diff options
| author | Thomas Huth <thuth@redhat.com> | 2019-05-23 18:43:08 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-06-09 09:18:16 +0200 |
| commit | 527919d0cc5188c98b89f8357f7f7b36085c1a2c (patch) | |
| tree | d2bdda372e57198107ad476272cacd2a78d6da32 /arch/s390 | |
| parent | 163f75676ac2d4ddafd75e64fa22d7aae4291ad9 (diff) | |
KVM: s390: Do not report unusabled IDs via KVM_CAP_MAX_VCPU_ID
commit a86cb413f4bf273a9d341a3ab2c2ca44e12eb317 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 4f6adbea592b..d6fe229ac20e 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -428,6 +428,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) break; case KVM_CAP_NR_VCPUS: case KVM_CAP_MAX_VCPUS: + case KVM_CAP_MAX_VCPU_ID: r = KVM_S390_BSCA_CPU_SLOTS; if (!kvm_s390_use_sca_entries()) r = KVM_MAX_VCPUS; |