From: Dan Williams <dan.j.williams@intel.com>
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Ira Weiny <ira.weiny@intel.com>,
linux-cxl@vger.kernel.org, Linux PCI <linux-pci@vger.kernel.org>,
Bjorn Helgaas <helgaas@kernel.org>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Ben Widawsky <ben.widawsky@intel.com>,
Chris Browy <cbrowy@avery-design.com>,
Linux ACPI <linux-acpi@vger.kernel.org>,
"Schofield, Alison" <alison.schofield@intel.com>,
Vishal L Verma <vishal.l.verma@intel.com>,
Linuxarm <linuxarm@huawei.com>, Fangjian <f.fangjian@huawei.com>,
Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [RFC PATCH v3 2/4] PCI/doe: Add Data Object Exchange support
Date: Wed, 19 May 2021 17:16:28 -0700 [thread overview]
Message-ID: <CAPcyv4hRcdw1N2b1WsVOLqDwZQSt6o=fQsn=VPtA5gpJFY-Qgw@mail.gmail.com> (raw)
In-Reply-To: <CAPcyv4hCCqEPzGKh4hyjHEBE3jDn9iTA_WUOZMFptHKrX-2J_A@mail.gmail.com>
On Wed, May 19, 2021 at 4:51 PM Dan Williams <dan.j.williams@intel.com> wrote:
[..]
> > The short answer is that lock requirement, in the above note, rules
> > out safe direct userspace use of the DOE (unless we can tell the kernel
> > is not going to ever use it).
>
> Linux has the mitigation for that situation defined already. It's the
> mechanism for /dev/mem and pci-mmap exclusion: disable the driver to
> enable unfettered userspace access (modulo kernel-lockdown is
> disabled).
>
Note that when I say "driver" here, it need not necessarily be the
cxl_pci driver for the memory expander. For example, DOE functionality
could be handled by an aux-bus device+driver where that can be
unloaded without taking down the rest of the CXL driver.
next prev parent reply other threads:[~2021-05-20 0:16 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-19 16:54 [RFC PATCH v3 0/4] PCI Data Object Exchange support + CXL CDAT Jonathan Cameron
2021-04-19 16:54 ` [RFC PATCH v3 1/4] PCI: Add vendor ID for the PCI SIG Jonathan Cameron
2021-04-19 16:54 ` [RFC PATCH v3 2/4] PCI/doe: Add Data Object Exchange support Jonathan Cameron
2021-05-06 21:59 ` Ira Weiny
2021-05-11 16:50 ` Jonathan Cameron
2021-05-13 21:20 ` Dan Williams
2021-05-14 8:47 ` Jonathan Cameron
2021-05-14 11:15 ` Lorenzo Pieralisi
2021-05-14 12:39 ` Jonathan Cameron
2021-05-14 18:37 ` Dan Williams
2021-05-17 8:40 ` Jonathan Cameron
2021-05-17 8:51 ` Greg KH
2021-05-17 17:21 ` Dan Williams
2021-05-18 10:04 ` Jonathan Cameron
2021-05-19 14:18 ` Dan Williams
2021-05-19 15:11 ` Jonathan Cameron
2021-05-19 15:29 ` Dan Williams
2021-05-19 16:20 ` Jonathan Cameron
2021-05-19 16:33 ` Jonathan Cameron
2021-05-19 16:53 ` Dan Williams
2021-05-19 17:00 ` Jonathan Cameron
2021-05-19 19:20 ` Dan Williams
2021-05-19 20:18 ` Jonathan Cameron
2021-05-19 23:51 ` Dan Williams
2021-05-20 0:16 ` Dan Williams [this message]
2021-05-20 8:22 ` Jonathan Cameron
2021-05-07 9:36 ` Jonathan Cameron
2021-05-07 23:10 ` Bjorn Helgaas
2021-05-12 12:44 ` Jonathan Cameron
2021-04-19 16:54 ` [RFC PATCH v3 3/4] cxl/mem: Add CDAT table reading from DOE Jonathan Cameron
2021-04-19 16:54 ` [RFC PATCH v3 4/4] cxl/mem: Add a debug parser for CDAT commands Jonathan Cameron
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