[Xen-devel] [PATCH 1/2] arm/traps: fix bug in dump_guest_s1_walk L1 page table offset computation

[Jonathan Daugherty <jtd@xxxxxxxxxx>]

The dump_guest_s1_walk function was incorrectly using the top 10 bits of
the virtual address to select the L1 page table index.  The correct
amount is 12 bits, resulting in a shift of 20 bits rather than 22.

For more details, see the ARMv7-A ARM DDI 0406C.b, section B3.5,
"Short-descriptor translation table format."

Signed-off-by: Jonathan Daugherty <jtd@xxxxxxxxxx>
---
 xen/arch/arm/traps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index a2eb1da..0c10c4d 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2346,7 +2346,7 @@ void dump_guest_s1_walk(struct domain *d, vaddr_t addr)
     }
     first = map_domain_page(mfn);
 
-    offset = addr >> (12+10);
+    offset = addr >> (12+8);
     printk("1ST[0x%"PRIx32"] (0x%"PRIpaddr") = 0x%08"PRIx32"\n",
            offset, pfn_to_paddr(mfn_x(mfn)), first[offset]);
     if ( !(first[offset] & 0x1) ||
-- 
2.9.2


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