Re: [PATCH v2 5/6] KVM: s390: Cap KVM_CAP_NR_VCPUS by num_online_cpus()
From: Christian Borntraeger <borntraeger@linux.ibm.com>
Date: 2021-11-17 07:34:06
Also in:
kvm, kvm-riscv, linux-mips, linux-s390, lkml
Am 16.11.21 um 17:34 schrieb Vitaly Kuznetsov:
KVM_CAP_NR_VCPUS is a legacy advisory value which on other architectures return num_online_cpus() caped by KVM_CAP_NR_VCPUS or something else (ppc and arm64 are special cases). On s390, KVM_CAP_NR_VCPUS returns the same as KVM_CAP_MAX_VCPUS and this may turn out to be a bad 'advice'. Switch s390 to returning caped num_online_cpus() too. Acked-by: Christian Borntraeger <redacted>
you can also add Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com> (yes I am changing my default address, but the other should continue to work)
quoted hunk ↗ jump to hunk
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> --- arch/s390/kvm/kvm-s390.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 6a6dd5e1daf6..1cfe36f6432e 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c@@ -585,6 +585,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = KVM_MAX_VCPUS; else if (sclp.has_esca && sclp.has_64bscao) r = KVM_S390_ESCA_CPU_SLOTS; + if (ext == KVM_CAP_NR_VCPUS) + r = min_t(unsigned int, num_online_cpus(), r); break; case KVM_CAP_S390_COW: r = MACHINE_HAS_ESOP;
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