Commit da9a1446 authored by Christian Borntraeger's avatar Christian Borntraeger
Browse files

KVM: s390: provide a capability for AIS state migration 



The AIS capability was introduced in 4.12, while the interface to
migrate the state was added in 4.13. Unfortunately it is not possible
for userspace to detect the migration capability without creating a flic
kvm device. As in QEMU the cpu model detection runs on the "none"
machine this will result in cpu model issues regarding the "ais"
capability.

To get the "ais" capability properly let's add a new KVM capability that
tells userspace that AIS states can be migrated.

Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Acked-by: default avatarHalil Pasic <pasic@linux.vnet.ibm.com>
parent 4dd6f17e

Documentation/virtual/kvm/api.txt

+9 −0
Original line number Diff line number Diff line
@@ -4347,3 +4347,12 @@ This capability indicates that userspace can load HV_X64_MSR_VP_INDEX msr. Its 
value is used to denote the target vcpu for a SynIC interrupt.  For

compatibilty, KVM initializes this msr to KVM's internal vcpu index.  When this

capability is absent, userspace can still query this msr's value.



8.13 KVM_CAP_S390_AIS_MIGRATION



Architectures: s390

Parameters: none



This capability indicates if the flic device will be able to get/set the

AIS states for migration via the KVM_DEV_FLIC_AISM_ALL attribute and allows

to discover this without having to create a flic device.

Documentation/virtual/kvm/devices/s390_flic.txt

+2 −0
Original line number Diff line number Diff line
@@ -151,6 +151,8 @@ struct kvm_s390_ais_all { 
    to an ISC (MSB0 bit 0 to ISC 0 and so on). The combination of simm bit and

    nimm bit presents AIS mode for a ISC.



    KVM_DEV_FLIC_AISM_ALL is indicated by KVM_CAP_S390_AIS_MIGRATION.



Note: The KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR device ioctls executed on

FLIC with an unknown group or attribute gives the error code EINVAL (instead of

ENXIO, as specified in the API documentation). It is not possible to conclude

arch/s390/kvm/kvm-s390.c

+1 −0
Original line number Diff line number Diff line
@@ -395,6 +395,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) 
	case KVM_CAP_S390_USER_INSTR0:

	case KVM_CAP_S390_CMMA_MIGRATION:

	case KVM_CAP_S390_AIS:

	case KVM_CAP_S390_AIS_MIGRATION:

		r = 1;

		break;

	case KVM_CAP_S390_MEM_OP:

include/uapi/linux/kvm.h

+1 −0
Original line number Diff line number Diff line
@@ -930,6 +930,7 @@ struct kvm_ppc_resize_hpt { 
#define KVM_CAP_PPC_SMT_POSSIBLE 147

#define KVM_CAP_HYPERV_SYNIC2 148

#define KVM_CAP_HYPERV_VP_INDEX 149

#define KVM_CAP_S390_AIS_MIGRATION 150



#ifdef KVM_CAP_IRQ_ROUTING

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