x86/xen: fix set_phys_range_identity() if pfn_e > MAX_P2M_PFN

Allow set_phys_range_identity() to work with a range that overlaps
MAX_P2M_PFN by clamping pfn_e to MAX_P2M_PFN.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 4fc71cc1705b..82c8c9305510 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -774,7 +774,7 @@ unsigned long __init set_phys_range_identity(unsigned long pfn_s,
 {
         unsigned long pfn;
 
-        if (unlikely(pfn_s >= MAX_P2M_PFN || pfn_e >= MAX_P2M_PFN))
+        if (unlikely(pfn_s >= MAX_P2M_PFN))
                 return 0;
 
         if (unlikely(xen_feature(XENFEAT_auto_translated_physmap)))
@@ -783,6 +783,9 @@ unsigned long __init set_phys_range_identity(unsigned long pfn_s,
         if (pfn_s > pfn_e)
                 return 0;
 
+        if (pfn_e > MAX_P2M_PFN)
+                pfn_e = MAX_P2M_PFN;
+
         for (pfn = (pfn_s & ~(P2M_MID_PER_PAGE * P2M_PER_PAGE - 1));
                 pfn < ALIGN(pfn_e, (P2M_MID_PER_PAGE * P2M_PER_PAGE));
                 pfn += P2M_MID_PER_PAGE * P2M_PER_PAGE)