From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
Eduardo Habkost <ehabkost@redhat.com>,
Marc Zyngier <maz@kernel.org>, Andrew Jones <drjones@redhat.com>,
Huacai Chen <chenhuacai@kernel.org>,
Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
Anup Patel <anup.patel@wdc.com>,
Paul Mackerras <paulus@ozlabs.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Janosch Frank <frankja@linux.ibm.com>,
kvm-ppc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-mips@vger.kernel.org, kvm-riscv@lists.infradead.org,
linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 5/6] KVM: s390: Cap KVM_CAP_NR_VCPUS by num_online_cpus()
Date: Tue, 16 Nov 2021 17:34:42 +0100 [thread overview]
Message-ID: <20211116163443.88707-6-vkuznets@redhat.com> (raw)
In-Reply-To: <20211116163443.88707-1-vkuznets@redhat.com>
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 <borntraeger@de.ibm.com>
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;
--
2.33.1
next prev parent reply other threads:[~2021-11-16 16:36 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-16 16:34 [PATCH v2 0/6] KVM: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS and re-purpose it on x86 Vitaly Kuznetsov
2021-11-16 16:34 ` [PATCH v2 1/6] KVM: arm64: Cap KVM_CAP_NR_VCPUS by kvm_arm_default_max_vcpus() Vitaly Kuznetsov
2021-11-17 9:13 ` Marc Zyngier
2021-11-17 12:07 ` Paolo Bonzini
2021-11-16 16:34 ` [PATCH v2 2/6] KVM: MIPS: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS Vitaly Kuznetsov
2021-11-16 16:34 ` [PATCH v2 3/6] KVM: PPC: " Vitaly Kuznetsov
2021-11-16 16:34 ` [PATCH v2 4/6] KVM: RISC-V: " Vitaly Kuznetsov
2021-11-17 5:02 ` Anup Patel
2021-11-16 16:34 ` Vitaly Kuznetsov [this message]
2021-11-17 7:33 ` [PATCH v2 5/6] KVM: s390: Cap KVM_CAP_NR_VCPUS by num_online_cpus() Christian Borntraeger
2021-11-16 16:34 ` [PATCH v2 6/6] KVM: x86: Drop arbitraty KVM_SOFT_MAX_VCPUS Vitaly Kuznetsov
2021-11-17 12:12 ` Paolo Bonzini
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