All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jason Gunthorpe via iommu <iommu@lists.linux-foundation.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: kvm@vger.kernel.org, rafael@kernel.org,
	David Airlie <airlied@linux.ie>,
	linux-pci@vger.kernel.org,
	Thierry Reding <thierry.reding@gmail.com>,
	Diana Craciun <diana.craciun@oss.nxp.com>,
	Dmitry Osipenko <digetx@gmail.com>, Will Deacon <will@kernel.org>,
	Ashok Raj <ashok.raj@intel.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Christoph Hellwig <hch@infradead.org>,
	Stuart Yoder <stuyoder@gmail.com>,
	Kevin Tian <kevin.tian@intel.com>,
	Chaitanya Kulkarni <kch@nvidia.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Cornelia Huck <cohuck@redhat.com>,
	linux-kernel@vger.kernel.org, Li Yang <leoyang.li@nxp.com>,
	iommu@lists.linux-foundation.org,
	Jacob jun Pan <jacob.jun.pan@intel.com>,
	Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH v1 1/8] iommu: Add iommu_group_replace_domain()
Date: Mon, 14 Feb 2022 08:45:18 -0400	[thread overview]
Message-ID: <20220214124518.GU4160@nvidia.com> (raw)
In-Reply-To: <43f2fc07-19ea-53a4-af86-a9192a950c96@arm.com>

On Mon, Feb 14, 2022 at 12:09:36PM +0000, Robin Murphy wrote:
> On 2022-01-06 02:20, Lu Baolu wrote:
> > Expose an interface to replace the domain of an iommu group for frameworks
> > like vfio which claims the ownership of the whole iommu group.
> 
> But if the underlying point is the new expectation that
> iommu_{attach,detach}_device() operate on the device's whole group where
> relevant, why should we invent some special mechanism for VFIO to be
> needlessly inconsistent?
> 
> I said before that it's trivial for VFIO to resolve a suitable device if it
> needs to; by now I've actually written the patch ;)
> 
> https://gitlab.arm.com/linux-arm/linux-rm/-/commit/9f37d8c17c9b606abc96e1f1001c0b97c8b93ed5

Er, how does locking work there? What keeps busdev from being
concurrently unplugged? How can iommu_group_get() be safely called on
this pointer?

All of the above only works normally inside a probe/remove context
where the driver core is blocking concurrent unplug and descruction.

I think I said this last time you brought it up that lifetime was the
challenge with this idea.

Jason
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@nvidia.com>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>,
	Joerg Roedel <joro@8bytes.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	Christoph Hellwig <hch@infradead.org>,
	Kevin Tian <kevin.tian@intel.com>,
	Ashok Raj <ashok.raj@intel.com>,
	kvm@vger.kernel.org, rafael@kernel.org,
	David Airlie <airlied@linux.ie>,
	linux-pci@vger.kernel.org,
	Thierry Reding <thierry.reding@gmail.com>,
	Diana Craciun <diana.craciun@oss.nxp.com>,
	Dmitry Osipenko <digetx@gmail.com>, Will Deacon <will@kernel.org>,
	Stuart Yoder <stuyoder@gmail.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Chaitanya Kulkarni <kch@nvidia.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Cornelia Huck <cohuck@redhat.com>,
	linux-kernel@vger.kernel.org, Li Yang <leoyang.li@nxp.com>,
	iommu@lists.linux-foundation.org,
	Jacob jun Pan <jacob.jun.pan@intel.com>,
	Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH v1 1/8] iommu: Add iommu_group_replace_domain()
Date: Mon, 14 Feb 2022 08:45:18 -0400	[thread overview]
Message-ID: <20220214124518.GU4160@nvidia.com> (raw)
In-Reply-To: <43f2fc07-19ea-53a4-af86-a9192a950c96@arm.com>

On Mon, Feb 14, 2022 at 12:09:36PM +0000, Robin Murphy wrote:
> On 2022-01-06 02:20, Lu Baolu wrote:
> > Expose an interface to replace the domain of an iommu group for frameworks
> > like vfio which claims the ownership of the whole iommu group.
> 
> But if the underlying point is the new expectation that
> iommu_{attach,detach}_device() operate on the device's whole group where
> relevant, why should we invent some special mechanism for VFIO to be
> needlessly inconsistent?
> 
> I said before that it's trivial for VFIO to resolve a suitable device if it
> needs to; by now I've actually written the patch ;)
> 
> https://gitlab.arm.com/linux-arm/linux-rm/-/commit/9f37d8c17c9b606abc96e1f1001c0b97c8b93ed5

Er, how does locking work there? What keeps busdev from being
concurrently unplugged? How can iommu_group_get() be safely called on
this pointer?

All of the above only works normally inside a probe/remove context
where the driver core is blocking concurrent unplug and descruction.

I think I said this last time you brought it up that lifetime was the
challenge with this idea.

Jason

  reply	other threads:[~2022-02-14 12:45 UTC|newest]

Thread overview: 88+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-06  2:20 [PATCH v1 0/8] Scrap iommu_attach/detach_group() interfaces Lu Baolu
2022-01-06  2:20 ` Lu Baolu
2022-01-06  2:20 ` [PATCH v1 1/8] iommu: Add iommu_group_replace_domain() Lu Baolu
2022-01-06  2:20   ` Lu Baolu
2022-01-06 17:06   ` Jason Gunthorpe via iommu
2022-01-06 17:06     ` Jason Gunthorpe
2022-01-07  0:26     ` Lu Baolu
2022-01-07  0:26       ` Lu Baolu
2022-02-14 12:09   ` Robin Murphy
2022-02-14 12:09     ` Robin Murphy
2022-02-14 12:45     ` Jason Gunthorpe via iommu [this message]
2022-02-14 12:45       ` Jason Gunthorpe
2022-02-14 14:10       ` Robin Murphy
2022-02-14 14:10         ` Robin Murphy
2022-02-14 14:56         ` Jason Gunthorpe via iommu
2022-02-14 14:56           ` Jason Gunthorpe
2022-02-14 16:38           ` Robin Murphy
2022-02-14 16:38             ` Robin Murphy
2022-02-14 17:25             ` Jason Gunthorpe via iommu
2022-02-14 17:25               ` Jason Gunthorpe
2022-01-06  2:20 ` [PATCH v1 2/8] vfio/type1: Use iommu_group_replace_domain() Lu Baolu
2022-01-06  2:20   ` Lu Baolu
2022-01-06  2:20 ` [PATCH v1 3/8] iommu: Extend iommu_at[de]tach_device() for multi-device groups Lu Baolu
2022-01-06  2:20   ` Lu Baolu
2022-01-06 17:22   ` Jason Gunthorpe via iommu
2022-01-06 17:22     ` Jason Gunthorpe
2022-01-07  1:14     ` Lu Baolu
2022-01-07  1:14       ` Lu Baolu
2022-01-07  1:19       ` Jason Gunthorpe via iommu
2022-01-07  1:19         ` Jason Gunthorpe
2022-02-14 11:39   ` Joerg Roedel
2022-02-14 11:39     ` Joerg Roedel
2022-02-14 13:03     ` Jason Gunthorpe via iommu
2022-02-14 13:03       ` Jason Gunthorpe
2022-02-14 14:39       ` Joerg Roedel
2022-02-14 14:39         ` Joerg Roedel
2022-02-14 15:18         ` Robin Murphy
2022-02-14 15:18           ` Robin Murphy
2022-02-14 15:46           ` Jason Gunthorpe via iommu
2022-02-14 15:46             ` Jason Gunthorpe
2022-02-15  8:58             ` Joerg Roedel
2022-02-15  8:58               ` Joerg Roedel
2022-02-15 13:47               ` Jason Gunthorpe via iommu
2022-02-15 13:47                 ` Jason Gunthorpe
2022-02-16  6:28                 ` Lu Baolu
2022-02-16  6:28                   ` Lu Baolu
2022-02-16 13:54                   ` Jason Gunthorpe via iommu
2022-02-16 13:54                     ` Jason Gunthorpe
2022-01-06  2:20 ` [PATCH v1 4/8] drm/tegra: Use iommu_attach/detatch_device() Lu Baolu
2022-01-06  2:20   ` Lu Baolu
2022-01-06  2:20 ` [PATCH v1 5/8] iommu/amd: Use iommu_attach/detach_device() Lu Baolu
2022-01-06  2:20   ` Lu Baolu
2022-01-06 14:33   ` Jason Gunthorpe via iommu
2022-01-06 14:33     ` Jason Gunthorpe
2022-01-07  0:23     ` Lu Baolu
2022-01-07  0:23       ` Lu Baolu
2022-02-14 11:27     ` Joerg Roedel
2022-02-14 11:27       ` Joerg Roedel
2022-02-14 13:15       ` Jason Gunthorpe via iommu
2022-02-14 13:15         ` Jason Gunthorpe
2022-02-14 13:40         ` Joerg Roedel
2022-02-14 13:40           ` Joerg Roedel
2022-02-14 14:02           ` Jason Gunthorpe via iommu
2022-02-14 14:02             ` Jason Gunthorpe
2022-02-14 14:23             ` Joerg Roedel
2022-02-14 14:23               ` Joerg Roedel
2022-02-14 15:00               ` Jason Gunthorpe via iommu
2022-02-14 15:00                 ` Jason Gunthorpe
2022-02-15  9:11                 ` Joerg Roedel
2022-02-15  9:11                   ` Joerg Roedel
2022-02-15 13:02                   ` Robin Murphy
2022-02-15 13:02                     ` Robin Murphy
2022-02-15 14:37                   ` Jason Gunthorpe via iommu
2022-02-15 14:37                     ` Jason Gunthorpe
2022-01-06  2:20 ` [PATCH v1 6/8] gpu/host1x: " Lu Baolu
2022-01-06  2:20   ` Lu Baolu
2022-01-06 15:35   ` Jason Gunthorpe via iommu
2022-01-06 15:35     ` Jason Gunthorpe
2022-01-07  0:35     ` Lu Baolu
2022-01-07  0:35       ` Lu Baolu
2022-01-07  0:48       ` Jason Gunthorpe via iommu
2022-01-07  0:48         ` Jason Gunthorpe
2022-01-07  1:19         ` Lu Baolu
2022-01-07  1:19           ` Lu Baolu
2022-01-06  2:20 ` [PATCH v1 7/8] media: staging: media: tegra-vde: " Lu Baolu
2022-01-06  2:20   ` Lu Baolu
2022-01-06  2:20 ` [PATCH v1 8/8] iommu: Remove iommu_attach/detach_group() Lu Baolu
2022-01-06  2:20   ` Lu Baolu

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=20220214124518.GU4160@nvidia.com \
    --to=iommu@lists.linux-foundation.org \
    --cc=airlied@linux.ie \
    --cc=alex.williamson@redhat.com \
    --cc=ashok.raj@intel.com \
    --cc=bhelgaas@google.com \
    --cc=cohuck@redhat.com \
    --cc=dan.j.williams@intel.com \
    --cc=daniel@ffwll.ch \
    --cc=diana.craciun@oss.nxp.com \
    --cc=digetx@gmail.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=hch@infradead.org \
    --cc=jacob.jun.pan@intel.com \
    --cc=jgg@nvidia.com \
    --cc=jonathanh@nvidia.com \
    --cc=kch@nvidia.com \
    --cc=kevin.tian@intel.com \
    --cc=kvm@vger.kernel.org \
    --cc=leoyang.li@nxp.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=rafael@kernel.org \
    --cc=robin.murphy@arm.com \
    --cc=stuyoder@gmail.com \
    --cc=thierry.reding@gmail.com \
    --cc=will@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.