Commit 6352e4d2 authored by David Hildenbrand's avatar David Hildenbrand Committed by Christian Borntraeger
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KVM: s390: implement KVM_(S|G)ET_MP_STATE for user space state control 



This patch
- adds s390 specific MP states to linux headers and documents them
- implements the KVM_{SET,GET}_MP_STATE ioctls
- enables KVM_CAP_MP_STATE
- allows user space to control the VCPU state on s390.

If user space sets the VCPU state using the ioctl KVM_SET_MP_STATE, we can disable
manual changing of the VCPU state and trust user space to do the right thing.

Signed-off-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 0b4820d6

Documentation/virtual/kvm/api.txt

+8 −2
Original line number Diff line number Diff line
@@ -974,7 +974,7 @@ for vm-wide capabilities. 
4.38 KVM_GET_MP_STATE



Capability: KVM_CAP_MP_STATE

Architectures: x86, ia64

Architectures: x86, ia64, s390

Type: vcpu ioctl

Parameters: struct kvm_mp_state (out)

Returns: 0 on success; -1 on error
@@ -998,6 +998,12 @@ Possible values are: 
                                 is waiting for an interrupt [x86, ia64]

 - KVM_MP_STATE_SIPI_RECEIVED:   the vcpu has just received a SIPI (vector

                                 accessible via KVM_GET_VCPU_EVENTS) [x86, ia64]

 - KVM_MP_STATE_STOPPED:         the vcpu is stopped [s390]

 - KVM_MP_STATE_CHECK_STOP:      the vcpu is in a special error state [s390]

 - KVM_MP_STATE_OPERATING:       the vcpu is operating (running or halted)

                                 [s390]

 - KVM_MP_STATE_LOAD:            the vcpu is in a special load/startup state

                                 [s390]



On x86 and ia64, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an

in-kernel irqchip, the multiprocessing state must be maintained by userspace on
@@ -1007,7 +1013,7 @@ these architectures. 
4.39 KVM_SET_MP_STATE



Capability: KVM_CAP_MP_STATE

Architectures: x86, ia64

Architectures: x86, ia64, s390

Type: vcpu ioctl

Parameters: struct kvm_mp_state (in)

Returns: 0 on success; -1 on error

arch/s390/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -418,6 +418,7 @@ struct kvm_arch{ 
	int css_support;

	int use_irqchip;

	int use_cmma;

	int user_cpu_state_ctrl;

	struct s390_io_adapter *adapters[MAX_S390_IO_ADAPTERS];

	wait_queue_head_t ipte_wq;

	spinlock_t start_stop_lock;

arch/s390/kvm/diag.c

+2 −1
Original line number Diff line number Diff line
@@ -176,6 +176,7 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu) 
		return -EOPNOTSUPP;

	}



	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))

		kvm_s390_vcpu_stop(vcpu);

	vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM;

	vcpu->run->s390_reset_flags |= KVM_S390_RESET_IPL;

arch/s390/kvm/intercept.c

+2 −1
Original line number Diff line number Diff line
@@ -73,6 +73,7 @@ static int handle_stop(struct kvm_vcpu *vcpu) 
			return rc;

	}



	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))

		kvm_s390_vcpu_stop(vcpu);

	return -EOPNOTSUPP;

}

arch/s390/kvm/kvm-s390.c

+33 −4
Original line number Diff line number Diff line
@@ -167,6 +167,7 @@ int kvm_dev_ioctl_check_extension(long ext) 
	case KVM_CAP_DEVICE_CTRL:

	case KVM_CAP_ENABLE_CAP_VM:

	case KVM_CAP_VM_ATTRIBUTES:

	case KVM_CAP_MP_STATE:

		r = 1;

		break;

	case KVM_CAP_NR_VCPUS:
@@ -595,6 +596,7 @@ static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu) 
	vcpu->arch.sie_block->pp = 0;

	vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;

	kvm_clear_async_pf_completion_queue(vcpu);

	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))

		kvm_s390_vcpu_stop(vcpu);

	kvm_s390_clear_local_irqs(vcpu);

}
@@ -980,13 +982,34 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, 
int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,

				    struct kvm_mp_state *mp_state)

{

	return -EINVAL; /* not implemented yet */

	/* CHECK_STOP and LOAD are not supported yet */

	return is_vcpu_stopped(vcpu) ? KVM_MP_STATE_STOPPED :

				       KVM_MP_STATE_OPERATING;

}



int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,

				    struct kvm_mp_state *mp_state)

{

	return -EINVAL; /* not implemented yet */

	int rc = 0;



	/* user space knows about this interface - let it control the state */

	vcpu->kvm->arch.user_cpu_state_ctrl = 1;



	switch (mp_state->mp_state) {

	case KVM_MP_STATE_STOPPED:

		kvm_s390_vcpu_stop(vcpu);

		break;

	case KVM_MP_STATE_OPERATING:

		kvm_s390_vcpu_start(vcpu);

		break;

	case KVM_MP_STATE_LOAD:

	case KVM_MP_STATE_CHECK_STOP:

		/* fall through - CHECK_STOP and LOAD are not supported yet */

	default:

		rc = -ENXIO;

	}



	return rc;

}



bool kvm_s390_cmma_enabled(struct kvm *kvm)
@@ -1284,7 +1307,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
	if (vcpu->sigset_active)

		sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);



	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm)) {

		kvm_s390_vcpu_start(vcpu);

	} else if (is_vcpu_stopped(vcpu)) {

		pr_err_ratelimited("kvm-s390: can't run stopped vcpu %d\n",

				   vcpu->vcpu_id);

		return -EINVAL;

	}



	switch (kvm_run->exit_reason) {

	case KVM_EXIT_S390_SIEIC:

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