linux-kernel - [PATCH 5.8 117/186] iommu/vt-d: Handle 36bit addressing for x86-32

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Message-Id: <20200908152247.308207572@linuxfoundation.org>
Date:   Tue,  8 Sep 2020 17:24:19 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Chris Wilson <chris@...is-wilson.co.uk>,
        Lu Baolu <baolu.lu@...ux.intel.com>,
        James Sewart <jamessewart@...sta.com>,
        Joerg Roedel <jroedel@...e.de>
Subject: [PATCH 5.8 117/186] iommu/vt-d: Handle 36bit addressing for x86-32

From: Chris Wilson <chris@...is-wilson.co.uk>

commit 29aaebbca4abc4cceb38738483051abefafb6950 upstream.

Beware that the address size for x86-32 may exceed unsigned long.

[    0.368971] UBSAN: shift-out-of-bounds in drivers/iommu/intel/iommu.c:128:14
[    0.369055] shift exponent 36 is too large for 32-bit type 'long unsigned int'

If we don't handle the wide addresses, the pages are mismapped and the
device read/writes go astray, detected as DMAR faults and leading to
device failure. The behaviour changed (from working to broken) in commit
fa954e683178 ("iommu/vt-d: Delegate the dma domain to upper layer"), but
the error looks older.

Fixes: fa954e683178 ("iommu/vt-d: Delegate the dma domain to upper layer")
Signed-off-by: Chris Wilson <chris@...is-wilson.co.uk>
Acked-by: Lu Baolu <baolu.lu@...ux.intel.com>
Cc: James Sewart <jamessewart@...sta.com>
Cc: Lu Baolu <baolu.lu@...ux.intel.com>
Cc: Joerg Roedel <jroedel@...e.de>
Cc: <stable@...r.kernel.org> # v5.3+
Link: https://lore.kernel.org/r/20200822160209.28512-1-chris@chris-wilson.co.uk
Signed-off-by: Joerg Roedel <jroedel@...e.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/iommu/intel/iommu.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -123,29 +123,29 @@ static inline unsigned int level_to_offs
 	return (level - 1) * LEVEL_STRIDE;
 }
 
-static inline int pfn_level_offset(unsigned long pfn, int level)
+static inline int pfn_level_offset(u64 pfn, int level)
 {
 	return (pfn >> level_to_offset_bits(level)) & LEVEL_MASK;
 }
 
-static inline unsigned long level_mask(int level)
+static inline u64 level_mask(int level)
 {
-	return -1UL << level_to_offset_bits(level);
+	return -1ULL << level_to_offset_bits(level);
 }
 
-static inline unsigned long level_size(int level)
+static inline u64 level_size(int level)
 {
-	return 1UL << level_to_offset_bits(level);
+	return 1ULL << level_to_offset_bits(level);
 }
 
-static inline unsigned long align_to_level(unsigned long pfn, int level)
+static inline u64 align_to_level(u64 pfn, int level)
 {
 	return (pfn + level_size(level) - 1) & level_mask(level);
 }
 
 static inline unsigned long lvl_to_nr_pages(unsigned int lvl)
 {
-	return  1 << min_t(int, (lvl - 1) * LEVEL_STRIDE, MAX_AGAW_PFN_WIDTH);
+	return 1UL << min_t(int, (lvl - 1) * LEVEL_STRIDE, MAX_AGAW_PFN_WIDTH);
 }
 
 /* VT-d pages must always be _smaller_ than MM pages. Otherwise things