Patchwork [2/2] KVM: PPC: Book3S: Add IRQFD support for in-kernel XICS

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Submitter Paul Mackerras
Date Sept. 17, 2013, 9:20 a.m.
Message ID <20130917092005.GB12722@iris.ozlabs.ibm.com>
Download mbox | patch
Permalink /patch/275412/
State New
Headers show

Comments

Paul Mackerras - Sept. 17, 2013, 9:20 a.m.
This adds support for using IRQFD with the in-kernel XICS emulation.
To do this, we have to tie the XICS in to the generic IRQ routing
infrastructure, meaning that we now have a xics_set_irq() function
and we use the generic kvm_set_irq() instead of defining our own.
We do not support emulated MSIs at this stage.  The level argument to
xics_set_irq can be 0 or 1, or can be one of the powerpc-specific
values KVM_INTERRUPT_SET, KVM_INTERRUPT_UNSET or
KVM_INTERRUPT_SET_LEVEL.

This also removes the `report_status' argument to ics_deliver_irq()
since it is always false, given that we don't support
KVM_IRQ_LINE_STATUS.

We also have to arrange to call kvm_notify_acked_irq() when an
interrupt has been processed, that is, when the guest does the H_EOI
hypercall.  If we are processing the XICS hypercalls in real mode then
we need to exit the guest to do that call.

Signed-off-by: Paul Mackerras <paulus@samba.org>
---
 arch/powerpc/kvm/Kconfig             |  2 +
 arch/powerpc/kvm/book3s_hv_rm_xics.c |  6 +++
 arch/powerpc/kvm/book3s_xics.c       | 80 ++++++++++++++++++++++++++++--------
 arch/powerpc/kvm/book3s_xics.h       |  2 +
 4 files changed, 74 insertions(+), 16 deletions(-)

Patch

diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index ffaef2c..7bbb9c0 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -167,6 +167,8 @@  config KVM_MPIC
 config KVM_XICS
 	bool "KVM in-kernel XICS emulation"
 	depends on KVM_BOOK3S_64 && !KVM_MPIC
+	select HAVE_KVM_IRQCHIP
+	select HAVE_KVM_IRQ_ROUTING
 	---help---
 	  Include support for the XICS (eXternal Interrupt Controller
 	  Specification) interrupt controller architecture used on
diff --git a/arch/powerpc/kvm/book3s_hv_rm_xics.c b/arch/powerpc/kvm/book3s_hv_rm_xics.c
index b4b0082..d3eb4bd 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_xics.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_xics.c
@@ -401,6 +401,12 @@  int kvmppc_rm_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr)
 		icp->rm_action |= XICS_RM_REJECT;
 		icp->rm_reject = irq;
 	}
+
+	if (!hlist_empty(&vcpu->kvm->irq_ack_notifier_list)) {
+		icp->rm_action |= XICS_RM_NOTIFY_EOI;
+		icp->rm_eoied_irq = irq;
+	}
+
  bail:
 	return check_too_hard(xics, icp);
 }
diff --git a/arch/powerpc/kvm/book3s_xics.c b/arch/powerpc/kvm/book3s_xics.c
index a3a5cb8..324da28 100644
--- a/arch/powerpc/kvm/book3s_xics.c
+++ b/arch/powerpc/kvm/book3s_xics.c
@@ -35,6 +35,10 @@ 
 #define ENABLE_REALMODE	true
 #define DEBUG_REALMODE	false
 
+static int xics_set_irq(struct kvm_kernel_irq_routing_entry *e,
+			struct kvm *kvm, int irq_source_id, int level,
+			bool line_status);
+
 /*
  * LOCKING
  * =======
@@ -64,8 +68,7 @@ 
 static void icp_deliver_irq(struct kvmppc_xics *xics, struct kvmppc_icp *icp,
 			    u32 new_irq);
 
-static int ics_deliver_irq(struct kvmppc_xics *xics, u32 irq, u32 level,
-			   bool report_status)
+static int ics_deliver_irq(struct kvmppc_xics *xics, u32 irq, u32 level)
 {
 	struct ics_irq_state *state;
 	struct kvmppc_ics *ics;
@@ -82,17 +85,14 @@  static int ics_deliver_irq(struct kvmppc_xics *xics, u32 irq, u32 level,
 	if (!state->exists)
 		return -EINVAL;
 
-	if (report_status)
-		return state->asserted;
-
 	/*
 	 * We set state->asserted locklessly. This should be fine as
 	 * we are the only setter, thus concurrent access is undefined
 	 * to begin with.
 	 */
-	if (level == KVM_INTERRUPT_SET_LEVEL)
+	if (level == 1 || level == KVM_INTERRUPT_SET_LEVEL)
 		state->asserted = 1;
-	else if (level == KVM_INTERRUPT_UNSET) {
+	else if (level == 0 || level == KVM_INTERRUPT_UNSET) {
 		state->asserted = 0;
 		return 0;
 	}
@@ -100,7 +100,7 @@  static int ics_deliver_irq(struct kvmppc_xics *xics, u32 irq, u32 level,
 	/* Attempt delivery */
 	icp_deliver_irq(xics, NULL, irq);
 
-	return state->asserted;
+	return 0;
 }
 
 static void ics_check_resend(struct kvmppc_xics *xics, struct kvmppc_ics *ics,
@@ -772,6 +772,8 @@  static noinline int kvmppc_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr)
 	if (state->asserted)
 		icp_deliver_irq(xics, icp, irq);
 
+	kvm_notify_acked_irq(vcpu->kvm, 0, irq);
+
 	return H_SUCCESS;
 }
 
@@ -789,6 +791,8 @@  static noinline int kvmppc_xics_rm_complete(struct kvm_vcpu *vcpu, u32 hcall)
 		icp_check_resend(xics, icp);
 	if (icp->rm_action & XICS_RM_REJECT)
 		icp_deliver_irq(xics, icp, icp->rm_reject);
+	if (icp->rm_action & XICS_RM_NOTIFY_EOI)
+		kvm_notify_acked_irq(vcpu->kvm, 0, icp->rm_eoied_irq);
 
 	icp->rm_action = 0;
 
@@ -1164,14 +1168,6 @@  static int xics_set_source(struct kvmppc_xics *xics, long irq, u64 addr)
 	return 0;
 }
 
-int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
-		bool line_status)
-{
-	struct kvmppc_xics *xics = kvm->arch.xics;
-
-	return ics_deliver_irq(xics, irq, level, line_status);
-}
-
 static int xics_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
 {
 	struct kvmppc_xics *xics = dev->private;
@@ -1248,6 +1244,10 @@  static int kvmppc_xics_create(struct kvm_device *dev, u32 type)
 	if (ret)
 		return ret;
 
+	kvm->default_irq_route.type = KVM_IRQ_ROUTING_IRQCHIP;
+	kvm->default_irq_route.set = xics_set_irq;
+	kvm->default_irq_route.irqchip.irqchip = 0;
+
 	xics_debugfs_init(xics);
 
 #ifdef CONFIG_KVM_BOOK3S_64_HV
@@ -1298,3 +1298,51 @@  void kvmppc_xics_free_icp(struct kvm_vcpu *vcpu)
 	vcpu->arch.icp = NULL;
 	vcpu->arch.irq_type = KVMPPC_IRQ_DEFAULT;
 }
+
+/*
+ * Return value ideally indicates how the interrupt was handled, but no
+ * callers look at it (given that we don't implement KVM_IRQ_LINE_STATUS),
+ * so just return 0.
+ */
+static int xics_set_irq(struct kvm_kernel_irq_routing_entry *e,
+			struct kvm *kvm, int irq_source_id, int level,
+			bool line_status)
+{
+	struct kvmppc_xics *xics = kvm->arch.xics;
+	u32 irq = e->irqchip.pin;
+
+	return ics_deliver_irq(xics, irq, level);
+}
+
+int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
+		struct kvm *kvm, int irq_source_id, int level, bool line_status)
+{
+	return -EINVAL;
+}
+
+int kvm_set_routing_entry(struct kvm_irq_routing_table *rt,
+			  struct kvm_kernel_irq_routing_entry *e,
+			  const struct kvm_irq_routing_entry *ue)
+{
+	int r = -EINVAL;
+
+	switch (ue->type) {
+	case KVM_IRQ_ROUTING_IRQCHIP:
+		e->set = xics_set_irq;
+		e->irqchip.irqchip = ue->u.irqchip.irqchip;
+		e->irqchip.pin = ue->u.irqchip.pin;
+		if (e->irqchip.pin >= KVM_IRQCHIP_NUM_PINS)
+			goto out;
+		rt->chip[ue->u.irqchip.irqchip][e->irqchip.pin] = ue->gsi;
+		break;
+	case KVM_IRQ_ROUTING_MSI:
+		/* No MSI support for now */
+		goto out;
+	default:
+		goto out;
+	}
+
+	r = 0;
+out:
+	return r;
+}
diff --git a/arch/powerpc/kvm/book3s_xics.h b/arch/powerpc/kvm/book3s_xics.h
index dd9326c..e8aaa7a 100644
--- a/arch/powerpc/kvm/book3s_xics.h
+++ b/arch/powerpc/kvm/book3s_xics.h
@@ -71,9 +71,11 @@  struct kvmppc_icp {
 #define XICS_RM_KICK_VCPU	0x1
 #define XICS_RM_CHECK_RESEND	0x2
 #define XICS_RM_REJECT		0x4
+#define XICS_RM_NOTIFY_EOI	0x8
 	u32 rm_action;
 	struct kvm_vcpu *rm_kick_target;
 	u32  rm_reject;
+	u32  rm_eoied_irq;
 
 	/* Debug stuff for real mode */
 	union kvmppc_icp_state rm_dbgstate;