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Commit 816c7667 authored by Jens Freimann's avatar Jens Freimann Committed by Christian Borntraeger
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KVM: s390: migrate vcpu interrupt state 



This patch adds support to migrate vcpu interrupts. Two new vcpu ioctls
are added which get/set the complete status of pending interrupts in one
go. The ioctls are marked as available with the new capability
KVM_CAP_S390_IRQ_STATE.

We can not use a ONEREG, as the number of pending local interrupts is not
constant and depends on the number of CPUs.

To retrieve the interrupt state we add an ioctl KVM_S390_GET_IRQ_STATE.
Its input parameter is a pointer to a struct kvm_s390_irq_state which
has a buffer and length.  For all currently pending interrupts, we copy
a struct kvm_s390_irq into the buffer and pass it to userspace.

To store interrupt state into a buffer provided by userspace, we add an
ioctl KVM_S390_SET_IRQ_STATE. It passes a struct kvm_s390_irq_state into
the kernel and injects all interrupts contained in the buffer.

Signed-off-by: default avatarJens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
parent 79e87a10

Documentation/virtual/kvm/api.txt

+61 −0
Original line number Diff line number Diff line
@@ -2875,6 +2875,67 @@ KVM_S390_MCHK - machine check interrupt; parameters in .mchk 


Note that the vcpu ioctl is asynchronous to vcpu execution.



4.94 KVM_S390_GET_IRQ_STATE



Capability: KVM_CAP_S390_IRQ_STATE

Architectures: s390

Type: vcpu ioctl

Parameters: struct kvm_s390_irq_state (out)

Returns: >= number of bytes copied into buffer,

         -EINVAL if buffer size is 0,

         -ENOBUFS if buffer size is too small to fit all pending interrupts,

         -EFAULT if the buffer address was invalid



This ioctl allows userspace to retrieve the complete state of all currently

pending interrupts in a single buffer. Use cases include migration

and introspection. The parameter structure contains the address of a

userspace buffer and its length:



struct kvm_s390_irq_state {

	__u64 buf;

	__u32 flags;

	__u32 len;

	__u32 reserved[4];

};



Userspace passes in the above struct and for each pending interrupt a

struct kvm_s390_irq is copied to the provided buffer.



If -ENOBUFS is returned the buffer provided was too small and userspace

may retry with a bigger buffer.



4.95 KVM_S390_SET_IRQ_STATE



Capability: KVM_CAP_S390_IRQ_STATE

Architectures: s390

Type: vcpu ioctl

Parameters: struct kvm_s390_irq_state (in)

Returns: 0 on success,

         -EFAULT if the buffer address was invalid,

         -EINVAL for an invalid buffer length (see below),

         -EBUSY if there were already interrupts pending,

         errors occurring when actually injecting the

          interrupt. See KVM_S390_IRQ.



This ioctl allows userspace to set the complete state of all cpu-local

interrupts currently pending for the vcpu. It is intended for restoring

interrupt state after a migration. The input parameter is a userspace buffer

containing a struct kvm_s390_irq_state:



struct kvm_s390_irq_state {

	__u64 buf;

	__u32 len;

	__u32 pad;

};



The userspace memory referenced by buf contains a struct kvm_s390_irq

for each interrupt to be injected into the guest.

If one of the interrupts could not be injected for some reason the

ioctl aborts.



len must be a multiple of sizeof(struct kvm_s390_irq). It must be > 0

and it must not exceed (max_vcpus + 32) * sizeof(struct kvm_s390_irq),

which is the maximum number of possibly pending cpu-local interrupts.



5. The kvm_run structure

------------------------

arch/s390/kvm/interrupt.c

+140 −0
Original line number Diff line number Diff line
@@ -2123,3 +2123,143 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm, 
{

	return -EINVAL;

}



int kvm_s390_set_irq_state(struct kvm_vcpu *vcpu, void __user *irqstate, int len)

{

	struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;

	struct kvm_s390_irq *buf;

	int r = 0;

	int n;



	buf = vmalloc(len);

	if (!buf)

		return -ENOMEM;



	if (copy_from_user((void *) buf, irqstate, len)) {

		r = -EFAULT;

		goto out_free;

	}



	/*

	 * Don't allow setting the interrupt state

	 * when there are already interrupts pending

	 */

	spin_lock(&li->lock);

	if (li->pending_irqs) {

		r = -EBUSY;

		goto out_unlock;

	}



	for (n = 0; n < len / sizeof(*buf); n++) {

		r = do_inject_vcpu(vcpu, &buf[n]);

		if (r)

			break;

	}



out_unlock:

	spin_unlock(&li->lock);

out_free:

	vfree(buf);



	return r;

}



static void store_local_irq(struct kvm_s390_local_interrupt *li,

			    struct kvm_s390_irq *irq,

			    unsigned long irq_type)

{

	switch (irq_type) {

	case IRQ_PEND_MCHK_EX:

	case IRQ_PEND_MCHK_REP:

		irq->type = KVM_S390_MCHK;

		irq->u.mchk = li->irq.mchk;

		break;

	case IRQ_PEND_PROG:

		irq->type = KVM_S390_PROGRAM_INT;

		irq->u.pgm = li->irq.pgm;

		break;

	case IRQ_PEND_PFAULT_INIT:

		irq->type = KVM_S390_INT_PFAULT_INIT;

		irq->u.ext = li->irq.ext;

		break;

	case IRQ_PEND_EXT_EXTERNAL:

		irq->type = KVM_S390_INT_EXTERNAL_CALL;

		irq->u.extcall = li->irq.extcall;

		break;

	case IRQ_PEND_EXT_CLOCK_COMP:

		irq->type = KVM_S390_INT_CLOCK_COMP;

		break;

	case IRQ_PEND_EXT_CPU_TIMER:

		irq->type = KVM_S390_INT_CPU_TIMER;

		break;

	case IRQ_PEND_SIGP_STOP:

		irq->type = KVM_S390_SIGP_STOP;

		irq->u.stop = li->irq.stop;

		break;

	case IRQ_PEND_RESTART:

		irq->type = KVM_S390_RESTART;

		break;

	case IRQ_PEND_SET_PREFIX:

		irq->type = KVM_S390_SIGP_SET_PREFIX;

		irq->u.prefix = li->irq.prefix;

		break;

	}

}



int kvm_s390_get_irq_state(struct kvm_vcpu *vcpu, __u8 __user *buf, int len)

{

	uint8_t sigp_ctrl = vcpu->kvm->arch.sca->cpu[vcpu->vcpu_id].sigp_ctrl;

	unsigned long sigp_emerg_pending[BITS_TO_LONGS(KVM_MAX_VCPUS)];

	struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;

	unsigned long pending_irqs;

	struct kvm_s390_irq irq;

	unsigned long irq_type;

	int cpuaddr;

	int n = 0;



	spin_lock(&li->lock);

	pending_irqs = li->pending_irqs;

	memcpy(&sigp_emerg_pending, &li->sigp_emerg_pending,

	       sizeof(sigp_emerg_pending));

	spin_unlock(&li->lock);



	for_each_set_bit(irq_type, &pending_irqs, IRQ_PEND_COUNT) {

		memset(&irq, 0, sizeof(irq));

		if (irq_type == IRQ_PEND_EXT_EMERGENCY)

			continue;

		if (n + sizeof(irq) > len)

			return -ENOBUFS;

		store_local_irq(&vcpu->arch.local_int, &irq, irq_type);

		if (copy_to_user(&buf[n], &irq, sizeof(irq)))

			return -EFAULT;

		n += sizeof(irq);

	}



	if (test_bit(IRQ_PEND_EXT_EMERGENCY, &pending_irqs)) {

		for_each_set_bit(cpuaddr, sigp_emerg_pending, KVM_MAX_VCPUS) {

			memset(&irq, 0, sizeof(irq));

			if (n + sizeof(irq) > len)

				return -ENOBUFS;

			irq.type = KVM_S390_INT_EMERGENCY;

			irq.u.emerg.code = cpuaddr;

			if (copy_to_user(&buf[n], &irq, sizeof(irq)))

				return -EFAULT;

			n += sizeof(irq);

		}

	}



	if ((sigp_ctrl & SIGP_CTRL_C) &&

	    (atomic_read(&vcpu->arch.sie_block->cpuflags) &

	     CPUSTAT_ECALL_PEND)) {

		if (n + sizeof(irq) > len)

			return -ENOBUFS;

		memset(&irq, 0, sizeof(irq));

		irq.type = KVM_S390_INT_EXTERNAL_CALL;

		irq.u.extcall.code = sigp_ctrl & SIGP_CTRL_SCN_MASK;

		if (copy_to_user(&buf[n], &irq, sizeof(irq)))

			return -EFAULT;

		n += sizeof(irq);

	}



	return n;

}

arch/s390/kvm/kvm-s390.c

+36 −0
Original line number Diff line number Diff line
@@ -41,6 +41,9 @@ 
#include "trace-s390.h"



#define MEM_OP_MAX_SIZE 65536	/* Maximum transfer size for KVM_S390_MEM_OP */

#define LOCAL_IRQS 32

#define VCPU_IRQS_MAX_BUF (sizeof(struct kvm_s390_irq) * \

			   (KVM_MAX_VCPUS + LOCAL_IRQS))



#define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
@@ -181,6 +184,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) 
	case KVM_CAP_S390_USER_SIGP:

	case KVM_CAP_S390_USER_STSI:

	case KVM_CAP_S390_SKEYS:

	case KVM_CAP_S390_IRQ_STATE:

		r = 1;

		break;

	case KVM_CAP_S390_MEM_OP:
@@ -2500,6 +2504,38 @@ long kvm_arch_vcpu_ioctl(struct file *filp, 
			r = -EFAULT;

		break;

	}

	case KVM_S390_SET_IRQ_STATE: {

		struct kvm_s390_irq_state irq_state;



		r = -EFAULT;

		if (copy_from_user(&irq_state, argp, sizeof(irq_state)))

			break;

		if (irq_state.len > VCPU_IRQS_MAX_BUF ||

		    irq_state.len == 0 ||

		    irq_state.len % sizeof(struct kvm_s390_irq) > 0) {

			r = -EINVAL;

			break;

		}

		r = kvm_s390_set_irq_state(vcpu,

					   (void __user *) irq_state.buf,

					   irq_state.len);

		break;

	}

	case KVM_S390_GET_IRQ_STATE: {

		struct kvm_s390_irq_state irq_state;



		r = -EFAULT;

		if (copy_from_user(&irq_state, argp, sizeof(irq_state)))

			break;

		if (irq_state.len == 0) {

			r = -EINVAL;

			break;

		}

		r = kvm_s390_get_irq_state(vcpu,

					   (__u8 __user *)  irq_state.buf,

					   irq_state.len);

		break;

	}

	default:

		r = -ENOTTY;

	}

arch/s390/kvm/kvm-s390.h

+4 −0
Original line number Diff line number Diff line
@@ -272,6 +272,10 @@ int kvm_s390_ext_call_pending(struct kvm_vcpu *vcpu); 
extern struct kvm_device_ops kvm_flic_ops;

int kvm_s390_is_stop_irq_pending(struct kvm_vcpu *vcpu);

void kvm_s390_clear_stop_irq(struct kvm_vcpu *vcpu);

int kvm_s390_set_irq_state(struct kvm_vcpu *vcpu,

			   void __user *buf, int len);

int kvm_s390_get_irq_state(struct kvm_vcpu *vcpu,

			   __u8 __user *buf, int len);



/* implemented in guestdbg.c */

void kvm_s390_backup_guest_per_regs(struct kvm_vcpu *vcpu);

include/uapi/linux/kvm.h

+11 −0
Original line number Diff line number Diff line
@@ -558,6 +558,13 @@ struct kvm_s390_irq { 
	} u;

};



struct kvm_s390_irq_state {

	__u64 buf;

	__u32 flags;

	__u32 len;

	__u32 reserved[4];

};



/* for KVM_SET_GUEST_DEBUG */



#define KVM_GUESTDBG_ENABLE		0x00000001
@@ -803,6 +810,7 @@ struct kvm_ppc_smmu_info { 
#define KVM_CAP_S390_USER_STSI 109

#define KVM_CAP_S390_SKEYS 110

#define KVM_CAP_S390_INJECT_IRQ 113

#define KVM_CAP_S390_IRQ_STATE 114



#ifdef KVM_CAP_IRQ_ROUTING
@@ -1185,6 +1193,9 @@ struct kvm_s390_ucas_mapping { 
#define KVM_S390_SET_SKEYS      _IOW(KVMIO, 0xb3, struct kvm_s390_skeys)

/* Available with KVM_CAP_S390_INJECT_IRQ */

#define KVM_S390_IRQ              _IOW(KVMIO,  0xb4, struct kvm_s390_irq)

/* Available with KVM_CAP_S390_IRQ_STATE */

#define KVM_S390_SET_IRQ_STATE	  _IOW(KVMIO, 0xb5, struct kvm_s390_irq_state)

#define KVM_S390_GET_IRQ_STATE	  _IOW(KVMIO, 0xb6, struct kvm_s390_irq_state)



#define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)

#define KVM_DEV_ASSIGN_PCI_2_3		(1 << 1)