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Diffstat (limited to 'Documentation/virt/kvm/x86/errata.rst')
| -rw-r--r-- | Documentation/virt/kvm/x86/errata.rst | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/x86/errata.rst b/Documentation/virt/kvm/x86/errata.rst index 410e0aa63493..49a05f24747b 100644 --- a/Documentation/virt/kvm/x86/errata.rst +++ b/Documentation/virt/kvm/x86/errata.rst @@ -37,3 +37,14 @@ Nested virtualization features ------------------------------ TBD + +x2APIC +------ +When KVM_X2APIC_API_USE_32BIT_IDS is enabled, KVM activates a hack/quirk that +allows sending events to a single vCPU using its x2APIC ID even if the target +vCPU has legacy xAPIC enabled, e.g. to bring up hotplugged vCPUs via INIT-SIPI +on VMs with > 255 vCPUs. A side effect of the quirk is that, if multiple vCPUs +have the same physical APIC ID, KVM will deliver events targeting that APIC ID +only to the vCPU with the lowest vCPU ID. If KVM_X2APIC_API_USE_32BIT_IDS is +not enabled, KVM follows x86 architecture when processing interrupts (all vCPUs +matching the target APIC ID receive the interrupt). |