Messages in this thread | | | Date | Mon, 11 Dec 2023 13:38:26 -0400 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v2 1/6] iommu/vt-d: Setup scalable mode context entry in probe path |
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On Tue, Dec 05, 2023 at 09:21:58AM +0800, Lu Baolu wrote: > +/* > + * Get the PASID directory size for scalable mode context entry. > + * Value of X in the PDTS field of a scalable mode context entry > + * indicates PASID directory with 2^(X + 7) entries. > + */ > +static unsigned long context_get_sm_pds(struct pasid_table *table) > +{ > + unsigned long pds, max_pde; > + > + max_pde = table->max_pasid >> PASID_PDE_SHIFT; > + pds = find_first_bit(&max_pde, MAX_NR_PASID_BITS); > + if (pds < 7) > + return 0; > + > + return pds - 7;
This seems like a convoluted way to write max(ilog2(table-max_pasid) - 7,0)
?
Jason
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