tpm: Restore functionality to xen vtpm driver.

Dr. Greg Wettstein · Jarkko Sakkinen · commit e487a0f52301 · 2018-10-05T13:47:34.000+03:00
Functionality of the xen-tpmfront driver was lost secondary to the introduction of xenbus multi-page support in commit ccc9d90 ("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: ccc9d90 ("xenbus_client: Extend interface to support multi-page ring") Signed-off-by: Dr. Greg Wettstein <greg@enjellic.com> [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>
diff --git 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;
 

Original file line number	Diff line number	Diff line change
`@@ -264,7 +264,7 @@ static int setup_ring(struct xenbus_device dev, struct tpm_private priv)`
`264`	`264`	`return -ENOMEM;`
`265`	`265`	`}`
`266`	`266`
`267`		`- rv = xenbus_grant_ring(dev, &priv->shr, 1, &gref);`
	`267`	`+ rv = xenbus_grant_ring(dev, priv->shr, 1, &gref);`
`268`	`268`	`if (rv < 0)`
`269`	`269`	`return rv;`
`270`	`270`