On 22/01/2019 10:46, Jan Beulich wrote: > >> Regardless of the >> alignment though, the fact that order comes from a hypercall argument and >> may >> not match any of the orders supported by the IOMMU implementation makes me >> think that using a page count is better. > Splitting up guest requests is orthogonal to whether a count or an > order is more suitable as a parameter.
No - this is most certainly not true. Any arbitrary mapping can be expressed with a single map call, given a start/count. This is not true of a start/order pair, so start/count is strictly more expressive. Furthermore, I've already given the following concrete options as to why start/count is better than start/order: Reduced caller looping, reduced TLB flushing in the current implementation, and the fact we literally have hypercalls using this mechanism who's API is stable. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
