[v6,09/12] Inject asynchronous page fault into a PV guest if page is swapped out.

Commit Message

Gleb Natapov Oct. 4, 2010, 3:56 p.m. UTC

None

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index de31551..2f6fc87 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -419,6 +419,7 @@  struct kvm_vcpu_arch {
 		gfn_t gfns[roundup_pow_of_two(ASYNC_PF_PER_VCPU)];
 		struct gfn_to_hva_cache data;
 		u64 msr_val;
+		u32 id;
 	} apf;
 };
 
@@ -594,6 +595,7 @@  struct kvm_x86_ops {
 };
 
 struct kvm_arch_async_pf {
+	u32 token;
 	gfn_t gfn;
 };
 
@@ -842,6 +844,7 @@  void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
 				 struct kvm_async_pf *work);
 void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu,
 			       struct kvm_async_pf *work);
+bool kvm_arch_can_inject_async_page_present(struct kvm_vcpu *vcpu);
 extern bool kvm_find_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn);
 
 #endif /* _ASM_X86_KVM_HOST_H */
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d85fda8..de53cab 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2580,6 +2580,7 @@  static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
 int kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn)
 {
 	struct kvm_arch_async_pf arch;
+	arch.token = (vcpu->arch.apf.id++ << 12) | vcpu->vcpu_id;
 	arch.gfn = gfn;
 
 	return kvm_setup_async_pf(vcpu, gva, gfn, &arch);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3e123ab..0e69d37 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6225,25 +6225,58 @@  static void kvm_del_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
 	}
 }
 
+static int apf_put_user(struct kvm_vcpu *vcpu, u32 val)
+{
+
+	return kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.apf.data, &val,
+				      sizeof(val));
+}
+
 void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,
 				     struct kvm_async_pf *work)
 {
-	vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
-
-	if (work == kvm_double_apf)
+	if (work == kvm_double_apf) {
 		trace_kvm_async_pf_doublefault(kvm_rip_read(vcpu));
-	else {
-		trace_kvm_async_pf_not_present(work->gva);
-
+		vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
+	} else {
+		trace_kvm_async_pf_not_present(work->arch.token, work->gva);
 		kvm_add_async_pf_gfn(vcpu, work->arch.gfn);
+
+		if (!(vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED) ||
+		    kvm_x86_ops->get_cpl(vcpu) == 0)
+			vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
+		else if (!apf_put_user(vcpu, KVM_PV_REASON_PAGE_NOT_PRESENT)) {
+			vcpu->arch.fault.error_code = 0;
+			vcpu->arch.fault.address = work->arch.token;
+			kvm_inject_page_fault(vcpu);
+		}
 	}
 }
 
 void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
 				 struct kvm_async_pf *work)
 {
-	trace_kvm_async_pf_ready(work->gva);
-	kvm_del_async_pf_gfn(vcpu, work->arch.gfn);
+	trace_kvm_async_pf_ready(work->arch.token, work->gva);
+	if (is_error_page(work->page))
+		work->arch.token = ~0; /* broadcast wakeup */
+	else
+		kvm_del_async_pf_gfn(vcpu, work->arch.gfn);
+
+	if ((vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED) &&
+	    !apf_put_user(vcpu, KVM_PV_REASON_PAGE_READY)) {
+		vcpu->arch.fault.error_code = 0;
+		vcpu->arch.fault.address = work->arch.token;
+		kvm_inject_page_fault(vcpu);
+	}
+}
+
+bool kvm_arch_can_inject_async_page_present(struct kvm_vcpu *vcpu)
+{
+	if (!(vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED))
+		return true;
+	else
+		return !kvm_event_needs_reinjection(vcpu) &&
+			kvm_x86_ops->interrupt_allowed(vcpu);
 }
 
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit);
diff --git a/include/trace/events/kvm.h b/include/trace/events/kvm.h
index bcc69b2..dd44aa3 100644
--- a/include/trace/events/kvm.h
+++ b/include/trace/events/kvm.h
@@ -204,34 +204,39 @@  TRACE_EVENT(
 
 TRACE_EVENT(
 	kvm_async_pf_not_present,
-	TP_PROTO(u64 gva),
-	TP_ARGS(gva),
+	TP_PROTO(u64 token, u64 gva),
+	TP_ARGS(token, gva),
 
 	TP_STRUCT__entry(
+		__field(__u64, token)
 		__field(__u64, gva)
 		),
 
 	TP_fast_assign(
+		__entry->token = token;
 		__entry->gva = gva;
 		),
 
-	TP_printk("gva %#llx not present", __entry->gva)
+	TP_printk("token %#llx gva %#llx not present", __entry->token,
+		  __entry->gva)
 );
 
 TRACE_EVENT(
 	kvm_async_pf_ready,
-	TP_PROTO(u64 gva),
-	TP_ARGS(gva),
+	TP_PROTO(u64 token, u64 gva),
+	TP_ARGS(token, gva),
 
 	TP_STRUCT__entry(
+		__field(__u64, token)
 		__field(__u64, gva)
 		),
 
 	TP_fast_assign(
+		__entry->token = token;
 		__entry->gva = gva;
 		),
 
-	TP_printk("gva %#llx ready", __entry->gva)
+	TP_printk("token %#llx gva %#llx ready", __entry->token, __entry->gva)
 );
 
 TRACE_EVENT(
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index 44f4005..d1cd495 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -138,7 +138,8 @@  void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
 		}
 	}
 
-	if (list_empty_careful(&vcpu->async_pf.done))
+	if (list_empty_careful(&vcpu->async_pf.done) ||
+	    !kvm_arch_can_inject_async_page_present(vcpu))
 		return;
 
 	spin_lock(&vcpu->async_pf.lock);