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    xen/pv-on-hvm kexec: shutdown watches from old kernel · 254d1a3f
    Olaf Hering 提交于
    Add xs_reset_watches function to shutdown watches from old kernel after
    kexec boot.  The old kernel does not unregister all watches in the
    shutdown path.  They are still active, the double registration can not
    be detected by the new kernel.  When the watches fire, unexpected events
    will arrive and the xenwatch thread will crash (jumps to NULL).  An
    orderly reboot of a hvm guest will destroy the entire guest with all its
    resources (including the watches) before it is rebuilt from scratch, so
    the missing unregister is not an issue in that case.
    
    With this change the xenstored is instructed to wipe all active watches
    for the guest.  However, a patch for xenstored is required so that it
    accepts the XS_RESET_WATCHES request from a client (see changeset
    23839:42a45baf037d in xen-unstable.hg). Without the patch for xenstored
    the registration of watches will fail and some features of a PVonHVM
    guest are not available. The guest is still able to boot, but repeated
    kexec boots will fail.
    Signed-off-by: NOlaf Hering <olaf@aepfle.de>
    Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    254d1a3f
xs_wire.h 2.2 KB