[08/11] Add "wait for page" hypercall.

Commit Message

Gleb Natapov Nov. 1, 2009, 11:56 a.m. UTC

None

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 6c781ea..d404b14 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -456,6 +456,7 @@  struct kvm_vm_stat {
 
 struct kvm_vcpu_stat {
 	u32 pf_fixed;
+	u32 pf_async_wait;
 	u32 pf_guest;
 	u32 tlb_flush;
 	u32 invlpg;
@@ -676,6 +677,7 @@  void kvm_mmu_unload(struct kvm_vcpu *vcpu);
 void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu);
 void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu);
 void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu);
+int kvm_pv_wait_for_async_pf(struct kvm_vcpu *vcpu);
 
 int kvm_emulate_hypercall(struct kvm_vcpu *vcpu);
 
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index abe1ce9..3d33994 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2281,7 +2281,7 @@  static void async_pf_execute(struct slow_work *work)
 					apf->gva);
 
 	if (waitqueue_active(q))
-		wake_up_interruptible(q);
+		wake_up(q);
 
 	mmdrop(apf->mm);
 }
@@ -2351,6 +2351,39 @@  void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
 	async_pf_work_free(work);
 }
 
+static bool kvm_asyc_pf_is_done(struct kvm_vcpu *vcpu)
+{
+	struct kvm_mmu_async_pf *p, *node;
+	bool found = false;
+
+	spin_lock(&vcpu->arch.mmu_async_pf_lock);
+	list_for_each_entry_safe(p, node, &vcpu->arch.mmu_async_pf_done, link) {
+		if (p->guest_task != vcpu->arch.pv_shm->current_task)
+			continue;
+		list_del(&p->link);
+		found = true;
+		break;
+	}
+	spin_unlock(&vcpu->arch.mmu_async_pf_lock);
+	if (found) {
+		vcpu->arch.mmu.page_fault(vcpu, (gpa_t)-1, p->gva,
+					  p->error_code);
+		put_page(p->page);
+		async_pf_work_free(p);
+		trace_kvm_mmu_async_pf_wait(vcpu->arch.pv_shm->current_task, 0);
+	}
+	return found;
+}
+
+int kvm_pv_wait_for_async_pf(struct kvm_vcpu *vcpu)
+{
+	++vcpu->stat.pf_async_wait;
+	trace_kvm_mmu_async_pf_wait(vcpu->arch.pv_shm->current_task, 1);
+	wait_event(vcpu->wq, kvm_asyc_pf_is_done(vcpu));
+
+	return 0;
+}
+
 static bool can_do_async_pf(struct kvm_vcpu *vcpu)
 {
 	struct kvm_segment kvm_seg;
diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h
index d6dd63c..a74f718 100644
--- a/arch/x86/kvm/mmutrace.h
+++ b/arch/x86/kvm/mmutrace.h
@@ -274,6 +274,25 @@  TRACE_EVENT(
 		  __entry->gva, __entry->address, page_to_pfn(__entry->page))
 );
 
+TRACE_EVENT(
+	kvm_mmu_async_pf_wait,
+	TP_PROTO(u64 task, bool wait),
+	TP_ARGS(task, wait),
+
+	TP_STRUCT__entry(
+		__field(u64, task)
+		__field(bool, wait)
+		),
+
+	TP_fast_assign(
+		__entry->task = task;
+		__entry->wait = wait;
+		),
+
+	TP_printk("task %#llx %s", __entry->task, __entry->wait ?
+		  "waits for PF" : "end wait for PF")
+);
+
 #endif /* _TRACE_KVMMMU_H */
 
 /* This part must be outside protection */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e6bd3ad..9208796 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -109,6 +109,7 @@  static DEFINE_PER_CPU(struct kvm_shared_msrs, shared_msrs);
 
 struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ "pf_fixed", VCPU_STAT(pf_fixed) },
+	{ "pf_async_wait", VCPU_STAT(pf_async_wait) },
 	{ "pf_guest", VCPU_STAT(pf_guest) },
 	{ "tlb_flush", VCPU_STAT(tlb_flush) },
 	{ "invlpg", VCPU_STAT(invlpg) },
@@ -3484,6 +3485,10 @@  int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
 	case KVM_HC_SETUP_SHM:
 		r = kvm_pv_setup_shm(vcpu, a0, a1, a2, &ret);
 		break;
+	case KVM_HC_WAIT_FOR_ASYNC_PF:
+		r = kvm_pv_wait_for_async_pf(vcpu);
+		ret = 0;
+		break;
 	default:
 		ret = -KVM_ENOSYS;
 		break;
diff --git a/include/linux/kvm_para.h b/include/linux/kvm_para.h
index 1c37495..50296a6 100644
--- a/include/linux/kvm_para.h
+++ b/include/linux/kvm_para.h
@@ -19,6 +19,7 @@ 
 #define KVM_HC_VAPIC_POLL_IRQ		1
 #define KVM_HC_MMU_OP			2
 #define KVM_HC_SETUP_SHM		3
+#define KVM_HC_WAIT_FOR_ASYNC_PF	4
 
 /*
  * hypercalls use architecture specific