[PATCH v4 1/8] KVM: MMU: Add link_shadow_page() helper

[Avi Kivity <avi@redhat.com>]

To simplify the process of fetching an spte, add a helper that links
a shadow page to an spte.

Reviewed-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/kvm/mmu.c         |   10 ++++++++++
 arch/x86/kvm/paging_tmpl.h |    7 ++-----
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index b93b94f..ae35853 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1482,6 +1482,16 @@ static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
 	--iterator->level;
 }
 
+static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp)
+{
+	u64 spte;
+
+	spte = __pa(sp->spt)
+		| PT_PRESENT_MASK | PT_ACCESSED_MASK
+		| PT_WRITABLE_MASK | PT_USER_MASK;
+	*sptep = spte;
+}
+
 static void kvm_mmu_page_unlink_children(struct kvm *kvm,
 					 struct kvm_mmu_page *sp)
 {
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 6daeacf..4606c88 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -309,7 +309,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
 {
 	unsigned access = gw->pt_access;
 	struct kvm_mmu_page *sp;
-	u64 spte, *sptep = NULL;
+	u64 *sptep = NULL;
 	int direct;
 	gfn_t table_gfn;
 	int r;
@@ -394,10 +394,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
 			}
 		}
 
-		spte = __pa(sp->spt)
-			| PT_PRESENT_MASK | PT_ACCESSED_MASK
-			| PT_WRITABLE_MASK | PT_USER_MASK;
-		*sptep = spte;
+		link_shadow_page(sptep, sp);
 	}
 
 	return sptep;
-- 
1.7.1