Re: [PATCH v1 3/3] misc: ls6000se-sdf: Add driver for Loongson 6000SE SDF

[Xi Ruoyao <xry111@xry111.site>]

On Wed, 2025-01-15 at 10:39 +0000, Zheng, Yaofei wrote:
> 
> Internal Use - Confidential
> > On Wed, Jan 15, 2025 at 10:58:52AM +0800, Qunqin Zhao wrote:
> > > 
> > > 在 2025/1/14 下午9:21, Greg Kroah-Hartman 写道:
> > > > On Tue, Jan 14, 2025 at 06:43:24PM +0800, Xi Ruoyao wrote:
> > > > > On Tue, 2025-01-14 at 11:17 +0100, Arnd Bergmann wrote:
> > > > > > On Tue, Jan 14, 2025, at 10:55, Qunqin Zhao wrote:
> > > > > > > Loongson Secure Device Function device supports the functions
> > > > > > > specified in "GB/T 36322-2018". This driver is only
> > > > > > > responsible for sending user data to SDF devices or returning SDF device data to users.
> > > > > > I haven't been able to find a public version of the standard
> > > > > A public copy is available at
> > > > > https://openstd.samr.gov.cn/bzgk/gb/ne
> > > > > wGbInfo?hcno=69E793FE1769D120C82F78447802E14F__;!!LpKI!g7kUt84vOxl
> > > > > 65EbgAJzXoupsM5Bx3FjUDPnKHaEw5RUoyUouS6IwCerRSZ7MIWi0Bw5WHaM2YP7pZ
> > > > > IcYiDQOLf3F$ [openstd[.]samr[.]gov[.]cn], pressing the blue
> > > > > "online preview" button, enter a captcha and you can see it.  But the copy is in Chinese, and there's an explicit notice saying translating this copy is forbidden, so I cannot translate it for you either.
> > > > > 
> > > > > > but
> > > > > > from the table of contents it sounds like this is a standard for
> > > > > > cryptographic functions that would otherwise be implemented by a
> > > > > > driver in drivers/crypto/ so it can use the normal abstractions
> > > > > > for both userspace and in-kernel users.
> > > > > > 
> > > > > > Is there some reason this doesn't work?
> > > > > I'm not an lawyer but I guess contributing code for that may have
> > > > > some "cryptography code export rule compliance" issue.
> > > > Issue with what?  And why?  It's enabling the functionality of the
> > > > hardware either way, so the same rules should apply no matter where
> > > > the driver ends up in or what apis it is written against, right?
> > > 
> > > SDF and tpm2.0 are both  "library specifications",  which means that
> > > 
> > > it supports a wide variety of functions not only cryptographic
> > > functions,
> > > 
> > > but unlike tpm2.0, SDF is only used in China.
> > > 
> > > You can refer to the tpm2.0 specification:
> > > https://trustedcomputinggroup.org/resource
> > > /tpm-library-specification/__;!!LpKI!g7kUt84vOxl65EbgAJzXoupsM5Bx3FjUD
> > > PnKHaEw5RUoyUouS6IwCerRSZ7MIWi0Bw5WHaM2YP7pZIcYiCFoP-hu$
> > > [trustedcomputinggroup[.]org]
> > 
> > So this is an accelerator device somehow?  If it provides crypto functions, it must follow the crypto api, you can't just provide a "raw"
> > char device node for it as that's not going to be portable at all.
> > Please fit it into the proper kernel subsystem for the proper user/kernel api needed to drive this hardware.
> > 
> > thanks,
> > 
> > greg k-h
> > 
> 
> Hi Qunqin and Ruoyao,
> 
> "GB/T 36322-2018" is just a chinese national standard, not ISO standard, not an
> enforced one, "T" repensts "推荐" which means "recommend". From what I understand
>  it defined series of C API for cryptography devices after reading the standard.
> Linux kernel have user space socket interface using type AF_ALG, and out of tree
>  driver "Cryptodev". From my view: "GB/T 36322-2018" can be user space library
> using socket interface, just like openssl, if must do it char dev way, do it out
>  of tree, and reuse kernel space crypto API.

Figure 1 of the section 6.1 says the GB/T 36322 interface is between
"cryptography device" and "generic cryptography service and cryptography
device management."  IMO in a Linux (or any monolithic-kernel) system at
least "cryptography device management" is the job of the kernel, thus
exposing the GB/T 36322 interface directly to the userspace seems not a
good idea.

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University