intel-iommu: optimize sg map/unmap calls
This patch adds PageSelectiveInvalidation support replacing existing DomainSelectiveInvalidation for intel_{map/unmap}_sg() calls and also enables to mapping one big contiguous DMA virtual address which is mapped to discontiguous physical address for SG map/unmap calls. "Doamin selective invalidations" wipes out the IOMMU address translation cache based on domain ID where as "Page selective invalidations" wipes out the IOMMU address translation cache for that address mask range which is more cache friendly when compared to Domain selective invalidations. Here is how it is done. 1) changes to iova.c alloc_iova() now takes a bool size_aligned argument, which when when set, returns the io virtual address that is naturally aligned to 2 ^ x, where x is the order of the size requested. Returning this io vitual address which is naturally aligned helps iommu to do the "page selective invalidations" which is IOMMU cache friendly over "domain selective invalidations". 2) Changes to driver/pci/intel-iommu.c Clean up intel_{map/unmap}_{single/sg} () calls so that s/g map/unamp calls is no more dependent on intel_{map/unmap}_single() intel_map_sg() now computes the total DMA virtual address required and allocates the size aligned total DMA virtual address and maps the discontiguous physical address to the allocated contiguous DMA virtual address. In the intel_unmap_sg() case since the DMA virtual address is contiguous and size_aligned, PageSelectiveInvalidation is used replacing earlier DomainSelectiveInvalidations. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Greg KH <greg@kroah.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Suresh B <suresh.b.siddha@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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