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intel-iommu: Performance improvement for domain_pfn_mapping() 

As with dma_pte_clear_range(), don't keep flushing a single PTE at a
time. And also micro-optimise the setting of PTE values rather than
using the helper functions to do all the masking.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
David Woodhouse 2009-06-28 20:38:49 +01:00
parent 310a5ab93c
commit 6f6a00e40a
1 changed files with 17 additions and 9 deletions
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26
drivers/pci/intel-iommu.c
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@ -1639,7 +1639,7 @@ static int domain_pfn_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
unsigned long phys_pfn, unsigned long nr_pages,
int prot)
{
struct dma_pte *pte;
struct dma_pte *first_pte = NULL, *pte = NULL;
int addr_width = agaw_to_width(domain->agaw) - VTD_PAGE_SHIFT;
BUG_ON(addr_width < BITS_PER_LONG && (iov_pfn + nr_pages - 1) >> addr_width);
@ -1647,19 +1647,27 @@ static int domain_pfn_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
if ((prot & (DMA_PTE_READ|DMA_PTE_WRITE)) == 0)
return -EINVAL;
prot &= DMA_PTE_READ | DMA_PTE_WRITE | DMA_PTE_SNP;
while (nr_pages--) {
pte = pfn_to_dma_pte(domain, iov_pfn);
if (!pte)
return -ENOMEM;
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));
dma_set_pte_pfn(pte, phys_pfn);
dma_set_pte_prot(pte, prot);
if (prot & DMA_PTE_SNP)
dma_set_pte_snp(pte);
domain_flush_cache(domain, pte, sizeof(*pte));
pte->val = (phys_pfn << VTD_PAGE_SHIFT) | prot;
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++;
phys_pfn++;
}