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intel-iommu: Introduce domain_sg_mapping() to speed up intel_map_sg() 

Instead of calling domain_pfn_mapping() repeatedly with single or
small numbers of pages, just pass the sglist in. It can optimise the
number of cache flushes like domain_pfn_mapping() does, and gives a huge
speedup for large scatterlists.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
David Woodhouse 2009-06-29 11:17:38 +01:00
parent 875764de6f
commit e1605495c7
1 changed files with 62 additions and 21 deletions
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83
drivers/pci/intel-iommu.c
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@ -1635,6 +1635,56 @@ static int domain_context_mapped(struct pci_dev *pdev)
tmp->devfn);
}
static int domain_sg_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
struct scatterlist *sg, unsigned long nr_pages,
int prot)
{
struct dma_pte *first_pte = NULL, *pte = NULL;
uint64_t pteval;
int addr_width = agaw_to_width(domain->agaw) - VTD_PAGE_SHIFT;
unsigned long sg_res = 0;
BUG_ON(addr_width < BITS_PER_LONG && (iov_pfn + nr_pages - 1) >> addr_width);
if ((prot & (DMA_PTE_READ|DMA_PTE_WRITE)) == 0)
return -EINVAL;
prot &= DMA_PTE_READ | DMA_PTE_WRITE | DMA_PTE_SNP;
while (nr_pages--) {
if (!sg_res) {
sg_res = (sg->offset + sg->length + VTD_PAGE_SIZE - 1) >> VTD_PAGE_SHIFT;
sg->dma_address = ((dma_addr_t)iov_pfn << VTD_PAGE_SHIFT) + sg->offset;
sg->dma_length = sg->length;
pteval = page_to_phys(sg_page(sg)) | prot;
}
if (!pte) {
first_pte = pte = pfn_to_dma_pte(domain, iov_pfn);
if (!pte)
return -ENOMEM;
}
/* We don't need lock here, nobody else
* touches the iova range
*/
BUG_ON(dma_pte_addr(pte));
pte->val = pteval;
pte++;
if (!nr_pages ||
(unsigned long)pte >> VTD_PAGE_SHIFT !=
(unsigned long)first_pte >> VTD_PAGE_SHIFT) {
domain_flush_cache(domain, first_pte,
(void *)pte - (void *)first_pte);
pte = NULL;
}
iov_pfn++;
pteval += VTD_PAGE_SIZE;
sg_res--;
if (!sg_res)
sg = sg_next(sg);
}
return 0;
}
static int domain_pfn_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
unsigned long phys_pfn, unsigned long nr_pages,
int prot)
@ -2758,27 +2808,18 @@ static int intel_map_sg(struct device *hwdev, struct scatterlist *sglist, int ne
prot |= DMA_PTE_WRITE;
start_vpfn = mm_to_dma_pfn(iova->pfn_lo);
offset_pfn = 0;
for_each_sg(sglist, sg, nelems, i) {
int nr_pages = aligned_nrpages(sg->offset, sg->length);
ret = domain_pfn_mapping(domain, start_vpfn + offset_pfn,
page_to_dma_pfn(sg_page(sg)),
nr_pages, prot);
if (ret) {
/* clear the page */
dma_pte_clear_range(domain, start_vpfn,
start_vpfn + offset_pfn);
/* free page tables */
dma_pte_free_pagetable(domain, start_vpfn,
start_vpfn + offset_pfn);
/* free iova */
__free_iova(&domain->iovad, iova);
return 0;
}
sg->dma_address = ((dma_addr_t)(start_vpfn + offset_pfn)
<< VTD_PAGE_SHIFT) + sg->offset;
sg->dma_length = sg->length;
offset_pfn += nr_pages;
ret = domain_sg_mapping(domain, start_vpfn, sglist, mm_to_dma_pfn(size), prot);
if (unlikely(ret)) {
/* clear the page */
dma_pte_clear_range(domain, start_vpfn,
start_vpfn + size - 1);
/* free page tables */
dma_pte_free_pagetable(domain, start_vpfn,
start_vpfn + size - 1);
/* free iova */
__free_iova(&domain->iovad, iova);
return 0;
}
/* it's a non-present to present mapping. Only flush if caching mode */