KVM: MMU: Fix torn shadow pte

(cherry picked from commit cd5998ebfbc9e6cb44408efa217c15d7eea13675)

The shadow code assigns a pte directly in one place, which is nonatomic on
i386 can can cause random memory references.  Fix by using an atomic setter.

Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 934c7b619396d3ce1426b595069fe53c3ed6bc30..d333a74a1ed339ffd0a0979816726b1220d36619 100644 (file)
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -343,7 +343,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
                shadow_addr = __pa(shadow_page->spt);
                shadow_pte = shadow_addr | PT_PRESENT_MASK | PT_ACCESSED_MASK
                        | PT_WRITABLE_MASK | PT_USER_MASK;
-               *shadow_ent = shadow_pte;
+               set_shadow_pte(shadow_ent, shadow_pte);
        }
 
        mmu_set_spte(vcpu, shadow_ent, access, walker->pte_access & access,