[Xen-devel] [PATCH] x86/xen: Warn when there's no mfn for pfn

[Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>]

I recently had to debug dom0 taking a fatal page fault and it would have
been useful if it warned when creating a non-present pte if there's no
mfn for a pfn.

Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
---
 arch/x86/xen/mmu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index adca9e2..4cacc11 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -397,6 +397,7 @@ static pteval_t pte_pfn_to_mfn(pteval_t val)
                 * pte_mfn_to_pfn is asymmetric.
                 */
                if (unlikely(mfn == INVALID_P2M_ENTRY)) {
+                       printk(KERN_WARNING "No mfn for pfn %lx, creating 
non-present pte\n", pfn);
                        mfn = 0;
                        flags = 0;
                } else
-- 
2.1.0


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel