Messages in this thread | | | Date | Mon, 1 Feb 2021 13:24:00 -0500 | From | Konrad Rzeszutek Wilk <> | Subject | Re: [PATCH 09/14] cxl/mem: Add a "RAW" send command |
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On Fri, Jan 29, 2021 at 04:24:33PM -0800, Ben Widawsky wrote: > The CXL memory device send interface will have a number of supported > commands. The raw command is not such a command. Raw commands allow > userspace to send a specified opcode to the underlying hardware and > bypass all driver checks on the command. This is useful for a couple of > usecases, mainly: > 1. Undocumented vendor specific hardware commands > 2. Prototyping new hardware commands not yet supported by the driver
This sounds like a recipe for ..
In case you really really want this may I recommend you do two things:
- Wrap this whole thing with #ifdef CONFIG_CXL_DEBUG_THIS_WILL_DESTROY_YOUR_LIFE
(or something equivalant to make it clear this should never be enabled in production kernels).
- Add a nice big fat printk in dmesg telling the user that they are creating a unstable parallel universe that will lead to their blood pressure going sky-high, or perhaps something more professional sounding.
- Rethink this. Do you really really want to encourage vendors to use this raw API instead of them using the proper APIs?
> > While this all sounds very powerful it comes with a couple of caveats: > 1. Bug reports using raw commands will not get the same level of > attention as bug reports using supported commands (via taint). > 2. Supported commands will be rejected by the RAW command. > > With this comes new debugfs knob to allow full access to your toes with > your weapon of choice.
Problem is that debugfs is no longer "debug" but is enabled in production kernel.
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