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iommu/vt-d: Clean up size handling for intel_iommu_unmap()

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We have this horrid API where iommu_unmap() can unmap more than it's asked
to, if the IOVA in question happens to be mapped with a large page.

Instead of propagating this nonsense to the point where we end up returning
the page order from dma_pte_clear_range(), let's just do it once and adjust
the 'size' parameter accordingly.

Augment pfn_to_dma_pte() to return the level at which the PTE was found,
which will also be useful later if we end up changing the API for
iommu_iova_to_phys() to behave the same way as is being discussed upstream.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
David Woodhouse 2014-03-19 16:07:49 +00:00
parent 75f05569d0
commit 5cf0a76fa2
1 changed files with 25 additions and 12 deletions
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37
drivers/iommu/intel-iommu.c
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@ -784,7 +784,7 @@ out:
}
static struct dma_pte *pfn_to_dma_pte(struct dmar_domain *domain,
unsigned long pfn, int target_level)
unsigned long pfn, int *target_level)
{
int addr_width = agaw_to_width(domain->agaw) - VTD_PAGE_SHIFT;
struct dma_pte *parent, *pte = NULL;
@ -799,14 +799,14 @@ static struct dma_pte *pfn_to_dma_pte(struct dmar_domain *domain,
parent = domain->pgd;
while (level > 0) {
while (1) {
void *tmp_page;
offset = pfn_level_offset(pfn, level);
pte = &parent[offset];
if (!target_level && (dma_pte_superpage(pte) || !dma_pte_present(pte)))
if (!*target_level && (dma_pte_superpage(pte) || !dma_pte_present(pte)))
break;
if (level == target_level)
if (level == *target_level)
break;
if (!dma_pte_present(pte)) {
@ -827,10 +827,16 @@ static struct dma_pte *pfn_to_dma_pte(struct dmar_domain *domain,
domain_flush_cache(domain, pte, sizeof(*pte));
}
}
if (level == 1)
break;
parent = phys_to_virt(dma_pte_addr(pte));
level--;
}
if (!*target_level)
*target_level = level;
return pte;
}
@ -868,7 +874,7 @@ static struct dma_pte *dma_pfn_level_pte(struct dmar_domain *domain,
}
/* clear last level pte, a tlb flush should be followed */
static int dma_pte_clear_range(struct dmar_domain *domain,
static void dma_pte_clear_range(struct dmar_domain *domain,
unsigned long start_pfn,
unsigned long last_pfn)
{
@ -898,8 +904,6 @@ static int dma_pte_clear_range(struct dmar_domain *domain,
(void *)pte - (void *)first_pte);
} while (start_pfn && start_pfn <= last_pfn);
return min_t(int, (large_page - 1) * 9, MAX_AGAW_PFN_WIDTH);
}
static void dma_pte_free_level(struct dmar_domain *domain, int level,
@ -1832,7 +1836,7 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
if (!pte) {
largepage_lvl = hardware_largepage_caps(domain, iov_pfn, phys_pfn, sg_res);
first_pte = pte = pfn_to_dma_pte(domain, iov_pfn, largepage_lvl);
first_pte = pte = pfn_to_dma_pte(domain, iov_pfn, &largepage_lvl);
if (!pte)
return -ENOMEM;
/* It is large page*/
@ -4099,15 +4103,23 @@ static size_t intel_iommu_unmap(struct iommu_domain *domain,
unsigned long iova, size_t size)
{
struct dmar_domain *dmar_domain = domain->priv;
int order;
int level = 0;
order = dma_pte_clear_range(dmar_domain, iova >> VTD_PAGE_SHIFT,
/* Cope with horrid API which requires us to unmap more than the
size argument if it happens to be a large-page mapping. */
if (!pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level))
BUG();
if (size < VTD_PAGE_SIZE << level_to_offset_bits(level))
size = VTD_PAGE_SIZE << level_to_offset_bits(level);
dma_pte_clear_range(dmar_domain, iova >> VTD_PAGE_SHIFT,
(iova + size - 1) >> VTD_PAGE_SHIFT);
if (dmar_domain->max_addr == iova + size)
dmar_domain->max_addr = iova;
return PAGE_SIZE << order;
return size;
}
static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
@ -4115,9 +4127,10 @@ static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
{
struct dmar_domain *dmar_domain = domain->priv;
struct dma_pte *pte;
int level = 0;
u64 phys = 0;
pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, 0);
pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level);
if (pte)
phys = dma_pte_addr(pte);