KVM: PPC: Book3S: Add support for ibm,int-on/off RTAS calls

This adds support for the ibm,int-on and ibm,int-off RTAS calls to the
in-kernel XICS emulation and corrects the handling of the saved
priority by the ibm,set-xive RTAS call.  With this, ibm,int-off sets
the specified interrupt's priority in its saved_priority field and
sets the priority to 0xff (the least favoured value).  ibm,int-on
restores the saved_priority to the priority field, and ibm,set-xive
sets both the priority and the saved_priority to the specified
priority value.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/include/asm/kvm_ppc.h

@@ -174,6 +174,8 @@ extern int kvmppc_xics_set_xive(struct kvm *kvm, u32 irq, u32 server,
 				u32 priority);
 extern int kvmppc_xics_get_xive(struct kvm *kvm, u32 irq, u32 *server,
 				u32 *priority);
+extern int kvmppc_xics_int_on(struct kvm *kvm, u32 irq);
+extern int kvmppc_xics_int_off(struct kvm *kvm, u32 irq);
 
 /*
  * Cuts out inst bits with ordering according to spec.

arch/powerpc/kvm/book3s_rtas.c

@@ -63,6 +63,44 @@ static void kvm_rtas_get_xive(struct kvm_vcpu *vcpu, struct rtas_args *args)
 out:
 	args->rets[0] = rc;
 }
+
+static void kvm_rtas_int_off(struct kvm_vcpu *vcpu, struct rtas_args *args)
+{
+	u32 irq;
+	int rc;
+
+	if (args->nargs != 1 || args->nret != 1) {
+		rc = -3;
+		goto out;
+	}
+
+	irq = args->args[0];
+
+	rc = kvmppc_xics_int_off(vcpu->kvm, irq);
+	if (rc)
+		rc = -3;
+out:
+	args->rets[0] = rc;
+}
+
+static void kvm_rtas_int_on(struct kvm_vcpu *vcpu, struct rtas_args *args)
+{
+	u32 irq;
+	int rc;
+
+	if (args->nargs != 1 || args->nret != 1) {
+		rc = -3;
+		goto out;
+	}
+
+	irq = args->args[0];
+
+	rc = kvmppc_xics_int_on(vcpu->kvm, irq);
+	if (rc)
+		rc = -3;
+out:
+	args->rets[0] = rc;
+}
 #endif /* CONFIG_KVM_XICS */
 
 struct rtas_handler {
@@ -74,6 +112,8 @@ static struct rtas_handler rtas_handlers[] = {
 #ifdef CONFIG_KVM_XICS
 	{ .name = "ibm,set-xive", .handler = kvm_rtas_set_xive },
 	{ .name = "ibm,get-xive", .handler = kvm_rtas_get_xive },
+	{ .name = "ibm,int-off",  .handler = kvm_rtas_int_off },
+	{ .name = "ibm,int-on",   .handler = kvm_rtas_int_on },
 #endif
 };
 

arch/powerpc/kvm/book3s_xics.c

@@ -123,14 +123,35 @@ static void ics_check_resend(struct kvmppc_xics *xics, struct kvmppc_ics *ics,
 	mutex_unlock(&ics->lock);
 }
 
+static bool write_xive(struct kvmppc_xics *xics, struct kvmppc_ics *ics,
+		       struct ics_irq_state *state,
+		       u32 server, u32 priority, u32 saved_priority)
+{
+	bool deliver;
+
+	mutex_lock(&ics->lock);
+
+	state->server = server;
+	state->priority = priority;
+	state->saved_priority = saved_priority;
+	deliver = false;
+	if ((state->masked_pending || state->resend) && priority != MASKED) {
+		state->masked_pending = 0;
+		deliver = true;
+	}
+
+	mutex_unlock(&ics->lock);
+
+	return deliver;
+}
+
 int kvmppc_xics_set_xive(struct kvm *kvm, u32 irq, u32 server, u32 priority)
 {
 	struct kvmppc_xics *xics = kvm->arch.xics;
 	struct kvmppc_icp *icp;
 	struct kvmppc_ics *ics;
 	struct ics_irq_state *state;
 	u16 src;
-	bool deliver;
 
 	if (!xics)
 		return -ENODEV;
@@ -144,23 +165,11 @@ int kvmppc_xics_set_xive(struct kvm *kvm, u32 irq, u32 server, u32 priority)
 	if (!icp)
 		return -EINVAL;
 
-	mutex_lock(&ics->lock);
-
 	XICS_DBG("set_xive %#x server %#x prio %#x MP:%d RS:%d\n",
 		 irq, server, priority,
 		 state->masked_pending, state->resend);
 
-	state->server = server;
-	state->priority = priority;
-	deliver = false;
-	if ((state->masked_pending || state->resend) && priority != MASKED) {
-		state->masked_pending = 0;
-		deliver = true;
-	}
-
-	mutex_unlock(&ics->lock);
-
-	if (deliver)
+	if (write_xive(xics, ics, state, server, priority, priority))
 		icp_deliver_irq(xics, icp, irq);
 
 	return 0;
@@ -189,6 +198,53 @@ int kvmppc_xics_get_xive(struct kvm *kvm, u32 irq, u32 *server, u32 *priority)
 	return 0;
 }
 
+int kvmppc_xics_int_on(struct kvm *kvm, u32 irq)
+{
+	struct kvmppc_xics *xics = kvm->arch.xics;
+	struct kvmppc_icp *icp;
+	struct kvmppc_ics *ics;
+	struct ics_irq_state *state;
+	u16 src;
+
+	if (!xics)
+		return -ENODEV;
+
+	ics = kvmppc_xics_find_ics(xics, irq, &src);
+	if (!ics)
+		return -EINVAL;
+	state = &ics->irq_state[src];
+
+	icp = kvmppc_xics_find_server(kvm, state->server);
+	if (!icp)
+		return -EINVAL;
+
+	if (write_xive(xics, ics, state, state->server, state->saved_priority,
+		       state->saved_priority))
+		icp_deliver_irq(xics, icp, irq);
+
+	return 0;
+}
+
+int kvmppc_xics_int_off(struct kvm *kvm, u32 irq)
+{
+	struct kvmppc_xics *xics = kvm->arch.xics;
+	struct kvmppc_ics *ics;
+	struct ics_irq_state *state;
+	u16 src;
+
+	if (!xics)
+		return -ENODEV;
+
+	ics = kvmppc_xics_find_ics(xics, irq, &src);
+	if (!ics)
+		return -EINVAL;
+	state = &ics->irq_state[src];
+
+	write_xive(xics, ics, state, state->server, MASKED, state->priority);
+
+	return 0;
+}
+
 /* -- ICP routines, including hcalls -- */
 
 static inline bool icp_try_update(struct kvmppc_icp *icp,

arch/powerpc/kvm/book3s_xics.h

@@ -36,7 +36,7 @@ struct ics_irq_state {
 	u32 number;
 	u32 server;
 	u8  priority;
-	u8  saved_priority; /* currently unused */
+	u8  saved_priority;
 	u8  resend;
 	u8  masked_pending;
 	u8  asserted; /* Only for LSI */