Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 17 Feb 2021 14:16:59 +0000
From:   Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To:     Ben Widawsky <ben.widawsky@intel.com>
CC:     <linux-cxl@vger.kernel.org>, <linux-acpi@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-nvdimm@lists.01.org>,
        <linux-pci@vger.kernel.org>, Bjorn Helgaas <helgaas@kernel.org>,
        "Chris Browy" <cbrowy@avery-design.com>,
        Christoph Hellwig <hch@infradead.org>,
        "Dan Williams" <dan.j.williams@intel.com>,
        David Hildenbrand <david@redhat.com>,
        David Rientjes <rientjes@google.com>,
        Ira Weiny <ira.weiny@intel.com>,
        "Jon Masters" <jcm@jonmasters.org>,
        Rafael Wysocki <rafael.j.wysocki@intel.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Vishal Verma <vishal.l.verma@intel.com>,
        "John Groves (jgroves)" <jgroves@micron.com>,
        "Kelley, Sean V" <sean.v.kelley@intel.com>,
        kernel test robot <lkp@intel.com>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH v5 4/9] cxl/mem: Add basic IOCTL interface
Message-ID: <20210217141659.000064ec@Huawei.com>
In-Reply-To: <20210217040958.1354670-5-ben.widawsky@intel.com>
References: <20210217040958.1354670-1-ben.widawsky@intel.com>
        <20210217040958.1354670-5-ben.widawsky@intel.com>
Organization: Huawei Technologies Research and Development (UK) Ltd.
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
Precedence: bulk

On Tue, 16 Feb 2021 20:09:53 -0800
Ben Widawsky <ben.widawsky@intel.com> wrote:

> Add a straightforward IOCTL that provides a mechanism for userspace to
> query the supported memory device commands. CXL commands as they appear
> to userspace are described as part of the UAPI kerneldoc. The command
> list returned via this IOCTL will contain the full set of commands that
> the driver supports, however, some of those commands may not be
> available for use by userspace.
> 
> Memory device commands first appear in the CXL 2.0 specification. They
> are submitted through a mailbox mechanism specified in the CXL 2.0
> specification.
> 
> The send command allows userspace to issue mailbox commands directly to
> the hardware. The list of available commands to send are the output of
> the query command. The driver verifies basic properties of the command
> and possibly inspect the input (or output) payload to determine whether
> or not the command is allowed (or might taint the kernel).
> 
> Reported-by: kernel test robot <lkp@intel.com> # bug in earlier revision
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
> Reviewed-by: Dan Williams <dan.j.williams@intel.com> (v2)

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>