[PATCH 2/9] KVM: MMU: introduce slot_handle_level() and its helper

[guangrong.xiao@linux.intel.com]

From: Xiao Guangrong <guangrong.xiao@linux.intel.com>

There are several places walking all rmaps for the memslot so that
introduce common functions to cleanup the code

Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
---
 arch/x86/kvm/mmu.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ea3e3e4..75a3459 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4410,6 +4410,69 @@ void kvm_mmu_setup(struct kvm_vcpu *vcpu)
 	init_kvm_mmu(vcpu);
 }
 
+/* The return value indicates if tlb flush on all vcpus is needed. */
+typedef bool (*slot_level_handler) (struct kvm *kvm, unsigned long *rmap);
+
+/* The caller should hold mmu-lock before calling this function. */
+static bool
+slot_handle_level(struct kvm *kvm, struct kvm_memory_slot *memslot,
+		  slot_level_handler fn, int min_level, int max_level,
+		  bool lock_flush_tlb)
+{
+	unsigned long last_gfn;
+	bool flush = false;
+	int level;
+
+	last_gfn = memslot->base_gfn + memslot->npages - 1;
+
+	for (level = min_level; level <= max_level; ++level) {
+		unsigned long *rmapp;
+		unsigned long last_index, index;
+
+		rmapp = memslot->arch.rmap[level - PT_PAGE_TABLE_LEVEL];
+		last_index = gfn_to_index(last_gfn, memslot->base_gfn, level);
+
+		for (index = 0; index <= last_index; ++index, ++rmapp) {
+			if (*rmapp)
+				flush |= fn(kvm, rmapp);
+
+			if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
+				if (flush && lock_flush_tlb) {
+					kvm_flush_remote_tlbs(kvm);
+					flush = false;
+				}
+				cond_resched_lock(&kvm->mmu_lock);
+			}
+		}
+	}
+
+	return flush;
+}
+
+static bool
+slot_handle_all_level(struct kvm *kvm, struct kvm_memory_slot *memslot,
+		      slot_level_handler fn, bool lock_flush_tlb)
+{
+	return slot_handle_level(kvm, memslot, fn, PT_PAGE_TABLE_LEVEL,
+		PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES - 1, lock_flush_tlb);
+}
+
+static bool
+slot_handle_large_level(struct kvm *kvm, struct kvm_memory_slot *memslot,
+			slot_level_handler fn, bool lock_flush_tlb)
+{
+	return slot_handle_level(kvm, memslot, fn, PT_PAGE_TABLE_LEVEL + 1,
+		PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES - 1, lock_flush_tlb);
+}
+
+static bool
+slot_handle_leaf(struct kvm *kvm, struct kvm_memory_slot *memslot,
+		 slot_level_handler fn, bool lock_flush_tlb)
+{
+	return slot_handle_level(kvm, memslot, fn, PT_PAGE_TABLE_LEVEL,
+				 PT_PAGE_TABLE_LEVEL, lock_flush_tlb);
+}
+
 void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
 				      struct kvm_memory_slot *memslot)
 {
-- 
1.9.3