2018-09-13 19:47:49

by Boris Ostrovsky

[permalink] [raw]
Subject: [PATCH RESEND] tpm: Restore functionality to xen vtpm driver.

From: "Dr. Greg Wettstein" <[email protected]>

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.

Signed-off-by: Dr. Greg Wettstein <[email protected]>

[boris: fixed commit message formatting]
Signed-off-by: Boris Ostrovsky <[email protected]>
Cc: [email protected] # v4.1+
---
We've lost this patch a couple of years ago, re-submitting.


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



2018-09-13 20:28:58

by Jason Gunthorpe

[permalink] [raw]
Subject: Re: [PATCH RESEND] tpm: Restore functionality to xen vtpm driver.

On Thu, Sep 13, 2018 at 03:47:49PM -0400, Boris Ostrovsky wrote:
> From: "Dr. Greg Wettstein" <[email protected]>
>
> 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").

This should be in a Fixes: line..

> 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 <[email protected]>
>
> [boris: fixed commit message formatting]
> Signed-off-by: Boris Ostrovsky <[email protected]>
> Cc: [email protected] # v4.1+
> We've lost this patch a couple of years ago, re-submitting.
>
>
> 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
> +++ 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;
>

2018-09-16 19:20:36

by Jarkko Sakkinen

[permalink] [raw]
Subject: Re: [PATCH RESEND] tpm: Restore functionality to xen vtpm driver.

On Thu, Sep 13, 2018 at 03:47:49PM -0400, Boris Ostrovsky wrote:
> From: "Dr. Greg Wettstein" <[email protected]>
>
> 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.
>
> Signed-off-by: Dr. Greg Wettstein <[email protected]>
>
> [boris: fixed commit message formatting]
> Signed-off-by: Boris Ostrovsky <[email protected]>
> Cc: [email protected] # v4.1+
> ---
> We've lost this patch a couple of years ago, re-submitting.
>
>
> 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
>

Please add the fixes-line. Thanks.

/Jarkko