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Groups > linux.kernel > #1201163

[PATCH v3 6/10] x86/mm: Fix slow_virt_to_phys() to handle large PAT bit

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slow_virt_to_phys() calls lookup_address() to obtain *pte and
its level.  It then calls pte_pfn() to obtain the PFN for any
level.  This does not result the correct PFN when the large
PAT bit is set because pte_pfn() does not mask the large PAT bit
properly for PUD/PMD.

Fix slow_virt_to_phys() to use pud_pfn() and pmd_pfn() according
to the level.

Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 arch/x86/mm/pageattr.c |   24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 727158c..ecc24e5 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -415,18 +415,28 @@ pmd_t *lookup_pmd_address(unsigned long address)
 phys_addr_t slow_virt_to_phys(void *__virt_addr)
 {
 	unsigned long virt_addr = (unsigned long)__virt_addr;
-	phys_addr_t phys_addr;
-	unsigned long offset;
+	unsigned long phys_addr, offset;
 	enum pg_level level;
-	unsigned long pmask;
 	pte_t *pte;
 
 	pte = lookup_address(virt_addr, &level);
 	BUG_ON(!pte);
-	pmask = page_level_mask(level);
-	offset = virt_addr & ~pmask;
-	phys_addr = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT;
-	return (phys_addr | offset);
+
+	switch (level) {
+	case PG_LEVEL_1G:
+		phys_addr = pud_pfn(*(pud_t *)pte) << PAGE_SHIFT;
+		offset = virt_addr & ~PUD_PAGE_MASK;
+		break;
+	case PG_LEVEL_2M:
+		phys_addr = pmd_pfn(*(pmd_t *)pte) << PAGE_SHIFT;
+		offset = virt_addr & ~PMD_PAGE_MASK;
+		break;
+	default:
+		phys_addr = pte_pfn(*pte) << PAGE_SHIFT;
+		offset = virt_addr & ~PAGE_MASK;
+	}
+
+	return (phys_addr_t)(phys_addr | offset);
 }
 EXPORT_SYMBOL_GPL(slow_virt_to_phys);
 
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[PATCH v3 0/10] x86/mm: Handle large PAT bit in pud/pmd interfaces Toshi Kani <toshi.kani@hp.com> - 2015-08-05 23:50 +0200
  [PATCH v3 9/10] x86/mm: Fix __split_large_page() to handle large PAT bit Toshi Kani <toshi.kani@hp.com> - 2015-08-05 23:50 +0200
  [PATCH v3 1/10] x86/vdso32: Define PGTABLE_LEVELS to 32bit VDSO Toshi Kani <toshi.kani@hp.com> - 2015-08-05 23:50 +0200
  [PATCH v3 10/10] x86/mm: Fix the same pgprot handling in try_preserve_large_page() Toshi Kani <toshi.kani@hp.com> - 2015-08-05 23:50 +0200
  [PATCH v3 6/10] x86/mm: Fix slow_virt_to_phys() to handle large PAT bit Toshi Kani <toshi.kani@hp.com> - 2015-08-05 23:50 +0200
  [PATCH v3 3/10] x86/asm: Fix pud/pmd interfaces to handle large PAT bit Toshi Kani <toshi.kani@hp.com> - 2015-08-05 23:50 +0200
  [PATCH v3 7/10] x86/mm: Fix gup_huge_p?d() to handle large PAT bit Toshi Kani <toshi.kani@hp.com> - 2015-08-05 23:50 +0200
  [PATCH v3 2/10] x86/asm: Move PUD_PAGE macros to page_types.h Toshi Kani <toshi.kani@hp.com> - 2015-08-05 23:50 +0200
  [PATCH v3 8/10] x86/mm: Fix try_preserve_large_page() to handle large PAT bit Toshi Kani <toshi.kani@hp.com> - 2015-08-05 23:50 +0200
  [PATCH v3 5/10] x86/mm: Fix page table dump to show PAT bit Toshi Kani <toshi.kani@hp.com> - 2015-08-05 23:50 +0200

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