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    Subject[PATCH 4.14 117/222] tpm: Restore functionality to xen vtpm driver.
    Date
    4.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Dr. Greg Wettstein <greg@wind.enjellic.com>

    commit e487a0f52301293152a6f8c4e217f2a11dd808e3 upstream.

    Functionality of the xen-tpmfront driver was lost secondary to
    the introduction of xenbus multi-page support in commit ccc9d90a9a8b
    ("xenbus_client: Extend interface to support multi-page ring").

    In this commit pointer to location of where the shared page address
    is stored was being passed to the xenbus_grant_ring() function rather
    then the address of the shared page itself. This resulted in a situation
    where the driver would attach to the vtpm-stubdom but any attempt
    to send a command to the stub domain would timeout.

    A diagnostic finding for this regression is the following error
    message being generated when the xen-tpmfront driver probes for a
    device:

    <3>vtpm vtpm-0: tpm_transmit: tpm_send: error -62

    <3>vtpm vtpm-0: A TPM error (-62) occurred attempting to determine
    the timeouts

    This fix is relevant to all kernels from 4.1 forward which is the
    release in which multi-page xenbus support was introduced.

    Daniel De Graaf formulated the fix by code inspection after the
    regression point was located.

    Fixes: ccc9d90a9a8b ("xenbus_client: Extend interface to support multi-page ring")
    Signed-off-by: Dr. Greg Wettstein <greg@enjellic.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    [boris: Updated commit message, added Fixes tag]
    Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
    Cc: stable@vger.kernel.org # v4.1+
    Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
    Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

    ---
    drivers/char/tpm/xen-tpmfront.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/drivers/char/tpm/xen-tpmfront.c
    +++ b/drivers/char/tpm/xen-tpmfront.c
    @@ -203,7 +203,7 @@ static int setup_ring(struct xenbus_devi
    return -ENOMEM;
    }

    - rv = xenbus_grant_ring(dev, &priv->shr, 1, &gref);
    + rv = xenbus_grant_ring(dev, priv->shr, 1, &gref);
    if (rv < 0)
    return rv;


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