[PATCH 3/3] KVM: MMU: Use helpers to clean up walk_addr_generic()

[Takuya Yoshikawa <takuya.yoshikawa@gmail.com>]

From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>

Introduce two new helpers: set_accessed_bit() and is_last_gpte().

These names were suggested by Ingo and Avi.

Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
---
 arch/x86/kvm/paging_tmpl.h |   57 ++++++++++++++++++++++++++++++++-----------
 1 files changed, 42 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 92fe275..d655a4b6 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -113,6 +113,43 @@ static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte)
 	return access;
 }
 
+static int FNAME(set_accessed_bit)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+				   gfn_t table_gfn, unsigned index,
+				   pt_element_t __user *ptep_user,
+				   pt_element_t *ptep)
+{
+	int ret;
+
+	trace_kvm_mmu_set_accessed_bit(table_gfn, index, sizeof(*ptep));
+	ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index,
+				  *ptep, *ptep|PT_ACCESSED_MASK);
+	if (unlikely(ret))
+		return ret;
+
+	mark_page_dirty(vcpu->kvm, table_gfn);
+	*ptep |= PT_ACCESSED_MASK;
+
+	return 0;
+}
+
+static bool FNAME(is_last_gpte)(struct guest_walker *walker,
+				struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+				pt_element_t gpte)
+{
+	if (walker->level == PT_PAGE_TABLE_LEVEL)
+		return true;
+
+	if ((walker->level == PT_DIRECTORY_LEVEL) && is_large_pte(gpte) &&
+	    (PTTYPE == 64 || is_pse(vcpu)))
+		return true;
+
+	if ((walker->level == PT_PDPE_LEVEL) && is_large_pte(gpte) &&
+	    (mmu->root_level == PT64_ROOT_LEVEL))
+		return true;
+
+	return false;
+}
+
 /*
  * Fetch a guest pte for a guest virtual address
  */
@@ -214,31 +251,21 @@ retry_walk:
 
 		if (!eperm && unlikely(!(pte & PT_ACCESSED_MASK))) {
 			int ret;
-			trace_kvm_mmu_set_accessed_bit(table_gfn, index,
-						       sizeof(pte));
-			ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index,
-						  pte, pte|PT_ACCESSED_MASK);
-			if (unlikely(ret < 0)) {
+
+			ret = FNAME(set_accessed_bit)(vcpu, mmu, table_gfn,
+						      index, ptep_user, &pte);
+			if (ret < 0) {
 				errcode |= PFERR_PRESENT_MASK;
 				goto error;
 			} else if (ret)
 				goto retry_walk;
-
-			mark_page_dirty(vcpu->kvm, table_gfn);
-			pte |= PT_ACCESSED_MASK;
 		}
 
 		pte_access = pt_access & FNAME(gpte_access)(vcpu, pte);
 
 		walker->ptes[walker->level - 1] = pte;
 
-		if ((walker->level == PT_PAGE_TABLE_LEVEL) ||
-		    ((walker->level == PT_DIRECTORY_LEVEL) &&
-				is_large_pte(pte) &&
-				(PTTYPE == 64 || is_pse(vcpu))) ||
-		    ((walker->level == PT_PDPE_LEVEL) &&
-				is_large_pte(pte) &&
-				mmu->root_level == PT64_ROOT_LEVEL)) {
+		if (FNAME(is_last_gpte)(walker, vcpu, mmu, pte)) {
 			int lvl = walker->level;
 			gpa_t real_gpa;
 			gfn_t gfn;
-- 
1.7.4.1