• Juergen Gross's avatar
    xen: remove size limit of privcmd-buf mapping interface · 3941552a
    Juergen Gross authored
    Currently the size of hypercall buffers allocated via
    /dev/xen/hypercall is limited to a default of 64 memory pages. For live
    migration of guests this might be too small as the page dirty bitmask
    needs to be sized according to the size of the guest. This means
    migrating a 8GB sized guest is already exhausting the default buffer
    size for the dirty bitmap.
    
    There is no sensible way to set a sane limit, so just remove it
    completely. The device node's usage is limited to root anyway, so there
    is no additional DOS scenario added by allowing unlimited buffers.
    
    While at it make the error path for the -ENOMEM case a little bit
    cleaner by setting n_pages to the number of successfully allocated
    pages instead of the target size.
    
    Fixes: c51b3c63 ("xen: add new hypercall buffer mapping device")
    Cc: <stable@vger.kernel.org> #4.18
    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>
    3941552a
privcmd-buf.c 4.15 KB