From: Jason Gunthorpe <jgg@nvidia.com>
To: "Zeng, Xin" <xin.zeng@intel.com>
Cc: Yishai Hadas <yishaih@nvidia.com>,
"herbert@gondor.apana.org.au" <herbert@gondor.apana.org.au>,
"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
"shameerali.kolothum.thodi@huawei.com"
<shameerali.kolothum.thodi@huawei.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
"linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
qat-linux <qat-linux@intel.com>,
"Cao, Yahui" <yahui.cao@intel.com>
Subject: Re: [PATCH 10/10] vfio/qat: Add vfio_pci driver for Intel QAT VF devices
Date: Wed, 21 Feb 2024 09:18:56 -0400 [thread overview]
Message-ID: <20240221131856.GS13330@nvidia.com> (raw)
In-Reply-To: <DM4PR11MB550223E2A68FA6A95970873888572@DM4PR11MB5502.namprd11.prod.outlook.com>
On Wed, Feb 21, 2024 at 08:44:31AM +0000, Zeng, Xin wrote:
> On Wednesday, February 21, 2024 1:03 AM, Jason Gunthorpe wrote:
> > On Tue, Feb 20, 2024 at 03:53:08PM +0000, Zeng, Xin wrote:
> > > On Tuesday, February 20, 2024 9:25 PM, Jason Gunthorpe wrote:
> > > > To: Zeng, Xin <xin.zeng@intel.com>
> > > > Cc: Yishai Hadas <yishaih@nvidia.com>; herbert@gondor.apana.org.au;
> > > > alex.williamson@redhat.com; shameerali.kolothum.thodi@huawei.com;
> > Tian,
> > > > Kevin <kevin.tian@intel.com>; linux-crypto@vger.kernel.org;
> > > > kvm@vger.kernel.org; qat-linux <qat-linux@intel.com>; Cao, Yahui
> > > > <yahui.cao@intel.com>
> > > > Subject: Re: [PATCH 10/10] vfio/qat: Add vfio_pci driver for Intel QAT VF
> > devices
> > > >
> > > > On Sat, Feb 17, 2024 at 04:20:20PM +0000, Zeng, Xin wrote:
> > > >
> > > > > Thanks for this information, but this flow is not clear to me why it
> > > > > cause deadlock. From this flow, CPU0 is not waiting for any resource
> > > > > held by CPU1, so after CPU0 releases mmap_lock, CPU1 can continue
> > > > > to run. Am I missing something?
> > > >
> > > > At some point it was calling copy_to_user() under the state
> > > > mutex. These days it doesn't.
> > > >
> > > > copy_to_user() would nest the mm_lock under the state mutex which is
> > a
> > > > locking inversion.
> > > >
> > > > So I wonder if we still have this problem now that the copy_to_user()
> > > > is not under the mutex?
> > >
> > > In protocol v2, we still have the scenario in precopy_ioctl where
> > copy_to_user is
> > > called under state_mutex.
> >
> > Why? Does mlx5 do that? It looked Ok to me:
> >
> > mlx5vf_state_mutex_unlock(mvdev);
> > if (copy_to_user((void __user *)arg, &info, minsz))
> > return -EFAULT;
>
> Indeed, thanks, Jason. BTW, is there any reason why was "deferred_reset" mode
> still implemented in mlx5 driver given this deadlock condition has been avoided
> with migration protocol v2 implementation.
I do not remember. Yishai?
Jason
next prev parent reply other threads:[~2024-02-21 13:18 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-01 15:33 [PATCH 00/10] crypto: qat - enable SRIOV VF live migration for Xin Zeng
2024-02-01 15:33 ` [PATCH 01/10] crypto: qat - adf_get_etr_base() helper Xin Zeng
2024-02-01 15:33 ` [PATCH 02/10] crypto: qat - relocate and rename 4xxx PF2VM definitions Xin Zeng
2024-02-01 15:33 ` [PATCH 03/10] crypto: qat - move PFVF compat checker to a function Xin Zeng
2024-02-01 15:33 ` [PATCH 04/10] crypto: qat - relocate CSR access code Xin Zeng
2024-02-01 15:33 ` [PATCH 05/10] crypto: qat - rename get_sla_arr_of_type() Xin Zeng
2024-02-01 15:33 ` [PATCH 06/10] crypto: qat - expand CSR operations for QAT GEN4 devices Xin Zeng
2024-02-01 15:33 ` [PATCH 07/10] crypto: qat - add bank save and restore flows Xin Zeng
2024-02-04 7:49 ` [EXTERNAL] " Kamlesh Gurudasani
2024-02-19 3:41 ` Wan, Siming
2024-02-01 15:33 ` [PATCH 08/10] crypto: qat - add interface for live migration Xin Zeng
2024-02-01 15:33 ` [PATCH 09/10] crypto: qat - implement " Xin Zeng
2024-02-01 15:33 ` [PATCH 10/10] vfio/qat: Add vfio_pci driver for Intel QAT VF devices Xin Zeng
2024-02-06 12:55 ` Jason Gunthorpe
2024-02-09 8:23 ` Zeng, Xin
2024-02-09 12:10 ` Jason Gunthorpe
2024-02-11 8:17 ` Yishai Hadas
2024-02-17 16:20 ` Zeng, Xin
2024-02-20 13:24 ` Jason Gunthorpe
2024-02-20 15:53 ` Zeng, Xin
2024-02-20 17:03 ` Jason Gunthorpe
2024-02-21 8:44 ` Zeng, Xin
2024-02-21 13:18 ` Jason Gunthorpe [this message]
2024-02-21 15:11 ` Yishai Hadas
2024-02-22 9:39 ` Yishai Hadas
2024-02-06 21:14 ` Alex Williamson
2024-02-09 16:16 ` Zeng, Xin
2024-02-08 12:17 ` Shameerali Kolothum Thodi
2024-02-13 13:08 ` Zeng, Xin
2024-02-13 14:55 ` Jason Gunthorpe
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=20240221131856.GS13330@nvidia.com \
--to=jgg@nvidia.com \
--cc=alex.williamson@redhat.com \
--cc=herbert@gondor.apana.org.au \
--cc=kevin.tian@intel.com \
--cc=kvm@vger.kernel.org \
--cc=linux-crypto@vger.kernel.org \
--cc=qat-linux@intel.com \
--cc=shameerali.kolothum.thodi@huawei.com \
--cc=xin.zeng@intel.com \
--cc=yahui.cao@intel.com \
--cc=yishaih@nvidia.com \
/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).