KVM: MMU: Add link_shadow_page() helper

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>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 89d7a2cae53b..df3a7a79cce3 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)
 {