linux-kernel - Re: [Xen-devel] [PATCH] tpm: Restore functionality to xen vtpm driver.

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Message-ID: <1bc136a8-b92c-f9bb-df2d-925cd41e9db4@oracle.com>
Date:   Tue, 10 Jan 2017 10:39:13 -0500
From:   Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:     greg@...ellic.com, linux-kernel@...r.kernel.org
Cc:     xen-users@...ts.xen.org, dgdegra@...ho.nsa.gov,
        stable@...r.kernel.org, xen-devel@...ts.xen.org
Subject: Re: [Xen-devel] [PATCH] tpm: Restore functionality to xen vtpm
 driver.

On 12/22/2016 03:41 PM, Dr. Greg Wettstein wrote:
> Functionality of the xen-tpmfront driver was lost secondary to
> the introduction of xenbus multi-page support in the following
> commit:
>
> ccc9d90a9a8b5c4ad7e9708ec41f75ff9e98d61d
>
> 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.
>
> Signed-off-by: Dr. Greg Wettstein <greg@...ellic.com>

Greg,

Are you planning to re-submit this?

Thanks.
-boris


> ---
>  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 5aaa268..dd83a07 100644
> --- a/drivers/char/tpm/xen-tpmfront.c
> +++ b/drivers/char/tpm/xen-tpmfront.c
> @@ -203,7 +203,7 @@ 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;
>