From: "Luck, Tony" <tony.luck@intel.com>
To: "Pan, Jacob jun" <jacob.jun.pan@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
"Yu, Fenghua" <fenghua.yu@intel.com>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
H Peter Anvin <hpa@zytor.com>,
David Woodhouse <dwmw2@infradead.org>,
Lu Baolu <baolu.lu@linux.intel.com>,
"Hansen, Dave" <dave.hansen@intel.com>,
"Raj, Ashok" <ashok.raj@intel.com>,
"Jiang, Dave" <dave.jiang@intel.com>,
"Mehta, Sohil" <sohil.mehta@intel.com>,
"Shankar, Ravi V" <ravi.v.shankar@intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>
Subject: RE: [PATCH 5/7] x86/mmu: Allocate/free PASID
Date: Tue, 28 Apr 2020 20:59:43 +0000 [thread overview]
Message-ID: <3908561D78D1C84285E8C5FCA982C28F7F608EE2@ORSMSX115.amr.corp.intel.com> (raw)
In-Reply-To: <20200428134200.000010f7@intel.com>
>> So the driver needs to use flush/drain operations to make sure all
>> the in-flight work has completed before releasing/re-using the PASID.
>>
> Are you suggesting we should let driver also hold a reference of the
> PASID?
The sequence for bare metal is:
process is queuing requests to DSA
process exits (either deliberately, or crashes, or is killed)
kernel does exit processing
DSA driver is called as part of tear down of "mm"
issues drain/flush commands to ensure that all
queued operations on the PASID for this mm have
completed
PASID can be freed
There's a 1:1 map from "mm" to PASID ... so reference counting seems
like overkill. Once the kernel is in the "exit" path, we know that no more
work can be queued using this PASID.
-Tony
next prev parent reply other threads:[~2020-04-28 21:00 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-30 19:33 [PATCH 0/7] x86: tag application address space for devices Fenghua Yu
2020-03-30 19:33 ` [PATCH 1/7] docs: x86: Add a documentation for ENQCMD Fenghua Yu
2020-04-26 11:02 ` Thomas Gleixner
2020-04-27 20:13 ` Fenghua Yu
2020-03-30 19:33 ` [PATCH 2/7] x86/cpufeatures: Enumerate ENQCMD and ENQCMDS instructions Fenghua Yu
2020-04-26 11:06 ` Thomas Gleixner
2020-04-27 20:17 ` Fenghua Yu
2020-03-30 19:33 ` [PATCH 3/7] x86/fpu/xstate: Add supervisor PASID state for ENQCMD feature Fenghua Yu
2020-04-26 11:17 ` Thomas Gleixner
2020-04-27 20:33 ` Fenghua Yu
2020-03-30 19:33 ` [PATCH 4/7] x86/msr-index: Define IA32_PASID MSR Fenghua Yu
2020-04-26 11:22 ` Thomas Gleixner
2020-04-27 20:50 ` Fenghua Yu
2020-03-30 19:33 ` [PATCH 5/7] x86/mmu: Allocate/free PASID Fenghua Yu
2020-04-26 14:55 ` Thomas Gleixner
2020-04-27 22:18 ` Fenghua Yu
2020-04-27 23:44 ` Thomas Gleixner
2020-04-28 18:21 ` Jacob Pan (Jun)
2020-04-28 18:54 ` Thomas Gleixner
2020-04-28 19:07 ` Luck, Tony
2020-04-28 20:42 ` Jacob Pan (Jun)
2020-04-28 20:59 ` Luck, Tony [this message]
2020-04-28 22:13 ` Jacob Pan (Jun)
2020-04-28 22:32 ` Luck, Tony
2020-04-28 20:40 ` Jacob Pan (Jun)
2020-04-28 20:57 ` Fenghua Yu
2020-03-30 19:33 ` [PATCH 6/7] x86/traps: Fix up invalid PASID Fenghua Yu
2020-04-26 15:25 ` Thomas Gleixner
2020-04-27 20:11 ` Fenghua Yu
2020-04-28 0:13 ` Thomas Gleixner
2020-04-27 22:46 ` Raj, Ashok
2020-04-27 23:08 ` Luck, Tony
2020-04-28 0:20 ` Thomas Gleixner
2020-04-28 0:54 ` Thomas Gleixner
2020-04-28 1:08 ` Raj, Ashok
2020-03-30 19:33 ` [PATCH 7/7] x86/process: Clear PASID state for a newly forked/cloned thread Fenghua Yu
2020-04-22 20:41 ` [PATCH 0/7] x86: tag application address space for devices Fenghua Yu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3908561D78D1C84285E8C5FCA982C28F7F608EE2@ORSMSX115.amr.corp.intel.com \
--to=tony.luck@intel.com \
--cc=ashok.raj@intel.com \
--cc=baolu.lu@linux.intel.com \
--cc=bp@alien8.de \
--cc=dave.hansen@intel.com \
--cc=dave.jiang@intel.com \
--cc=dwmw2@infradead.org \
--cc=fenghua.yu@intel.com \
--cc=hpa@zytor.com \
--cc=iommu@lists.linux-foundation.org \
--cc=jacob.jun.pan@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=ravi.v.shankar@intel.com \
--cc=sohil.mehta@intel.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).