• Jan Kiszka's avatar
    KVM: x86: Rework INIT and SIPI handling · 66450a21
    Jan Kiszka authored
    
    
    A VCPU sending INIT or SIPI to some other VCPU races for setting the
    remote VCPU's mp_state. When we were unlucky, KVM_MP_STATE_INIT_RECEIVED
    was overwritten by kvm_emulate_halt and, thus, got lost.
    
    This introduces APIC events for those two signals, keeping them in
    kvm_apic until kvm_apic_accept_events is run over the target vcpu
    context. kvm_apic_has_events reports to kvm_arch_vcpu_runnable if there
    are pending events, thus if vcpu blocking should end.
    
    The patch comes with the side effect of effectively obsoleting
    KVM_MP_STATE_SIPI_RECEIVED. We still accept it from user space, but
    immediately translate it to KVM_MP_STATE_INIT_RECEIVED + KVM_APIC_SIPI.
    The vcpu itself will no longer enter the KVM_MP_STATE_SIPI_RECEIVED
    state. That also means we no longer exit to user space after receiving a
    SIPI event.
    
    Furthermore, we already reset the VCPU on INIT, only fixing up the code
    segment later on when SIPI arrives. Moreover, we fix INIT handling for
    the BSP: it never enter wait-for-SIPI but directly starts over on INIT.
    
    Tested-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
    Signed-off-by: Jan Kiszka's avatarJan Kiszka <jan.kiszka@siemens.com>
    Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
    66450a21