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* [PATCH v3] tpm: Restore functionality to xen vtpm driver.
@ 2018-09-17 22:53 Boris Ostrovsky
  2018-09-18 18:59 ` Jarkko Sakkinen
  0 siblings, 1 reply; 2+ messages in thread
From: Boris Ostrovsky @ 2018-09-17 22:53 UTC (permalink / raw)
  To: peterhuewe, jarkko.sakkinen, jgg
  Cc: linux-integrity, linux-kernel, xen-devel, jgross, dunlapg,
	Dr. Greg Wettstein, Dr . Greg Wettstein, Boris Ostrovsky, stable

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 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>

[boris: Updated commit message, 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;
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH v3] tpm: Restore functionality to xen vtpm driver.
  2018-09-17 22:53 [PATCH v3] tpm: Restore functionality to xen vtpm driver Boris Ostrovsky
@ 2018-09-18 18:59 ` Jarkko Sakkinen
  0 siblings, 0 replies; 2+ messages in thread
From: Jarkko Sakkinen @ 2018-09-18 18:59 UTC (permalink / raw)
  To: Boris Ostrovsky
  Cc: peterhuewe, jgg, linux-integrity, linux-kernel, xen-devel,
	jgross, dunlapg, Dr. Greg Wettstein, Dr . Greg Wettstein, stable

On Mon, Sep 17, 2018 at 06:53:33PM -0400, Boris Ostrovsky wrote:
> 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 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>
> 
> [boris: Updated commit message, 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;
>  
> -- 
> 2.17.1
> 

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

/Jarkko

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2018-09-17 22:53 [PATCH v3] tpm: Restore functionality to xen vtpm driver Boris Ostrovsky
2018-09-18 18:59 ` Jarkko Sakkinen

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