From: Allen Kay <allen.m.kay@intel.com>
Date: Fri, 14 Oct 2011 19:32:46 +0000 (-0700)
Subject: intel-iommu: fix superpage support in pfn_to_dma_pte()
X-Git-Tag: firefly_0821_release~7541^2~2117
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=5341e68f9b6c25c0a062de6d730034640988a605;p=firefly-linux-kernel-4.4.55.git

intel-iommu: fix superpage support in pfn_to_dma_pte()

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>
---

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 46fa9eb135cc..0ec8930f31b8 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -307,6 +307,11 @@ static inline bool dma_pte_present(struct dma_pte *pte)
 	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;