From: Christoph Hellwig <hch@lst.de>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: 冯锐 <rui_feng@realsil.com.cn>, "Christoph Hellwig" <hch@lst.de>,
"Arnd Bergmann" <arnd@arndb.de>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>
Subject: Re: [PATCH 3/3] mmc: rtsx: Add SD Express mode support for RTS5261
Date: Tue, 27 Oct 2020 20:37:25 +0100 [thread overview]
Message-ID: <20201027193725.GA5579@lst.de> (raw)
In-Reply-To: <CAPDyKFrDLJtDkkWsSENLDu2xLqptkjDk94YxYfkfW7UPBoG+bg@mail.gmail.com>
On Tue, Oct 27, 2020 at 01:54:46PM +0100, Ulf Hansson wrote:
> > For information security purpose, some companies or business users set their notebook SD as "read only".
> > Because a lot of "read only" requirements from those companies or business users, notebook vendor controls reader write protect pin to achieve it.
> > Notebook BIOS might have option to choose "read only" or not.
> > This is why we think write protect is more important than speed.
>
> I understand that it may be used, in some way or the other to provide
> a hint to the operating system to mount it in read-only mode.
>
> Although, if there were a real security feature involved, the internal
> FW of the SD card would also monitor the switch, to support read-only
> mode. As I understand it, that's not the common case.
Yes. "Security" that relies on the driver to fall back to a different
mode doesn't work.
>
> > If you prefer to consistent behavior, I can ignore the write protect switch for SD express.
>
> At this point, I prefer if you would ignore the write protect switch
> in the SD controller driver.
Same here.
> According to Christoph, it should be possible to support read-only
> mode via PCIe/NVMe. You may need to add some tweaks to support this in
> the PCIe controller driver, but I can't advise you how to exactly do
> this.
The NVMe driver already supports write protected namespaces.
I'll ask my contact in the JEDEC SD card working group if there was
any consideration of the read-only handling for classic SD vs NVMe.
next prev parent reply other threads:[~2020-10-27 19:37 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-25 1:57 [PATCH 3/3] mmc: rtsx: Add SD Express mode support for RTS5261 rui_feng
2020-10-20 6:52 ` 答复: " 冯锐
2020-10-20 8:14 ` Ulf Hansson
2020-10-21 13:59 ` Ulf Hansson
2020-10-22 6:04 ` 答复: " 冯锐
2020-10-23 8:02 ` Ulf Hansson
2020-10-23 9:14 ` Christoph Hellwig
2020-10-23 12:12 ` Ulf Hansson
2020-10-23 12:18 ` Christoph Hellwig
2020-11-12 16:42 ` Christoph Hellwig
2020-11-17 2:09 ` 冯锐
2020-10-26 8:22 ` 答复: " 冯锐
2020-10-27 12:54 ` Ulf Hansson
2020-10-27 19:37 ` Christoph Hellwig [this message]
2020-10-28 2:08 ` 答复: " 冯锐
2020-10-28 10:05 ` 冯锐
2020-10-28 10:18 ` Ulf Hansson
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