KVM: MMU: Use for_each_shadow_entry() in __direct_map()

Eliminating a callback and a useless structure.
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/mmu.c

@@ -1846,67 +1846,42 @@ static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
 {
 }
 
-struct direct_shadow_walk {
-	struct kvm_shadow_walk walker;
-	pfn_t pfn;
-	int write;
-	int largepage;
-	int pt_write;
-};
-
-static int direct_map_entry(struct kvm_shadow_walk *_walk,
-			    struct kvm_vcpu *vcpu,
-			    u64 addr, u64 *sptep, int level)
+static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
+			int largepage, gfn_t gfn, pfn_t pfn)
 {
-	struct direct_shadow_walk *walk =
-		container_of(_walk, struct direct_shadow_walk, walker);
+	struct kvm_shadow_walk_iterator iterator;
 	struct kvm_mmu_page *sp;
+	int pt_write = 0;
 	gfn_t pseudo_gfn;
-	gfn_t gfn = addr >> PAGE_SHIFT;
 
-	if (level == PT_PAGE_TABLE_LEVEL
-	    || (walk->largepage && level == PT_DIRECTORY_LEVEL)) {
-		mmu_set_spte(vcpu, sptep, ACC_ALL, ACC_ALL,
-			     0, walk->write, 1, &walk->pt_write,
-			     walk->largepage, 0, gfn, walk->pfn, false);
+	for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
+		if (iterator.level == PT_PAGE_TABLE_LEVEL
+		    || (largepage && iterator.level == PT_DIRECTORY_LEVEL)) {
+			mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, ACC_ALL,
+				     0, write, 1, &pt_write,
+				     largepage, 0, gfn, pfn, false);
 			++vcpu->stat.pf_fixed;
-		return 1;
+			break;
 		}
 
-	if (*sptep == shadow_trap_nonpresent_pte) {
-		pseudo_gfn = (addr & PT64_DIR_BASE_ADDR_MASK) >> PAGE_SHIFT;
-		sp = kvm_mmu_get_page(vcpu, pseudo_gfn, (gva_t)addr, level - 1,
-				      1, ACC_ALL, sptep);
+		if (*iterator.sptep == shadow_trap_nonpresent_pte) {
+			pseudo_gfn = (iterator.addr & PT64_DIR_BASE_ADDR_MASK) >> PAGE_SHIFT;
+			sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
+					      iterator.level - 1,
+					      1, ACC_ALL, iterator.sptep);
 			if (!sp) {
 				pgprintk("nonpaging_map: ENOMEM\n");
-			kvm_release_pfn_clean(walk->pfn);
+				kvm_release_pfn_clean(pfn);
 				return -ENOMEM;
 			}
 
-		set_shadow_pte(sptep,
+			set_shadow_pte(iterator.sptep,
 				       __pa(sp->spt)
 				       | PT_PRESENT_MASK | PT_WRITABLE_MASK
 				       | shadow_user_mask | shadow_x_mask);
 		}
-	return 0;
-}
-
-static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
-			int largepage, gfn_t gfn, pfn_t pfn)
-{
-	int r;
-	struct direct_shadow_walk walker = {
-		.walker = { .entry = direct_map_entry, },
-		.pfn = pfn,
-		.largepage = largepage,
-		.write = write,
-		.pt_write = 0,
-	};
-
-	r = walk_shadow(&walker.walker, vcpu, gfn << PAGE_SHIFT);
-	if (r < 0)
-		return r;
-	return walker.pt_write;
+	}
+	return pt_write;
 }
 
 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)