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Subject[19/45] intel-iommu: fix superpage support in pfn_to_dma_pte()
3.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Allen Kay <allen.m.kay@intel.com>

commit 4399c8bf2b9093696fa8160d79712e7346989c46 upstream.

If target_level == 0, current code breaks out of the while-loop if
SUPERPAGE bit is set. We should also break out if PTE is not present.
If we don't do this, KVM calls to iommu_iova_to_phys() will cause
pfn_to_dma_pte() to create mapping for 4KiB pages.

Signed-off-by: Allen Kay <allen.m.kay@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/pci/intel-iommu.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)

--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -307,6 +307,11 @@ static inline bool dma_pte_present(struc
return (pte->val & 3) != 0;
}

+static inline bool dma_pte_superpage(struct dma_pte *pte)
+{
+ return (pte->val & (1 << 7));
+}
+
static inline int first_pte_in_page(struct dma_pte *pte)
{
return !((unsigned long)pte & ~VTD_PAGE_MASK);
@@ -732,29 +737,23 @@ out:
}

static struct dma_pte *pfn_to_dma_pte(struct dmar_domain *domain,
- unsigned long pfn, int large_level)
+ unsigned long pfn, int target_level)
{
int addr_width = agaw_to_width(domain->agaw) - VTD_PAGE_SHIFT;
struct dma_pte *parent, *pte = NULL;
int level = agaw_to_level(domain->agaw);
- int offset, target_level;
+ int offset;

BUG_ON(!domain->pgd);
BUG_ON(addr_width < BITS_PER_LONG && pfn >> addr_width);
parent = domain->pgd;

- /* Search pte */
- if (!large_level)
- target_level = 1;
- else
- target_level = large_level;
-
while (level > 0) {
void *tmp_page;

offset = pfn_level_offset(pfn, level);
pte = &parent[offset];
- if (!large_level && (pte->val & DMA_PTE_LARGE_PAGE))
+ if (!target_level && (dma_pte_superpage(pte) || !dma_pte_present(pte)))
break;
if (level == target_level)
break;



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