3 files changed, 42 insertions, 5 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0d70398..167375c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -421,6 +421,7 @@ 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;
 };
 
@@ -596,6 +597,7 @@ struct kvm_x86_ops {
 };
 
 struct kvm_arch_async_pf {
+	u32 token;
 	gfn_t gfn;
 };
 
@@ -819,6 +821,7 @@ 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 b2c6098..64f90db 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2592,6 +2592,7 @@ 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 063c072..ac4c368 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6248,20 +6248,53 @@ 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)
 {
-	trace_kvm_async_pf_not_present(work->gva);
-
-	kvm_make_request(KVM_REQ_APF_HALT, vcpu);
+	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)
+		kvm_make_request(KVM_REQ_APF_HALT, vcpu);
+	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);