From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Thu, 9 Nov 2017 10:00:45 +0100
Subject: KVM: s390: provide a capability for AIS state migration
Patch-mainline: v4.15-rc1
Git-commit: da9a1446d248f673a8560ce46251ff620214ab7b
References: bsc#1077761
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: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Acked-by: Alexander Graf <agraf@suse.de>
---
Documentation/virtual/kvm/api.txt | 9 +++++++++
Documentation/virtual/kvm/devices/s390_flic.txt | 2 ++
arch/s390/kvm/kvm-s390.c | 1 +
include/uapi/linux/kvm.h | 1 +
4 files changed, 13 insertions(+)
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -4348,3 +4348,12 @@
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.
--- a/Documentation/virtual/kvm/devices/s390_flic.txt
+++ b/Documentation/virtual/kvm/devices/s390_flic.txt
@@ -151,6 +151,8 @@
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
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -395,6 +395,7 @@
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:
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -930,6 +930,7 @@
#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