I think this patch should be deferred then. Juergen _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
