From: Ben Widawsky <ben.widawsky@intel.com>
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org,
Ira Weiny <ira.weiny@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
"Kelley, Sean V" <sean.v.kelley@intel.com>,
Rafael Wysocki <rafael.j.wysocki@intel.com>,
Bjorn Helgaas <helgaas@kernel.org>,
Jon Masters <jcm@jonmasters.org>,
Chris Browy <cbrowy@avery-design.com>,
Randy Dunlap <rdunlap@infradead.org>,
Christoph Hellwig <hch@infradead.org>,
daniel.lll@alibaba-inc.com
Subject: Re: [RFC PATCH v3 14/16] cxl/mem: Use CEL for enabling commands
Date: Thu, 14 Jan 2021 11:04:25 -0800 [thread overview]
Message-ID: <20210114190425.rxupmrjm3jfjorj4@intel.com> (raw)
In-Reply-To: <20210114183217.0000154c@Huawei.com>
On 21-01-14 18:32:17, Jonathan Cameron wrote:
> On Thu, 14 Jan 2021 10:13:40 -0800
> Ben Widawsky <ben.widawsky@intel.com> wrote:
>
> > On 21-01-14 18:02:11, Jonathan Cameron wrote:
> > > On Mon, 11 Jan 2021 14:51:19 -0800
> > > Ben Widawsky <ben.widawsky@intel.com> wrote:
> > >
> > > > The Command Effects Log (CEL) is specified in the CXL 2.0 specification.
> > > > The CEL is one of two types of logs, the other being vendor specific.
> > > > They are distinguished in hardware/spec via UUID. The CEL is immediately
> > > > useful for 2 things:
> > > > 1. Determine which optional commands are supported by the CXL device.
> > > > 2. Enumerate any vendor specific commands
> > > >
> > > > The CEL can be used by the driver to determine which commands are
> > > > available in the hardware (though it isn't, yet). That set of commands
> > > > might itself be a subset of commands which are available to be used via
> > > > CXL_MEM_SEND_COMMAND IOCTL.
> > > >
> > > > Prior to this, all commands that the driver exposed were explicitly
> > > > enabled. After this, only those commands that are found in the CEL are
> > > > enabled.
> > > >
> > > > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
> > >
> > > This patch made me wonder if the model for the command in quite right.
> > > I think it would end up simpler with a pair of payload pointers for send
> > > and receive (that can be equal when it makes sense).
> > >
> > > A few other things inline.
> > >
> > > Jonathan
> >
> > I'll address the others separately, but could you elaborate on this? I'm not
> > sure I follow your meaning.
>
> Further down in the review..
> "
> The fact that you end up bypassing the payload transfer stuff in mbox_cmd
> rather suggests it's not a particularly good model. + it keeps confusing
> me.
>
> While the hardware uses a single region for the payload, there is nothing
> saying the code has to work that way. Why not have separate payload_in and
> payload_out pointers? Occasionally you might set them to the same buffer, but
> elsewhere you could avoid the direct memcpy()s you are doing around the
> send_cmd().
>
> "
>
> Jonathan
>
>
Ah I was confused if that was a separate statement.
Can you specify the function prototype you're hoping for (or modification to the
structure)?
I really like the lowest level function to simply model the hardware. I get to
write the 8 steps out and clearly implement them.
I personally don't think it's so awkward, but again, give me something more
specific and I'll consider it.
next prev parent reply other threads:[~2021-01-14 19:05 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-11 22:51 [RFC PATCH v3 00/16] CXL 2.0 Support Ben Widawsky
2021-01-11 22:51 ` [RFC PATCH v3 01/16] docs: cxl: Add basic documentation Ben Widawsky
2021-01-11 22:51 ` [RFC PATCH v3 02/16] cxl/acpi: Add an acpi_cxl module for the CXL interconnect Ben Widawsky
2021-01-12 7:08 ` Randy Dunlap
2021-01-12 18:43 ` Jonathan Cameron
2021-01-12 19:43 ` Dan Williams
2021-01-12 22:06 ` Jonathan Cameron
2021-01-13 17:55 ` Kaneda, Erik
2021-01-20 19:27 ` Dan Williams
2021-01-20 19:18 ` Verma, Vishal L
2021-01-13 12:40 ` Rafael J. Wysocki
2021-01-20 19:21 ` Verma, Vishal L
2021-01-11 22:51 ` [RFC PATCH v3 03/16] cxl/acpi: add OSC support Ben Widawsky
2021-01-12 15:09 ` Rafael J. Wysocki
2021-01-12 18:48 ` Jonathan Cameron
2021-01-11 22:51 ` [RFC PATCH v3 04/16] cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints Ben Widawsky
2021-01-12 7:08 ` Randy Dunlap
2021-01-12 19:01 ` Jonathan Cameron
2021-01-12 20:06 ` Dan Williams
2021-01-11 22:51 ` [RFC PATCH v3 05/16] cxl/mem: Map memory device registers Ben Widawsky
2021-01-12 19:13 ` Jonathan Cameron
2021-01-12 19:21 ` Ben Widawsky
2021-01-12 20:40 ` Dan Williams
2021-01-11 22:51 ` [RFC PATCH v3 06/16] cxl/mem: Find device capabilities Ben Widawsky
2021-01-12 19:17 ` Jonathan Cameron
2021-01-12 19:22 ` Ben Widawsky
2021-01-11 22:51 ` [RFC PATCH v3 07/16] cxl/mem: Implement polled mode mailbox Ben Widawsky
2021-01-13 18:26 ` Jonathan Cameron
2021-01-14 17:40 ` Jonathan Cameron
2021-01-14 17:50 ` Ben Widawsky
2021-01-14 18:13 ` Jonathan Cameron
2021-01-11 22:51 ` [RFC PATCH v3 08/16] cxl/mem: Register CXL memX devices Ben Widawsky
2021-01-14 16:28 ` Jonathan Cameron
2021-01-11 22:51 ` [RFC PATCH v3 09/16] cxl/mem: Add basic IOCTL interface Ben Widawsky
2021-01-14 16:19 ` Jonathan Cameron
2021-01-11 22:51 ` [RFC PATCH v3 10/16] cxl/mem: Add send command Ben Widawsky
2021-01-14 17:10 ` Jonathan Cameron
2021-01-21 18:15 ` Ben Widawsky
2021-01-22 11:43 ` Jonathan Cameron
2021-01-22 17:08 ` Ben Widawsky
2021-01-11 22:51 ` [RFC PATCH v3 11/16] taint: add taint for direct hardware access Ben Widawsky
2021-01-11 22:51 ` [RFC PATCH v3 11/16] taint: add taint for unfettered " Ben Widawsky
2021-01-12 3:31 ` Ben Widawsky
2021-01-11 22:51 ` [RFC PATCH v3 12/16] cxl/mem: Add a "RAW" send command Ben Widawsky
2021-01-11 22:51 ` [RFC PATCH v3 13/16] cxl/mem: Create concept of enabled commands Ben Widawsky
2021-01-14 17:25 ` Jonathan Cameron
2021-01-21 18:40 ` Ben Widawsky
2021-01-22 11:28 ` Jonathan Cameron
2021-01-11 22:51 ` [RFC PATCH v3 14/16] cxl/mem: Use CEL for enabling commands Ben Widawsky
2021-01-14 18:02 ` Jonathan Cameron
2021-01-14 18:13 ` Ben Widawsky
2021-01-14 18:32 ` Jonathan Cameron
2021-01-14 19:04 ` Ben Widawsky [this message]
2021-01-14 19:24 ` Jonathan Cameron
2021-01-11 22:51 ` [RFC PATCH v3 15/16] cxl/mem: Add limited Get Log command (0401h) Ben Widawsky
2021-01-14 18:08 ` Jonathan Cameron
2021-01-23 0:14 ` Ben Widawsky
2021-01-11 22:51 ` [RFC PATCH v3 16/16] MAINTAINERS: Add maintainers of the CXL driver Ben Widawsky
2021-01-12 1:12 ` Joe Perches
[not found] ` <0f2a6d62-09d8-416f-e972-3e9869c3e1a6@alibaba-inc.com>
2021-01-12 15:17 ` [RFC PATCH v3 00/16] CXL 2.0 Support Ben Widawsky
2021-01-12 16:19 ` Bjorn Helgaas
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