[RFC PATCH v2 6/6] kvm/ppc/mpic: add KVM_CAP_IRQ_MPIC

[Scott Wood <scottwood@freescale.com>]

Enabling this capability connects the vcpu to the designated in-kernel
MPIC.  Using explicit connections between vcpus and irqchips allows
for flexibility, but the main benefit at the moment is that it
simplifies the code -- KVM doesn't need vm-global state to remember
which MPIC object is associated with this vm, and it doesn't need to
care about ordering between irqchip creation and vcpu creation.

Signed-off-by: Scott Wood <scottwood@freescale.com>
---
 Documentation/virtual/kvm/api.txt   |    8 ++++++
 arch/powerpc/include/asm/kvm_host.h |   10 ++++---
 arch/powerpc/include/asm/kvm_ppc.h  |    2 ++
 arch/powerpc/kvm/booke.c            |    4 ++-
 arch/powerpc/kvm/mpic.c             |   49 +++++++++++++++++++++++++++++++----
 arch/powerpc/kvm/powerpc.c          |   25 +++++++++++++++---
 include/uapi/linux/kvm.h            |    1 +
 7 files changed, 86 insertions(+), 13 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 77328aa..38f9b6d 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2728,3 +2728,11 @@ to receive the topmost interrupt vector.
 When disabled (args[0] = 0), behavior is as if this facility is unsupported.
 
 When this capability is enabled, KVM_EXIT_EPR can occur.
+
+6.6 KVM_CAP_IRQ_MPIC
+
+Architectures: ppc
+Parameters: args[0] is the MPIC device fd
+            args[1] is the MPIC CPU number for this vcpu
+
+This capability connects the vcpu to an in-kernel MPIC device.
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 6713327..2a2e235 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -375,8 +375,10 @@ struct kvmppc_booke_debug_reg {
 	u64 dac[KVMPPC_BOOKE_MAX_DAC];
 };
 
-#define KVMPPC_IRQCHIP_NONE	0
-#define KVMPPC_IRQCHIP_MPIC	1
+#define KVMPPC_IRQ_DEFAULT	0
+#define KVMPPC_IRQ_MPIC		1
+
+struct openpic;
 
 struct kvm_vcpu_arch {
 	ulong host_stack;
@@ -557,8 +559,8 @@ struct kvm_vcpu_arch {
 	unsigned long magic_page_pa; /* phys addr to map the magic page to */
 	unsigned long magic_page_ea; /* effect. addr to map the magic page to */
 
-	int irqchip_type;
-	void *irqchip_priv;
+	int irq_type;		/* one of KVM_IRQ_* */
+	struct openpic *mpic;	/* KVM_IRQ_MPIC */
 
 #ifdef CONFIG_KVM_BOOK3S_64_HV
 	struct kvm_vcpu_arch_shared shregs;
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 20b2a5e..2cc18a4 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -273,6 +273,8 @@ static inline void kvmppc_set_epr(struct kvm_vcpu *vcpu, u32 epr)
 }
 
 void kvmppc_mpic_set_epr(struct kvm_vcpu *vcpu);
+int kvmppc_mpic_connect_vcpu(struct file *mpic_filp, struct kvm_vcpu *vcpu,
+			     u32 cpu);
 
 int kvm_vcpu_ioctl_config_tlb(struct kvm_vcpu *vcpu,
 			      struct kvm_config_tlb *cfg);
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index cddc6b3..7d00222 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -430,8 +430,10 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu,
 		if (update_epr = true) {
 			if (vcpu->arch.epr_flags & KVMPPC_EPR_USER)
 				kvm_make_request(KVM_REQ_EPR_EXIT, vcpu);
-			else if (vcpu->arch.epr_flags & KVMPPC_EPR_KERNEL)
+			else if (vcpu->arch.epr_flags & KVMPPC_EPR_KERNEL) {
+				BUG_ON(vcpu->arch.irq_type != KVMPPC_IRQ_MPIC);
 				kvmppc_mpic_set_epr(vcpu);
+			}
 		}
 
 		new_msr &= msr_mask;
diff --git a/arch/powerpc/kvm/mpic.c b/arch/powerpc/kvm/mpic.c
index 9aace50..b790f47 100644
--- a/arch/powerpc/kvm/mpic.c
+++ b/arch/powerpc/kvm/mpic.c
@@ -1159,7 +1159,7 @@ static uint32_t openpic_iack(struct openpic *opp, struct irq_dest *dst,
 
 void kvmppc_mpic_set_epr(struct kvm_vcpu *vcpu)
 {
-	struct openpic *opp = vcpu->arch.irqchip_priv;
+	struct openpic *opp = vcpu->arch.mpic;
 	int cpu = vcpu->vcpu_id;
 	unsigned long flags;
 
@@ -1442,10 +1442,10 @@ static void map_mmio(struct openpic *opp)
 
 static void unmap_mmio(struct openpic *opp)
 {
-	BUG_ON(opp->mmio_mapped);
-	opp->mmio_mapped = false;
-
-	kvm_io_bus_unregister_dev(opp->kvm, KVM_MMIO_BUS, &opp->mmio);
+	if (opp->mmio_mapped) {
+		opp->mmio_mapped = false;
+		kvm_io_bus_unregister_dev(opp->kvm, KVM_MMIO_BUS, &opp->mmio);
+	}
 }
 
 static int set_base_addr(struct openpic *opp, struct kvm_device_attr *attr)
@@ -1683,6 +1683,45 @@ static const struct file_operations kvm_mpic_fops = {
 	.release = kvm_mpic_release,
 };
 
+int kvmppc_mpic_connect_vcpu(struct file *mpic_filp, struct kvm_vcpu *vcpu,
+			     u32 cpu)
+{
+	struct openpic *opp = mpic_filp->private_data;
+	int ret = 0;
+
+	if (mpic_filp->f_op != &kvm_mpic_fops)
+		return -EPERM;
+	if (opp->kvm != vcpu->kvm)
+		return -EPERM;
+	if (cpu < 0 || cpu >= MAX_CPU)
+		return -EPERM;
+
+	spin_lock_irq(&opp->lock);
+
+	if (opp->dst[cpu].vcpu) {
+		ret = -EEXIST;
+		goto out;
+	}
+	if (vcpu->arch.irq_type) {
+		return -EBUSY;
+		goto out;
+	}
+
+	opp->dst[cpu].vcpu = vcpu;
+	opp->nb_cpus = max(opp->nb_cpus, cpu + 1);
+
+	vcpu->arch.mpic = opp;
+	vcpu->arch.irq_type = KVMPPC_IRQ_MPIC;
+	atomic_inc(&opp->users);
+
+	if (opp->mpic_mode_mask = GCR_MODE_PROXY)
+		vcpu->arch.epr_flags |= KVMPPC_EPR_KERNEL;
+
+out:
+	spin_unlock_irq(&opp->lock);
+	return ret;
+}
+
 int kvm_create_mpic(struct kvm *kvm, u32 type)
 {
 	struct openpic *opp;
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 5656d12..9f67edd 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -25,6 +25,7 @@
 #include <linux/hrtimer.h>
 #include <linux/fs.h>
 #include <linux/slab.h>
+#include <linux/file.h>
 #include <asm/cputable.h>
 #include <asm/uaccess.h>
 #include <asm/kvm_ppc.h>
@@ -327,6 +328,9 @@ int kvm_dev_ioctl_check_extension(long ext)
 #if defined(CONFIG_KVM_E500V2) || defined(CONFIG_KVM_E500MC)
 	case KVM_CAP_SW_TLB:
 #endif
+#ifdef CONFIG_KVM_MPIC
+	case KVM_CAP_IRQ_MPIC:
+#endif
 		r = 1;
 		break;
 	case KVM_CAP_COALESCED_MMIO:
@@ -461,9 +465,9 @@ void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
 
 	kvmppc_remove_vcpu_debugfs(vcpu);
 
-	switch (vcpu->arch.irqchip_type) {
-	case KVMPPC_IRQCHIP_MPIC:
-		mpic_put(vcpu->arch.irqchip_priv);
+	switch (vcpu->arch.irq_type) {
+	case KVMPPC_IRQ_MPIC:
+		mpic_put(vcpu->arch.mpic);
 		break;
 	}
 
@@ -801,6 +805,21 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
 		break;
 	}
 #endif
+#ifdef CONFIG_KVM_MPIC
+	case KVM_CAP_IRQ_MPIC: {
+		struct file *filp;
+
+		r = -EBADF;
+		filp = fget(cap->args[0]);
+		if (!filp)
+			break;
+
+		r = kvmppc_mpic_connect_vcpu(filp, vcpu, cap->args[1]);
+
+		fput(filp);
+		break;
+	}
+#endif
 	default:
 		r = -EINVAL;
 		break;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index d8f44ef..22fce7b 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -669,6 +669,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_ARM_PSCI 87
 #define KVM_CAP_ARM_SET_DEVICE_ADDR 88
 #define KVM_CAP_DEVICE_CTRL 89
+#define KVM_CAP_IRQ_MPIC 90
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
-- 
1.7.9.5