From: Will Deacon <will@kernel.org>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
iommu@lists.linux-foundation.org,
Robin Murphy <robin.murphy@arm.com>,
LKML <linux-kernel@vger.kernel.org>,
Saravana Kannan <saravanak@google.com>
Subject: Re: [PATCH 0/7] iommu: Permit modular builds of ARM SMMU[v3] drivers
Date: Fri, 1 Nov 2019 17:21:46 +0000 [thread overview]
Message-ID: <20191101172145.GA3983@willie-the-truck> (raw)
In-Reply-To: <20191031193758.GA2607492@lophozonia>
Hi Jean-Philippe,
Quick question while you figure out the devlink stuff with Saravana...
On Thu, Oct 31, 2019 at 08:37:58PM +0100, Jean-Philippe Brucker wrote:
> On Wed, Oct 30, 2019 at 05:57:44PM -0700, Saravana Kannan via iommu wrote:
> > > > > Obviously you need to be careful about using IOMMU drivers as modules,
> > > > > since late loading of the driver for an IOMMU serving active DMA masters
> > > > > is going to end badly in many cases. On Android, we're using device links
> > > > > to ensure that the IOMMU probes first.
> > > >
> > > > Out of curiosity, which device links are those? Clearly not the RPM links
> > > > created by the IOMMU drivers themselves... Is this some special Android
> > > > magic, or is there actually a chance of replacing all the
> > > > of_iommu_configure() machinery with something more generic?
> > >
> > > I'll admit that I haven't used them personally yet, but I'm referring to
> > > this series from Saravana [CC'd]:
> > >
> > > https://lore.kernel.org/linux-acpi/20190904211126.47518-1-saravanak@google.com/
> > >
> > > which is currently sitting in linux-next now that we're upstreaming the
> > > "special Android magic" ;)
>
> Neat, I'm trying to do the same for virtio-iommu. It needs to be modular
> because it depends on the virtio transport, which distributions usually
> build as a module. So far I've been managing the device links in
> virtio-iommu's add_device() and remove_device() callbacks [1]. Since it
> relies on the existing probe deferral, I had to make a special case for
> virtio-iommu to avoid giving up after initcalls_done [2].
As far as symbols exported from the IOMMU and PCI layers, did you find you
needed anything on top of the stuff I'm exporting in patches 1 and 3?
Cheers,
Will
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next prev parent reply other threads:[~2019-11-01 17:21 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-30 14:51 [PATCH 0/7] iommu: Permit modular builds of ARM SMMU[v3] drivers Will Deacon
2019-10-30 14:51 ` [PATCH 1/7] drivers/iommu: Export core IOMMU API symbols to permit modular drivers Will Deacon
2019-10-30 14:51 ` [PATCH 2/7] iommu/of: Request ACS from the PCI core when configuring IOMMU linkage Will Deacon
2019-10-30 14:51 ` [PATCH 3/7] PCI: Export pci_ats_disabled() as a GPL symbol to modules Will Deacon
2019-10-30 20:30 ` Bjorn Helgaas
2019-10-30 14:51 ` [PATCH 4/7] Revert "iommu/arm-smmu: Make arm-smmu-v3 explicitly non-modular" Will Deacon
2019-10-30 14:51 ` [PATCH 5/7] iommu/arm-smmu-v3: Allow building as a module Will Deacon
2019-10-30 19:31 ` Joerg Roedel
2019-10-31 15:42 ` Will Deacon
2019-11-04 19:15 ` Jean-Philippe Brucker
2019-11-08 14:54 ` Will Deacon
2019-11-05 12:15 ` Joerg Roedel
2019-11-08 11:03 ` Will Deacon
2019-10-30 14:51 ` [PATCH 6/7] Revert "iommu/arm-smmu: Make arm-smmu explicitly non-modular" Will Deacon
2019-10-30 23:09 ` Jordan Crouse
2019-10-31 12:03 ` Will Deacon
2019-10-31 15:32 ` Jordan Crouse
2019-10-30 14:51 ` [PATCH 7/7] iommu/arm-smmu: Allow building as a module Will Deacon
2019-10-30 15:22 ` Rob Herring
2019-10-30 15:26 ` Will Deacon
2019-10-30 15:33 ` Robin Murphy
2019-11-04 19:34 ` Isaac J. Manjarres
2019-11-07 12:48 ` Will Deacon
2019-10-30 15:35 ` [PATCH 0/7] iommu: Permit modular builds of ARM SMMU[v3] drivers Robin Murphy
2019-10-30 15:54 ` Will Deacon
2019-10-31 0:57 ` Saravana Kannan via iommu
2019-10-31 19:37 ` Jean-Philippe Brucker
2019-10-31 23:34 ` Saravana Kannan via iommu
2019-11-01 10:27 ` John Garry
2019-11-01 21:13 ` Saravana Kannan via iommu
2019-11-04 12:16 ` John Garry
2019-11-04 13:29 ` Robin Murphy
2019-11-07 6:11 ` Saravana Kannan via iommu
2019-11-07 9:13 ` Jean-Philippe Brucker
2019-11-07 6:02 ` Saravana Kannan via iommu
2019-11-01 11:41 ` Jean-Philippe Brucker
2019-11-01 12:28 ` Lorenzo Pieralisi
2019-11-01 21:26 ` Saravana Kannan via iommu
2019-11-04 11:43 ` Lorenzo Pieralisi
2019-11-07 5:55 ` Saravana Kannan via iommu
2019-11-01 17:21 ` Will Deacon [this message]
2019-11-04 7:54 ` Jean-Philippe Brucker
2019-11-07 6:16 ` Saravana Kannan via iommu
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