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    SubjectRe: [PATCH v6 7/8] vhost: cross-endian support for legacy devices
    On Fri, 24 Apr 2015 14:27:24 +0200
    Greg Kurz <gkurz@linux.vnet.ibm.com> wrote:

    > This patch brings cross-endian support to vhost when used to implement
    > legacy virtio devices. Since it is a relatively rare situation, the
    > feature availability is controlled by a kernel config option (not set
    > by default).
    >
    > The vq->is_le boolean field is added to cache the endianness to be
    > used for ring accesses. It defaults to native endian, as expected
    > by legacy virtio devices. When the ring gets active, we force little
    > endian if the device is modern. When the ring is deactivated, we
    > revert to the native endian default.
    >
    > If cross-endian was compiled in, a vq->user_be boolean field is added
    > so that userspace may request a specific endianness. This field is
    > used to override the default when activating the ring of a legacy
    > device. It has no effect on modern devices.
    >
    > Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
    > ---
    >
    > Changes since v5:
    > - fixed description in Kconfig
    > - fixed error description in uapi header
    > - dropped useless semi-colon in the vhost_vq_reset_user_be() stub
    >
    > drivers/vhost/Kconfig | 15 ++++++++
    > drivers/vhost/vhost.c | 85 +++++++++++++++++++++++++++++++++++++++++++-
    > drivers/vhost/vhost.h | 11 +++++-
    > include/uapi/linux/vhost.h | 14 +++++++
    > 4 files changed, 122 insertions(+), 3 deletions(-)
    >
    Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>



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