From: "Allen Hubbe" <Allen.Hubbe@dell.com>
To: "'Logan Gunthorpe'" <logang@deltatee.com>,
<linux-ntb@googlegroups.com>, <linux-kernel@vger.kernel.org>
Cc: "'Jon Mason'" <jdmason@kudzu.us>
Subject: RE: [PATCH 2/2] ntb_hw_switchtec: Check for alignment of the buffer in mw_set_trans()
Date: Mon, 11 Dec 2017 14:17:38 -0500 [thread overview]
Message-ID: <000301d372b4$b6042100$220c6300$@dell.com> (raw)
In-Reply-To: <d06cf74e-125c-6281-9361-22bac3468251@deltatee.com>
From: Logan Gunthorpe
> mw_get_align doesn't communicate the fact that the buffer has to be
> aligned by its size.
Is that not the purpose of the addr_align out parameter of ntb_mw_get_align()?
> It may also be that all hardware does not have this
> restriction (ie. if the hardware adds to the base address instead of
> just replacing the lower bits).
>
> There is definitely a need to print this error somewhere as I hit this
> case and it caused very weird behavior. It was a huge pain to debug.
> Also, it's a security issue and huge bug if we end up mapping the memory
> we didn't think we were mapping.
Of course the driver should validate its parameters not allow bad mappings. I was only commenting on the dev_err() message to the console.
What makes best sense for client drivers with regards to ntb api changes is a fair argument. Let's see what others say.
> I don't think it's a good idea for us
> to require clients to check this as that requires a number of checks and
> a client author may forget to add it to their driver. I'd maybe go with
> a check in ntb_mw_set_trans before calling the driver, but that only
> makes sense if all hardware has the same requirement.
>
> Logan
next prev parent reply other threads:[~2017-12-11 19:18 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-09 0:02 [PATCH 1/2] ntb_transport: Fix bug with max_mw_size parameter Logan Gunthorpe
2017-12-09 0:02 ` [PATCH 2/2] ntb_hw_switchtec: Check for alignment of the buffer in mw_set_trans() Logan Gunthorpe
2017-12-11 14:58 ` Allen Hubbe
2017-12-11 17:14 ` Logan Gunthorpe
2017-12-11 19:17 ` Allen Hubbe [this message]
2017-12-11 19:28 ` Logan Gunthorpe
2017-12-11 20:06 ` Allen Hubbe
2017-12-11 20:38 ` Logan Gunthorpe
2017-12-11 14:55 ` [PATCH 1/2] ntb_transport: Fix bug with max_mw_size parameter Allen Hubbe
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