diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 28 |
1 files changed, 26 insertions, 2 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 49f043246f95..095095ae01dd 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -7908,8 +7908,10 @@ Will return -EBUSY if a VCPU has already been created. Valid feature flags in args[0] are:: - #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) - #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) + #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) + #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) + #define KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST (1ULL << 2) + #define KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST (1ULL << 3) Enabling KVM_X2APIC_API_USE_32BIT_IDS changes the behavior of KVM_SET_GSI_ROUTING, KVM_SIGNAL_MSI, KVM_SET_LAPIC, and KVM_GET_LAPIC, @@ -7922,6 +7924,28 @@ as a broadcast even in x2APIC mode in order to support physical x2APIC without interrupt remapping. This is undesirable in logical mode, where 0xff represents CPUs 0-7 in cluster 0. +Setting KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST instructs KVM to enable +Suppress EOI Broadcasts. KVM will advertise support for Suppress EOI +Broadcast to the guest and suppress LAPIC EOI broadcasts when the guest +sets the Suppress EOI Broadcast bit in the SPIV register. This flag is +supported only when using a split IRQCHIP. + +Setting KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST disables support for +Suppress EOI Broadcasts entirely, i.e. instructs KVM to NOT advertise +support to the guest. + +Modern VMMs should either enable KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST +or KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST. If not, legacy quirky +behavior will be used by KVM: in split IRQCHIP mode, KVM will advertise +support for Suppress EOI Broadcasts but not actually suppress EOI +broadcasts; for in-kernel IRQCHIP mode, KVM will not advertise support for +Suppress EOI Broadcasts. + +Setting both KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST and +KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST will fail with an EINVAL error, +as will setting KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST without a split +IRCHIP. + 7.8 KVM_CAP_S390_USER_INSTR0 ---------------------------- |