[RFC][PATCH 1/2] kvm: x86: mmu: return zero if s > e in rsvd_bits()

[Tiejun Chen <tiejun.chen@xxxxxxxxx>]

In some real scenarios 'start' may not be less than 'end' like
maxphyaddr = 52.

Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
---
 arch/x86/kvm/mmu.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index bde8ee7..0e98b5e 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -58,6 +58,8 @@
 
 static inline u64 rsvd_bits(int s, int e)
 {
+	if (unlikely(s > e))
+		return 0;
 	return ((1ULL << (e - s + 1)) - 1) << s;
 }
 
-- 
1.9.1

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