[PATCH 2/2] KVM: MMU: fix relaxing permission
From: Xiao Guangrong
Date: Tue May 25 2010 - 22:50:03 EST
There is a relaxing permission operation in set_spte():
if guest's CR0.WP is not set and R/W #PF occurs in supervisor-level,
the mapping path might set to writable, then user can allow to write.
Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index bfd8382..ccbc98b 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1859,8 +1859,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
spte |= (u64)pfn << PAGE_SHIFT;
- if ((pte_access & ACC_WRITE_MASK)
- || (write_fault && !is_write_protection(vcpu) && !user_fault)) {
+ if (pte_access & ACC_WRITE_MASK) {
if (level > PT_PAGE_TABLE_LEVEL &&
has_wrprotected_page(vcpu->kvm, gfn, level)) {
--
1.6.1.2
--
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