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Diffstat (limited to 'Documentation/virt')
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 94d73ec52aba..421479a67da5 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -7494,6 +7494,27 @@ The valid bits in cap.args[0] are: generate a #UD within the guest. =================================== ============================================ +7.32 KVM_CAP_MAX_VCPU_ID +------------------------ + +:Architectures: x86 +:Target: VM +:Parameters: args[0] - maximum APIC ID value set for current VM +:Returns: 0 on success, -EINVAL if args[0] is beyond KVM_MAX_VCPU_IDS + supported in KVM or if it has been set. + +This capability allows userspace to specify maximum possible APIC ID +assigned for current VM session prior to the creation of vCPUs, saving +memory for data structures indexed by the APIC ID. Userspace is able +to calculate the limit to APIC ID values from designated +CPU topology. + +The value can be changed only until KVM_ENABLE_CAP is set to a nonzero +value or until a vCPU is created. Upon creation of the first vCPU, +if the value was set to zero or KVM_ENABLE_CAP was not invoked, KVM +uses the return value of KVM_CHECK_EXTENSION(KVM_CAP_MAX_VCPU_ID) as +the maximum APIC ID. + 8. Other capabilities. ====================== |