On 06/11/2019 15:18, Jan Beulich wrote: > Unmapping a page which has never been mapped should be a no-op (note how > it already is in case there was no root page table allocated).
Which function are you talking about here? iommu_pde_from_dfn() will BUG() if no root was set up. > There's > in particular no need to grow the number of page table levels in use, > and there's also no need to allocate intermediate page tables except > when needing to split a large page. To be honest, I've never been convinced that dynamically changing the number of levels in the AMD IOMMU tables is clever. It should be fixed at 4 (like everything else) and suddenly a lot of runtime complexity disappears. (I'm fairly confident that we'll need a domain create parameter to support 5 level paging in a rational way, so we won't even include walk-length gymnastics then either.) > > Signed-off-by: Jan Beulich <jbeul...@suse.com> Acked-by: Andrew Cooper <andrew.coop...@citrix.com> _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
