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authorThomas Huth <thuth@redhat.com>2019-05-23 18:43:08 +0200
committerChristian Borntraeger <borntraeger@de.ibm.com>2019-05-28 15:52:19 +0200
commita86cb413f4bf273a9d341a3ab2c2ca44e12eb317 (patch)
tree9cadf1c3a9f0dd172677d5c30884edca37c3851a /arch/mips
parenteb1f2f387db8c0d084581fb26e7faffde700bc8e (diff)
downloadlinux-a86cb413f4bf273a9d341a3ab2c2ca44e12eb317.tar.bz2
KVM: s390: Do not report unusabled IDs via KVM_CAP_MAX_VCPU_ID
KVM_CAP_MAX_VCPU_ID is currently always reporting KVM_MAX_VCPU_ID on all architectures. However, on s390x, the amount of usable CPUs is determined during runtime - it is depending on the features of the machine the code is running on. Since we are using the vcpu_id as an index into the SCA structures that are defined by the hardware (see e.g. the sca_add_vcpu() function), it is not only the amount of CPUs that is limited by the hard- ware, but also the range of IDs that we can use. Thus KVM_CAP_MAX_VCPU_ID must be determined during runtime on s390x, too. So the handling of KVM_CAP_MAX_VCPU_ID has to be moved from the common code into the architecture specific code, and on s390x we have to return the same value here as for KVM_CAP_MAX_VCPUS. This problem has been discovered with the kvm_create_max_vcpus selftest. With this change applied, the selftest now passes on s390x, too. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Thomas Huth <thuth@redhat.com> Message-Id: <20190523164309.13345-9-thuth@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/mips')
-rw-r--r--arch/mips/kvm/mips.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 6d0517ac18e5..0369f26ab96d 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -1122,6 +1122,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_MAX_VCPUS:
r = KVM_MAX_VCPUS;
break;
+ case KVM_CAP_MAX_VCPU_ID:
+ r = KVM_MAX_VCPU_ID;
+ break;
case KVM_CAP_MIPS_FPU:
/* We don't handle systems with inconsistent cpu_has_fpu */
r = !!raw_cpu_has_fpu;