Patchwork [v4,6/6] kvm/ppc/mpic: add KVM_CAP_IRQ_MPIC

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Submitter Scott Wood
Date April 13, 2013, 12:08 a.m.
Message ID <1365811727-24431-7-git-send-email-scottwood@freescale.com>
Download mbox | patch
Permalink /patch/236290/
State New
Headers show

Comments

Scott Wood - April 13, 2013, 12:08 a.m.
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>
---
v4:
- add vcpu->arch.irq_cpu_id, instead of incorrectly using vcpu_id
  now that the numberspaces are separate
- pass the vcpu to mpic code when disconnecting from the vcpu
- minor bugfixes on error paths
---
 Documentation/virtual/kvm/api.txt   |    8 ++++
 arch/powerpc/include/asm/kvm_host.h |    9 ++++
 arch/powerpc/include/asm/kvm_ppc.h  |    4 +-
 arch/powerpc/kvm/booke.c            |    4 ++
 arch/powerpc/kvm/mpic.c             |   82 ++++++++++++++++++++++++++++++++---
 arch/powerpc/kvm/powerpc.c          |   30 +++++++++++++
 include/uapi/linux/kvm.h            |    1 +
 7 files changed, 130 insertions(+), 8 deletions(-)
Paul Mackerras - April 15, 2013, 5:23 a.m.
On Fri, Apr 12, 2013 at 07:08:47PM -0500, Scott Wood wrote:
> 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.

This fails to link with CONFIG_KVM_MPIC=n with the following error:

arch/powerpc/kvm/built-in.o: In function `.kvm_arch_vcpu_free':
(.text+0x94f0): undefined reference to `.kvmppc_mpic_disconnect_vcpu'

Paul.
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Scott Wood - April 15, 2013, 5:52 p.m.
On 04/15/2013 12:23:28 AM, Paul Mackerras wrote:
> On Fri, Apr 12, 2013 at 07:08:47PM -0500, Scott Wood wrote:
> > 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.
> 
> This fails to link with CONFIG_KVM_MPIC=n with the following error:
> 
> arch/powerpc/kvm/built-in.o: In function `.kvm_arch_vcpu_free':
> (.text+0x94f0): undefined reference to `.kvmppc_mpic_disconnect_vcpu'

Sigh, forgot the ifdef again. :-(

-Scott
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Paul Mackerras - April 16, 2013, 3:59 a.m.
On Mon, Apr 15, 2013 at 12:52:27PM -0500, Scott Wood wrote:
> On 04/15/2013 12:23:28 AM, Paul Mackerras wrote:
> >On Fri, Apr 12, 2013 at 07:08:47PM -0500, Scott Wood wrote:
> >> 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.
> >
> >This fails to link with CONFIG_KVM_MPIC=n with the following error:
> >
> >arch/powerpc/kvm/built-in.o: In function `.kvm_arch_vcpu_free':
> >(.text+0x94f0): undefined reference to `.kvmppc_mpic_disconnect_vcpu'
> 
> Sigh, forgot the ifdef again. :-(

Or you could define an empty static inline function in the
CONFIG_KVM_MPIC=n case, which looks a little nicer at the point of
use.

Paul.
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Patch

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index d52f3f9..4c326ae 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 7e7aef9..36368c9 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -375,6 +375,11 @@  struct kvmppc_booke_debug_reg {
 	u64 dac[KVMPPC_BOOKE_MAX_DAC];
 };
 
+#define KVMPPC_IRQ_DEFAULT	0
+#define KVMPPC_IRQ_MPIC		1
+
+struct openpic;
+
 struct kvm_vcpu_arch {
 	ulong host_stack;
 	u32 host_pid;
@@ -554,6 +559,10 @@  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 irq_type;		/* one of KVM_IRQ_* */
+	int irq_cpu_id;
+	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 3b63b97..b25d475 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -248,7 +248,6 @@  int kvmppc_set_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *);
 void kvmppc_set_pid(struct kvm_vcpu *vcpu, u32 pid);
 
 struct openpic;
-void kvmppc_mpic_put(struct openpic *opp);
 
 #ifdef CONFIG_KVM_BOOK3S_64_HV
 static inline void kvmppc_set_xics_phys(int cpu, unsigned long addr)
@@ -276,6 +275,9 @@  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 kvm_device *dev, struct kvm_vcpu *vcpu,
+			     u32 cpu);
+void kvmppc_mpic_disconnect_vcpu(struct openpic *opp, struct kvm_vcpu *vcpu);
 
 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 cff53d4..0097912 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -430,6 +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) {
+				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 8ed4072..a231e0c 100644
--- a/arch/powerpc/kvm/mpic.c
+++ b/arch/powerpc/kvm/mpic.c
@@ -114,7 +114,7 @@  static struct fsl_mpic_info fsl_mpic_42 = {
 static int get_current_cpu(void)
 {
 	struct kvm_vcpu *vcpu = current->thread.kvm_vcpu;
-	return vcpu ? vcpu->vcpu_id : -1;
+	return vcpu ? vcpu->arch.irq_cpu_id : -1;
 }
 
 static int openpic_cpu_write_internal(void *opaque, gpa_t addr,
@@ -244,7 +244,7 @@  static void mpic_irq_raise(struct openpic *opp, struct irq_dest *dst,
 		return;
 	}
 
-	pr_debug("%s: cpu %d output %d\n", __func__, dst->vcpu->vcpu_id,
+	pr_debug("%s: cpu %d output %d\n", __func__, dst->vcpu->arch.irq_cpu_id,
 		output);
 
 	if (output != ILR_INTTGT_INT)	/* TODO */
@@ -262,7 +262,7 @@  static void mpic_irq_lower(struct openpic *opp, struct irq_dest *dst,
 		return;
 	}
 
-	pr_debug("%s: cpu %d output %d\n", __func__, dst->vcpu->vcpu_id,
+	pr_debug("%s: cpu %d output %d\n", __func__, dst->vcpu->arch.irq_cpu_id,
 		output);
 
 	if (output != ILR_INTTGT_INT)	/* TODO */
@@ -1160,6 +1160,20 @@  static uint32_t openpic_iack(struct openpic *opp, struct irq_dest *dst,
 	return retval;
 }
 
+void kvmppc_mpic_set_epr(struct kvm_vcpu *vcpu)
+{
+	struct openpic *opp = vcpu->arch.mpic;
+	int cpu = vcpu->arch.irq_cpu_id;
+	unsigned long flags;
+
+	spin_lock_irqsave(&opp->lock, flags);
+
+	if ((opp->gcr & opp->mpic_mode_mask) == GCR_MODE_PROXY)
+		kvmppc_set_epr(vcpu, openpic_iack(opp, &opp->dst[cpu], cpu));
+
+	spin_unlock_irqrestore(&opp->lock, flags);
+}
+
 static int openpic_cpu_read_internal(void *opaque, gpa_t addr,
 				     u32 *ptr, int idx)
 {
@@ -1426,10 +1440,10 @@  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)
@@ -1688,3 +1702,57 @@  struct kvm_device_ops kvm_mpic_ops = {
 	.get_attr = mpic_get_attr,
 	.has_attr = mpic_has_attr,
 };
+
+int kvmppc_mpic_connect_vcpu(struct kvm_device *dev, struct kvm_vcpu *vcpu,
+			     u32 cpu)
+{
+	struct openpic *opp = dev->private;
+	int ret = 0;
+
+	if (dev->ops != &kvm_mpic_ops)
+		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) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	opp->dst[cpu].vcpu = vcpu;
+	opp->nb_cpus = max(opp->nb_cpus, cpu + 1);
+
+	vcpu->arch.mpic = opp;
+	vcpu->arch.irq_cpu_id = cpu;
+	vcpu->arch.irq_type = KVMPPC_IRQ_MPIC;
+
+	/* This might need to be changed if GCR gets extended */
+	if (opp->mpic_mode_mask == GCR_MODE_PROXY)
+		vcpu->arch.epr_flags |= KVMPPC_EPR_KERNEL;
+
+	kvm_device_get(dev);
+out:
+	spin_unlock_irq(&opp->lock);
+	return ret;
+}
+
+/*
+ * This should only happen immediately before the mpic is destroyed,
+ * so we shouldn't need to worry about anything still trying to
+ * access the vcpu pointer.
+ */
+void kvmppc_mpic_disconnect_vcpu(struct openpic *opp, struct kvm_vcpu *vcpu)
+{
+	BUG_ON(!opp->dst[vcpu->arch.irq_cpu_id].vcpu);
+
+	opp->dst[vcpu->arch.irq_cpu_id].vcpu = NULL;
+	kvm_device_put(opp->dev);
+}
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index c9a2972..1d3888b 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:
@@ -460,6 +464,13 @@  void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
 	tasklet_kill(&vcpu->arch.tasklet);
 
 	kvmppc_remove_vcpu_debugfs(vcpu);
+
+	switch (vcpu->arch.irq_type) {
+	case KVMPPC_IRQ_MPIC:
+		kvmppc_mpic_disconnect_vcpu(vcpu->arch.mpic, vcpu);
+		break;
+	}
+
 	kvmppc_core_vcpu_free(vcpu);
 }
 
@@ -794,6 +805,25 @@  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;
+		struct kvm_device *dev;
+
+		r = -EBADF;
+		filp = fget(cap->args[0]);
+		if (!filp)
+			break;
+
+		r = -EPERM;
+		dev = kvm_device_from_filp(filp);
+		if (dev)
+			r = kvmppc_mpic_connect_vcpu(dev, 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 76963ec..5b3248a 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