[Patchv5 5/7] KVM: async_pf: Allow to wait for outstanding work

From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Gleb Natapov <gleb@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	KVM <kvm@vger.kernel.org>,
	linux-s390 <linux-s390@vger.kernel.org>,
	Dominik Dingel <dingel@linux.vnet.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>
Subject: [Patchv5 5/7] KVM: async_pf: Allow to wait for outstanding work
Date: Tue,  8 Oct 2013 16:54:58 +0200	[thread overview]
Message-ID: <1381244100-59056-6-git-send-email-borntraeger@de.ibm.com> (raw)
In-Reply-To: <1381244100-59056-1-git-send-email-borntraeger@de.ibm.com>

From: Dominik Dingel <dingel@linux.vnet.ibm.com>

kvm_clear_async_pf_completion get an additional flag to either cancel outstanding
work or wait for oustanding work to be finished, x86 currentlx cancels all work.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 arch/x86/kvm/x86.c       | 8 ++++----
 include/linux/kvm_host.h | 2 +-
 virt/kvm/async_pf.c      | 6 +++++-
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 187f824..00a4262 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -539,7 +539,7 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 	kvm_x86_ops->set_cr0(vcpu, cr0);
 
 	if ((cr0 ^ old_cr0) & X86_CR0_PG) {
-		kvm_clear_async_pf_completion_queue(vcpu);
+		kvm_clear_async_pf_completion_queue(vcpu, false);
 		kvm_async_pf_hash_reset(vcpu);
 	}
 
@@ -1911,7 +1911,7 @@ static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data)
 	vcpu->arch.apf.msr_val = data;
 
 	if (!(data & KVM_ASYNC_PF_ENABLED)) {
-		kvm_clear_async_pf_completion_queue(vcpu);
+		kvm_clear_async_pf_completion_queue(vcpu, false);
 		kvm_async_pf_hash_reset(vcpu);
 		return 0;
 	}
@@ -6742,7 +6742,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu)
 
 	kvmclock_reset(vcpu);
 
-	kvm_clear_async_pf_completion_queue(vcpu);
+	kvm_clear_async_pf_completion_queue(vcpu, false);
 	kvm_async_pf_hash_reset(vcpu);
 	vcpu->arch.apf.halted = false;
 
@@ -7015,7 +7015,7 @@ static void kvm_free_vcpus(struct kvm *kvm)
 	 * Unpin any mmu pages first.
 	 */
 	kvm_for_each_vcpu(i, vcpu, kvm) {
-		kvm_clear_async_pf_completion_queue(vcpu);
+		kvm_clear_async_pf_completion_queue(vcpu, false);
 		kvm_unload_vcpu_mmu(vcpu);
 	}
 	kvm_for_each_vcpu(i, vcpu, kvm)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index b4e8666..223fcf3 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -192,7 +192,7 @@ struct kvm_async_pf {
 	struct page *page;
 };
 
-void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu);
+void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu, bool flush);
 void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu);
 int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva,
 		       struct kvm_arch_async_pf *arch);
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index 8f57d63..3e13a73 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -107,7 +107,7 @@ static void async_pf_execute(struct work_struct *work)
 	kvm_put_kvm(vcpu->kvm);
 }
 
-void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
+void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu, bool flush)
 {
 	/* cancel outstanding work queue item */
 	while (!list_empty(&vcpu->async_pf.queue)) {
@@ -115,6 +115,10 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
 			list_entry(vcpu->async_pf.queue.next,
 				   typeof(*work), queue);
 		list_del(&work->queue);
+		if (flush) {
+			flush_work(&work->work);
+			continue;
+		}
 		if (cancel_work_sync(&work->work)) {
 			mmdrop(work->mm);
 			kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */
-- 
1.8.3.1
