diff options
| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2021-11-16 17:34:38 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-11-18 02:12:14 -0500 |
| commit | f60a00d7295057cb4baea5a321501efc72794453 (patch) | |
| tree | 4bd5794b032d48125f98268464160232ea2a3e56 /arch | |
| parent | b5aead0064f33ae5e693a364e3204fe1c0ac9af2 (diff) | |
KVM: arm64: Cap KVM_CAP_NR_VCPUS by kvm_arm_default_max_vcpus()
Generally, it doesn't make sense to return the recommended maximum number
of vCPUs which exceeds the maximum possible number of vCPUs.
Note: ARM64 is special as the value returned by KVM_CAP_MAX_VCPUS differs
depending on whether it is a system-wide ioctl or a per-VM one. Previously,
KVM_CAP_NR_VCPUS didn't have this difference and it seems preferable to
keep the status quo. Cap KVM_CAP_NR_VCPUS by kvm_arm_default_max_vcpus()
which is what gets returned by system-wide KVM_CAP_MAX_VCPUS.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20211116163443.88707-2-vkuznets@redhat.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/kvm/arm.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 2f03cbfefe67..e4727dc771bf 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -223,7 +223,14 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = 1; break; case KVM_CAP_NR_VCPUS: - r = num_online_cpus(); + /* + * ARM64 treats KVM_CAP_NR_CPUS differently from all other + * architectures, as it does not always bound it to + * KVM_CAP_MAX_VCPUS. It should not matter much because + * this is just an advisory value. + */ + r = min_t(unsigned int, num_online_cpus(), + kvm_arm_default_max_vcpus()); break; case KVM_CAP_MAX_VCPUS: case KVM_CAP_MAX_VCPU_ID: |