From: michael.christie@oracle.com
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: target-devel@vger.kernel.org, linux-scsi@vger.kernel.org,
pbonzini@redhat.com, jasowang@redhat.com, mst@redhat.com,
sgarzare@redhat.com, virtualization@lists.linux-foundation.org
Subject: Re: vhost: multiple worker support
Date: Sat, 5 Jun 2021 17:40:17 -0500 [thread overview]
Message-ID: <faa6085b-dfd8-9ddf-8b52-20053ac182ef@oracle.com> (raw)
In-Reply-To: <523e6207-c380-9a9d-7a5d-7b7ee554d7f2@oracle.com>
On 6/3/21 5:16 PM, Mike Christie wrote:
> On 6/3/21 9:37 AM, Stefan Hajnoczi wrote:
>> On Tue, May 25, 2021 at 01:05:51PM -0500, Mike Christie wrote:
>>> The following patches apply over linus's tree or mst's vhost branch
>>> and my cleanup patchset:
>>>
>>> https://urldefense.com/v3/__https://lists.linuxfoundation.org/pipermail/virtualization/2021-May/054354.html__;!!GqivPVa7Brio!P55eslnMW_iZkoTUZckwhnSw_9Z35JBScgtSYRh4CMFTRkSsWwKOYqY0huUfBfIPM8BV$
>>>
>>> These patches allow us to support multiple vhost workers per device. I
>>> ended up just doing Stefan's original idea where userspace has the
>>> kernel create a worker and we pass back the pid. This has the benefit
>>> over the workqueue and userspace thread approach where we only have
>>> one'ish code path in the kernel during setup to detect old tools. The
>>> main IO paths and device/vq setup/teardown paths all use common code.
>>>
>>> The kernel patches here allow us to then do N workers device and also
>>> share workers across devices.
>>>
>>> I've also included a patch for qemu so you can get an idea of how it
>>> works. If we are ok with the kernel code then I'll break that up into
>>> a patchset and send to qemu-devel.
>>
>> It seems risky to allow userspace process A to "share" a vhost worker
>> thread with userspace process B based on a matching pid alone. Should
>> they have ptrace_may_access() or similar?
>>
>
> I'm not sure. I already made it a little restrictive in this posting, but
Made a mistake here. In this posting I did not make it restrictive and
I was allowing any old 2 processes to share. So we would need something
like ptrace_may_access if go this route.
If we restrict sharing workers with the same owner, then I'm not sure if
need anything.
next prev parent reply other threads:[~2021-06-05 22:40 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-25 18:05 vhost: multiple worker support Mike Christie
2021-05-25 18:05 ` [PATCH 1/9] vhost: move worker thread fields to new struct Mike Christie
2021-06-03 10:16 ` Stefan Hajnoczi
2021-05-25 18:05 ` [PATCH 2/9] vhost: move vhost worker creation to kick setup Mike Christie
2021-06-03 10:28 ` Stefan Hajnoczi
2021-05-25 18:05 ` [PATCH 3/9] vhost: modify internal functions to take a vhost_worker Mike Christie
2021-06-03 10:45 ` Stefan Hajnoczi
2021-05-25 18:05 ` [PATCH 4/9] vhost: allow vhost_polls to use different vhost_workers Mike Christie
2021-06-03 13:51 ` Stefan Hajnoczi
2021-05-25 18:05 ` [PATCH 5/9] vhost-scsi: flush IO vqs then send TMF rsp Mike Christie
2021-06-03 13:54 ` Stefan Hajnoczi
2021-05-25 18:05 ` [PATCH 6/9] vhost-scsi: make SCSI cmd completion per vq Mike Christie
2021-06-03 13:57 ` Stefan Hajnoczi
2021-05-25 18:05 ` [PATCH 7/9] vhost: allow userspace to create workers Mike Christie
2021-06-03 14:30 ` Stefan Hajnoczi
2021-06-05 23:53 ` michael.christie
2021-06-07 15:19 ` Stefan Hajnoczi
2021-06-09 21:03 ` Mike Christie
2021-06-10 8:06 ` Stefan Hajnoczi
2021-06-18 2:49 ` Mike Christie
2021-06-21 13:41 ` Stefan Hajnoczi
2021-05-25 18:05 ` [PATCH 8/9] vhost: add vhost_dev pointer to vhost_work Mike Christie
2021-06-03 14:31 ` Stefan Hajnoczi
2021-05-25 18:06 ` [PATCH 9/9] vhost: support sharing workers across devs Mike Christie
2021-06-03 14:32 ` Stefan Hajnoczi
2021-06-07 2:18 ` Jason Wang
2021-06-03 10:13 ` vhost: multiple worker support Stefan Hajnoczi
2021-06-03 18:45 ` Mike Christie
2021-06-03 14:37 ` Stefan Hajnoczi
2021-06-03 22:16 ` Mike Christie
2021-06-05 22:40 ` michael.christie [this message]
2021-06-07 15:23 ` Stefan Hajnoczi
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