From: "Dr. Greg Wettstein" greg@wind.enjellic.com
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 a pointer to the shared page address 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
[boris: fixed commit message formatting, added Fixes tag] Signed-off-by: Boris Ostrovsky boris.ostrovsky@oracle.com Cc: stable@vger.kernel.org # v4.1+ --- drivers/char/tpm/xen-tpmfront.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/char/tpm/xen-tpmfront.c b/drivers/char/tpm/xen-tpmfront.c index 911475d36800..b150f87f38f5 100644 --- a/drivers/char/tpm/xen-tpmfront.c +++ b/drivers/char/tpm/xen-tpmfront.c @@ -264,7 +264,7 @@ static int setup_ring(struct xenbus_device *dev, struct tpm_private *priv) 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;