KVM: x86/xen: setup pvclock updates

Parameterise kvm_setup_pvclock_page() a little bit so that it can be
invoked for different gfn_to_hva_cache structures, and with different
offsets. Then we can invoke it for the normal KVM pvclock and also for
the Xen one in the vcpu_info.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>

arch/x86/kvm/x86.c

@@ -2610,13 +2610,15 @@ u64 get_kvmclock_ns(struct kvm *kvm)
 	return ret;
 }
 
-static void kvm_setup_pvclock_page(struct kvm_vcpu *v)
+static void kvm_setup_pvclock_page(struct kvm_vcpu *v,
+				   struct gfn_to_hva_cache *cache,
+				   unsigned int offset)
 {
 	struct kvm_vcpu_arch *vcpu = &v->arch;
 	struct pvclock_vcpu_time_info guest_hv_clock;
 
-	if (unlikely(kvm_read_guest_cached(v->kvm, &vcpu->pv_time,
-		&guest_hv_clock, sizeof(guest_hv_clock))))
+	if (unlikely(kvm_read_guest_offset_cached(v->kvm, cache,
+		&guest_hv_clock, offset, sizeof(guest_hv_clock))))
 		return;
 
 	/* This VCPU is paused, but it's legal for a guest to read another
@@ -2639,9 +2641,9 @@ static void kvm_setup_pvclock_page(struct kvm_vcpu *v)
 		++guest_hv_clock.version;  /* first time write, random junk */
 
 	vcpu->hv_clock.version = guest_hv_clock.version + 1;
-	kvm_write_guest_cached(v->kvm, &vcpu->pv_time,
-				&vcpu->hv_clock,
-				sizeof(vcpu->hv_clock.version));
+	kvm_write_guest_offset_cached(v->kvm, cache,
+				      &vcpu->hv_clock, offset,
+				      sizeof(vcpu->hv_clock.version));
 
 	smp_wmb();
 
@@ -2655,16 +2657,16 @@ static void kvm_setup_pvclock_page(struct kvm_vcpu *v)
 
 	trace_kvm_pvclock_update(v->vcpu_id, &vcpu->hv_clock);
 
-	kvm_write_guest_cached(v->kvm, &vcpu->pv_time,
-				&vcpu->hv_clock,
-				sizeof(vcpu->hv_clock));
+	kvm_write_guest_offset_cached(v->kvm, cache,
+				      &vcpu->hv_clock, offset,
+				      sizeof(vcpu->hv_clock));
 
 	smp_wmb();
 
 	vcpu->hv_clock.version++;
-	kvm_write_guest_cached(v->kvm, &vcpu->pv_time,
-				&vcpu->hv_clock,
-				sizeof(vcpu->hv_clock.version));
+	kvm_write_guest_offset_cached(v->kvm, cache,
+				     &vcpu->hv_clock, offset,
+				     sizeof(vcpu->hv_clock.version));
 }
 
 static int kvm_guest_time_update(struct kvm_vcpu *v)
@@ -2751,7 +2753,10 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
 	vcpu->hv_clock.flags = pvclock_flags;
 
 	if (vcpu->pv_time_enabled)
-		kvm_setup_pvclock_page(v);
+		kvm_setup_pvclock_page(v, &vcpu->pv_time, 0);
+	if (vcpu->xen.vcpu_info_set)
+		kvm_setup_pvclock_page(v, &vcpu->xen.vcpu_info_cache,
+				       offsetof(struct compat_vcpu_info, time));
 	if (v == kvm_get_vcpu(v->kvm, 0))
 		kvm_hv_setup_tsc_page(v->kvm, &vcpu->hv_clock);
 	return 0;

arch/x86/kvm/xen.c

@@ -135,11 +135,12 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 					      &vcpu->arch.xen.vcpu_info_cache,
 					      data->u.gpa,
 					      sizeof(struct vcpu_info));
-		if (!r)
+		if (!r) {
 			vcpu->arch.xen.vcpu_info_set = true;
+			kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
+		}
 		break;
 
-
 	default:
 		break;
 	}