MFC 309240,309242,309244,309245,309319,309670

MFC 309240,309242,309244,309245,309319,309670

309240
    hyperv/vmbus: Add result polling support for xact API.

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D8633

309242
    hyperv/vmbus: Add result polling support for message Hypercall API.

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D8634

309244
    hyperv/vmbus: Add exec cancel support for message Hypercall API.

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D8635

309245
    hyperv/vmbus: Use poll/cancel APIs to wait for the CHOPEN response.

    Since hypervisor does not respond CHOPEN to a revoked channel.

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D8636

309319
    hypver/vmbus: Remove extra assertion.

    It is asserted by vmbus_chan_gpadl_connect() now.

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D8660

309670
    hyperv/vmbus: Use pause if possible.

    This makes booting on Hyper-V w/ small # of vCPUs work properly.

    Reported by:    Hongxiong Xian <v-hoxian microsoft com>, Hongjiang Zhang <honzhan microsoft com>
    Sponsored by:   Microsoft

git-svn-id: svn://svn.freebsd.org/base/stable/10@310761 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f