• Roman Kagan's avatar
    kvm: x86: hyperv: guest->host event signaling via eventfd · faeb7833
    Roman Kagan authored
    In Hyper-V, the fast guest->host notification mechanism is the
    SIGNAL_EVENT hypercall, with a single parameter of the connection ID to
    signal.
    
    Currently this hypercall incurs a user exit and requires the userspace
    to decode the parameters and trigger the notification of the potentially
    different I/O context.
    
    To avoid the costly user exit, process this hypercall and signal the
    corresponding eventfd in KVM, similar to ioeventfd.  The association
    between the connection id and the eventfd is established via the newly
    introduced KVM_HYPERV_EVENTFD ioctl, and maintained in an
    (srcu-protected) IDR.
    Signed-off-by: default avatarRoman Kagan <rkagan@virtuozzo.com>
    Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
    [asm/hyperv.h changes approved by KY Srinivasan. - Radim]
    Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
    faeb7833
x86.c 235 KB