[PATCH 15/24] kvm: mmu: Wrap mmu_lock cond_resched and needbreak

From: Ben Gardon <bgardon@google.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>, Peter Xu <peterx@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Peter Shier <pshier@google.com>,
	Peter Feiner <pfeiner@google.com>,
	Junaid Shahid <junaids@google.com>,
	Jim Mattson <jmattson@google.com>,
	Yulei Zhang <yulei.kernel@gmail.com>,
	Wanpeng Li <kernellwp@gmail.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Xiao Guangrong <xiaoguangrong.eric@gmail.com>,
	Ben Gardon <bgardon@google.com>
Subject: [PATCH 15/24] kvm: mmu: Wrap mmu_lock cond_resched and needbreak
Date: Tue, 12 Jan 2021 10:10:32 -0800	[thread overview]
Message-ID: <20210112181041.356734-16-bgardon@google.com> (raw)
In-Reply-To: <20210112181041.356734-1-bgardon@google.com>

Wrap the MMU lock cond_reseched and needbreak operations in a function.
This will support a refactoring to move the lock into the struct
kvm_arch(s) so that x86 can change the spinlock to a rwlock without
affecting the performance of other archs.

No functional change intended.

Reviewed-by: Peter Feiner <pfeiner@google.com>

Signed-off-by: Ben Gardon <bgardon@google.com>
---
 arch/arm64/kvm/mmu.c       |  2 +-
 arch/x86/kvm/mmu/mmu.c     | 16 ++++++++--------
 arch/x86/kvm/mmu/tdp_mmu.c |  8 ++++----
 include/linux/kvm_host.h   |  2 ++
 virt/kvm/kvm_main.c        | 10 ++++++++++
 5 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 402b1642c944..57ef1ec23b56 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -58,7 +58,7 @@ static int stage2_apply_range(struct kvm *kvm, phys_addr_t addr,
 			break;
 
 		if (resched && next != end)
-			cond_resched_lock(&kvm->mmu_lock);
+			kvm_mmu_lock_cond_resched(kvm);
 	} while (addr = next, addr != end);
 
 	return ret;
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 5a4577830606..659ed0a2875f 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2016,9 +2016,9 @@ static void mmu_sync_children(struct kvm_vcpu *vcpu,
 			flush |= kvm_sync_page(vcpu, sp, &invalid_list);
 			mmu_pages_clear_parents(&parents);
 		}
-		if (need_resched() || spin_needbreak(&vcpu->kvm->mmu_lock)) {
+		if (need_resched() || kvm_mmu_lock_needbreak(vcpu->kvm)) {
 			kvm_mmu_flush_or_zap(vcpu, &invalid_list, false, flush);
-			cond_resched_lock(&vcpu->kvm->mmu_lock);
+			kvm_mmu_lock_cond_resched(vcpu->kvm);
 			flush = false;
 		}
 	}
@@ -5233,14 +5233,14 @@ slot_handle_level_range(struct kvm *kvm, struct kvm_memory_slot *memslot,
 		if (iterator.rmap)
 			flush |= fn(kvm, iterator.rmap);
 
-		if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
+		if (need_resched() || kvm_mmu_lock_needbreak(kvm)) {
 			if (flush && lock_flush_tlb) {
 				kvm_flush_remote_tlbs_with_address(kvm,
 						start_gfn,
 						iterator.gfn - start_gfn + 1);
 				flush = false;
 			}
-			cond_resched_lock(&kvm->mmu_lock);
+			kvm_mmu_lock_cond_resched(kvm);
 		}
 	}
 
@@ -5390,7 +5390,7 @@ static void kvm_zap_obsolete_pages(struct kvm *kvm)
 		 * be in active use by the guest.
 		 */
 		if (batch >= BATCH_ZAP_PAGES &&
-		    cond_resched_lock(&kvm->mmu_lock)) {
+		    kvm_mmu_lock_cond_resched(kvm)) {
 			batch = 0;
 			goto restart;
 		}
@@ -5688,7 +5688,7 @@ void kvm_mmu_zap_all(struct kvm *kvm)
 			continue;
 		if (__kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list, &ign))
 			goto restart;
-		if (cond_resched_lock(&kvm->mmu_lock))
+		if (kvm_mmu_lock_cond_resched(kvm))
 			goto restart;
 	}
 
@@ -6013,9 +6013,9 @@ static void kvm_recover_nx_lpages(struct kvm *kvm)
 			WARN_ON_ONCE(sp->lpage_disallowed);
 		}
 
-		if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
+		if (need_resched() || kvm_mmu_lock_needbreak(kvm)) {
 			kvm_mmu_commit_zap_page(kvm, &invalid_list);
-			cond_resched_lock(&kvm->mmu_lock);
+			kvm_mmu_lock_cond_resched(kvm);
 		}
 	}
 	kvm_mmu_commit_zap_page(kvm, &invalid_list);
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 90807f2d928f..fb911ca428b2 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -488,10 +488,10 @@ static inline void tdp_mmu_set_spte_no_dirty_log(struct kvm *kvm,
 static bool tdp_mmu_iter_flush_cond_resched(struct kvm *kvm,
 		struct tdp_iter *iter)
 {
-	if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
+	if (need_resched() || kvm_mmu_lock_needbreak(kvm)) {
 		kvm_flush_remote_tlbs(kvm);
 		rcu_read_unlock();
-		cond_resched_lock(&kvm->mmu_lock);
+		kvm_mmu_lock_cond_resched(kvm);
 		rcu_read_lock();
 		tdp_iter_refresh_walk(iter);
 		return true;
@@ -512,9 +512,9 @@ static bool tdp_mmu_iter_flush_cond_resched(struct kvm *kvm,
  */
 static bool tdp_mmu_iter_cond_resched(struct kvm *kvm, struct tdp_iter *iter)
 {
-	if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
+	if (need_resched() || kvm_mmu_lock_needbreak(kvm)) {
 		rcu_read_unlock();
-		cond_resched_lock(&kvm->mmu_lock);
+		kvm_mmu_lock_cond_resched(kvm);
 		rcu_read_lock();
 		tdp_iter_refresh_walk(iter);
 		return true;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 433d14fdae30..6e2773fc406c 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1497,5 +1497,7 @@ static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu)
 
 void kvm_mmu_lock(struct kvm *kvm);
 void kvm_mmu_unlock(struct kvm *kvm);
+int kvm_mmu_lock_needbreak(struct kvm *kvm);
+int kvm_mmu_lock_cond_resched(struct kvm *kvm);
 
 #endif
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 32f97ed1188d..b4c49a7e0556 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -442,6 +442,16 @@ void kvm_mmu_unlock(struct kvm *kvm)
 	spin_unlock(&kvm->mmu_lock);
 }
 
+int kvm_mmu_lock_needbreak(struct kvm *kvm)
+{
+	return spin_needbreak(&kvm->mmu_lock);
+}
+
+int kvm_mmu_lock_cond_resched(struct kvm *kvm)
+{
+	return cond_resched_lock(&kvm->mmu_lock);
+}
+
 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
 static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
 {
-- 
2.30.0.284.gd98b1dd5eaa7-goog

