>>> On 27.07.17 at 18:19, <george.dun...@eu.citrix.com> wrote: > On Wed, Jul 5, 2017 at 11:05 AM, Jan Beulich <jbeul...@suse.com> wrote: >> Calculate entry PFN and flags just once. Convert the two successive >> main if()-s to and if/elf-if chain. Restrict variable scope where >> reasonable. Take the opportunity and also make the induction variable >> unsigned. >> >> Signed-off-by: Jan Beulich <jbeul...@suse.com> >> --- >> v2: Re-do mostly from scratch following review feedback. >> Note: I have trouble seeing how the old code worked, when the 2M page >> shattering path specified neither read nor write permission for >> the IOMMU. Am I overlooking a reason why this was (and should >> remain) so? > > Hmm -- given that in all other circumstances, a 4k page which is > ram_rw gets RW, then I think the old code must certainly be buggy. > > But is your code correct? It looks like you unconditionally give it > RW, when for ram_ro, for example it should be R (not W). It seems > like we should either call p2m_get_iommu_flags(), or ASSERT() that the > resulting flags would be RW.
Hmm, good point, but that means the original code had the same issue when splitting 1G into 2M pages. I'd prefer to not call p2m_get_iommu_flags() though, but instead simply inherit the IOMMU flags from the original large page. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
