[PATCH v2 1/5] mmu: extend the is_present check to 32 bits

From	Bandan Das <bsd@redhat.com>
Newsgroups	linux.kernel
Subject	[PATCH v2 1/5] mmu: extend the is_present check to 32 bits
Date	2016-07-13 00:20 +0200
Message-ID	<rUec2-2Bd-7@gated-at.bofh.it> (permalink)
References	<rUec2-2Bd-9@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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This is safe because this function is called
on host controlled page table and non-present/non-MMIO
sptes never use bits 1..31. For the EPT case, this
ensures that cases where only the execute bit is set
is marked valid.

Signed-off-by: Bandan Das <bsd@redhat.com>
---
 arch/x86/kvm/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index def97b3..87b62dc 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -304,7 +304,7 @@ static int is_nx(struct kvm_vcpu *vcpu)
 
 static int is_shadow_present_pte(u64 pte)
 {
-	return pte & PT_PRESENT_MASK && !is_mmio_spte(pte);
+	return (pte & 0xFFFFFFFFull) && !is_mmio_spte(pte);
 }
 
 static int is_large_pte(u64 pte)
-- 
2.5.5

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[PATCH v2 1/5] mmu: extend the is_present check to 32 bits Bandan Das <bsd@redhat.com> - 2016-07-13 00:20 +0200

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