KVM: x86/mmu: Refactor TDP MMU iterators to take kvm_mmu_page root

Instead of passing a pointer to the root page table and the root level
separately, pass in a pointer to the root kvm_mmu_page struct.  This
reduces the number of arguments by 1, cutting down on line lengths.

No functional change intended.
Reviewed-by: Ben Gardon <bgardon@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220119230739.2234394-12-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu/tdp_iter.c

@@ -40,17 +40,19 @@ void tdp_iter_restart(struct tdp_iter *iter)
  * Sets a TDP iterator to walk a pre-order traversal of the paging structure
  * rooted at root_pt, starting with the walk to translate next_last_level_gfn.
  */
-void tdp_iter_start(struct tdp_iter *iter, u64 *root_pt, int root_level,
+void tdp_iter_start(struct tdp_iter *iter, struct kvm_mmu_page *root,
 		    int min_level, gfn_t next_last_level_gfn)
 {
+	int root_level = root->role.level;
+
 	WARN_ON(root_level < 1);
 	WARN_ON(root_level > PT64_ROOT_MAX_LEVEL);
 
 	iter->next_last_level_gfn = next_last_level_gfn;
 	iter->root_level = root_level;
 	iter->min_level = min_level;
-	iter->pt_path[iter->root_level - 1] = (tdp_ptep_t)root_pt;
-	iter->as_id = kvm_mmu_page_as_id(sptep_to_sp(root_pt));
+	iter->pt_path[iter->root_level - 1] = (tdp_ptep_t)root->spt;
+	iter->as_id = kvm_mmu_page_as_id(root);
 
 	tdp_iter_restart(iter);
 }

arch/x86/kvm/mmu/tdp_iter.h

@@ -57,17 +57,17 @@ struct tdp_iter {
  * Iterates over every SPTE mapping the GFN range [start, end) in a
  * preorder traversal.
  */
-#define for_each_tdp_pte_min_level(iter, root, root_level, min_level, start, end) \
-	for (tdp_iter_start(&iter, root, root_level, min_level, start); \
+#define for_each_tdp_pte_min_level(iter, root, min_level, start, end) \
+	for (tdp_iter_start(&iter, root, min_level, start); \
 	     iter.valid && iter.gfn < end;		     \
 	     tdp_iter_next(&iter))
 
-#define for_each_tdp_pte(iter, root, root_level, start, end) \
-	for_each_tdp_pte_min_level(iter, root, root_level, PG_LEVEL_4K, start, end)
+#define for_each_tdp_pte(iter, root, start, end) \
+	for_each_tdp_pte_min_level(iter, root, PG_LEVEL_4K, start, end)
 
 tdp_ptep_t spte_to_child_pt(u64 pte, int level);
 
-void tdp_iter_start(struct tdp_iter *iter, u64 *root_pt, int root_level,
+void tdp_iter_start(struct tdp_iter *iter, struct kvm_mmu_page *root,
 		    int min_level, gfn_t next_last_level_gfn);
 void tdp_iter_next(struct tdp_iter *iter);
 void tdp_iter_restart(struct tdp_iter *iter);

arch/x86/kvm/mmu/tdp_mmu.c

@@ -644,7 +644,7 @@ static inline void tdp_mmu_set_spte_no_dirty_log(struct kvm *kvm,
 }
 
 #define tdp_root_for_each_pte(_iter, _root, _start, _end) \
-	for_each_tdp_pte(_iter, _root->spt, _root->role.level, _start, _end)
+	for_each_tdp_pte(_iter, _root, _start, _end)
 
 #define tdp_root_for_each_leaf_pte(_iter, _root, _start, _end)	\
 	tdp_root_for_each_pte(_iter, _root, _start, _end)		\
@@ -654,8 +654,7 @@ static inline void tdp_mmu_set_spte_no_dirty_log(struct kvm *kvm,
 		else
 
 #define tdp_mmu_for_each_pte(_iter, _mmu, _start, _end)		\
-	for_each_tdp_pte(_iter, __va(_mmu->root_hpa),		\
-			 _mmu->shadow_root_level, _start, _end)
+	for_each_tdp_pte(_iter, to_shadow_page(_mmu->root_hpa), _start, _end)
 
 /*
  * Yield if the MMU lock is contended or this thread needs to return control
@@ -744,8 +743,7 @@ static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
 
 	rcu_read_lock();
 
-	for_each_tdp_pte_min_level(iter, root->spt, root->role.level,
-				   min_level, start, end) {
+	for_each_tdp_pte_min_level(iter, root, min_level, start, end) {
 retry:
 		if (can_yield &&
 		    tdp_mmu_iter_cond_resched(kvm, &iter, flush, shared)) {
@@ -1212,8 +1210,7 @@ static bool wrprot_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
 
 	BUG_ON(min_level > KVM_MAX_HUGEPAGE_LEVEL);
 
-	for_each_tdp_pte_min_level(iter, root->spt, root->role.level,
-				   min_level, start, end) {
+	for_each_tdp_pte_min_level(iter, root, min_level, start, end) {
 retry:
 		if (tdp_mmu_iter_cond_resched(kvm, &iter, false, true))
 			continue;
@@ -1452,8 +1449,7 @@ static bool write_protect_gfn(struct kvm *kvm, struct kvm_mmu_page *root,
 
 	rcu_read_lock();
 
-	for_each_tdp_pte_min_level(iter, root->spt, root->role.level,
-				   min_level, gfn, gfn + 1) {
+	for_each_tdp_pte_min_level(iter, root, min_level, gfn, gfn + 1) {
 		if (!is_shadow_present_pte(iter.old_spte) ||
 		    !is_last_spte(iter.old_spte, iter.level))
 			continue;