• Juergen Gross's avatar
    xen: add new hypercall buffer mapping device · c51b3c63
    Juergen Gross authored
    For passing arbitrary data from user land to the Xen hypervisor the
    Xen tools today are using mlock()ed buffers. Unfortunately the kernel
    might change access rights of such buffers for brief periods of time
    e.g. for page migration or compaction, leading to access faults in the
    hypervisor, as the hypervisor can't use the locks of the kernel.
    
    In order to solve this problem add a new device node to the Xen privcmd
    driver to easily allocate hypercall buffers via mmap(). The memory is
    allocated in the kernel and just mapped into user space. Marked as
    VM_IO the user mapping will not be subject to page migration et al.
    Signed-off-by: Juergen Gross's avatarJuergen Gross <jgross@suse.com>
    Reviewed-by: 's avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
    Signed-off-by: Juergen Gross's avatarJuergen Gross <jgross@suse.com>
    c51b3c63
privcmd.h 180 Bytes