• Andrey Smetanin's avatar
    kvm/x86: Hyper-V synthetic interrupt controller · 5c919412
    Andrey Smetanin authored
    SynIC (synthetic interrupt controller) is a lapic extension,
    which is controlled via MSRs and maintains for each vCPU
     - 16 synthetic interrupt "lines" (SINT's); each can be configured to
       trigger a specific interrupt vector optionally with auto-EOI
       semantics
     - a message page in the guest memory with 16 256-byte per-SINT message
       slots
     - an event flag page in the guest memory with 16 2048-bit per-SINT
       event flag areas
    
    The host triggers a SINT whenever it delivers a new message to the
    corresponding slot or flips an event flag bit in the corresponding area.
    The guest informs the host that it can try delivering a message by
    explicitly asserting EOI in lapic or writing to End-Of-Message (EOM)
    MSR.
    
    The userspace (qemu) triggers interrupts and receives EOM notifications
    via irqfd with resampler; for that, a GSI is allocated for each
    configured SINT, and irq_routing api is extended to support GSI-SINT
    mapping.
    
    Changes v4:
    * added activation of SynIC by vcpu KVM_ENABLE_CAP
    * added per SynIC active flag
    * added deactivation of APICv upon SynIC activation
    
    Changes v3:
    * added KVM_CAP_HYPERV_SYNIC and KVM_IRQ_ROUTING_HV_SINT notes into
    docs
    
    Changes v2:
    * do not use posted interrupts for Hyper-V SynIC AutoEOI vectors
    * add Hyper-V SynIC vectors into EOI exit bitmap
    * Hyper-V SyniIC SINT msr write logic simplified
    Signed-off-by: default avatarAndrey Smetanin <asmetanin@virtuozzo.com>
    Reviewed-by: default avatarRoman Kagan <rkagan@virtuozzo.com>
    Signed-off-by: default avatarDenis V. Lunev <den@openvz.org>
    CC: Gleb Natapov <gleb@kernel.org>
    CC: Paolo Bonzini <pbonzini@redhat.com>
    CC: Roman Kagan <rkagan@virtuozzo.com>
    CC: Denis V. Lunev <den@openvz.org>
    CC: qemu-devel@nongnu.org
    Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
    5c919412
api.txt 117 KB