Message-ID: <1401309923.2412.71.camel@ul30vt.home>
Date:	Wed, 28 May 2014 14:45:23 -0600
From:	Alex Williamson <alex.williamson@...hat.com>
To:	Bjorn Helgaas <bhelgaas@...gle.com>
Cc:	linux-pci@...r.kernel.org, iommu@...ts.linux-foundation.org,
	acooks@...il.com, linux-kernel@...r.kernel.org, eddy0596@...il.com,
	linux@...izon.com
Subject: Re: [PATCH v4 00/16] PCI/iommu: Fix DMA alias problems

On Wed, 2014-05-28 at 14:29 -0600, Bjorn Helgaas wrote:
> On Thu, May 22, 2014 at 05:07:23PM -0600, Alex Williamson wrote:
> > For testing, this version can be found in my git tree:
> > 
> > git://github.com/awilliam/linux-vfio.git dma-alias-v4
> > 
> > Please report any issues.
> > 
> > v4:
> >  - Change dma_func_alias to dma_alias_devfn, holding a single
> >    devfn to alias, thereby supporting aliases to the wrong slot.
> >    The DMA alias iterator is easily changed, but IOMMU grouping
> >    requires significant rework.  This is now done in IOMMU code
> >    rather than PCI code.
> > 
> >  - AMD-Vi - try to incorporate IVRS aliases dynamically into
> >    PCI alias quirks to make sure that our grouping remains the
> >    same.  Potentially this could end up reporting BIOS aliases
> >    that we can add to our list of quirks.
> > 
> > v3:
> >  - Found several instances where I had PCI_SLOT when I meant
> >    PCI_FUNC.  Thanks to Andrew for spotting this.  This should
> >    fix the problem he was having with Ricoh quirks.  We also
> >    pruned down the func0 quirks to only those that we know are
> >    needed.  We can always add them back later.
> > 
> >  - Found a case in intel-iommu of using dev_is_pci() where I
> >    really wanted !dev_is_pci().  Fixed.
> > 
> > v2:
> >  - Several new Marvell controllers added to quirks.  There's been
> >    a lot of success reported with this series in
> >    https://bugzilla.kernel.org/show_bug.cgi?id=42679
> > 
> >  - Add quirk for ASMedia and Tundra PCIe-to-PCI bridges that do
> >    not expose a PCIe capability.  These have been shown to use
> >    the standard PCIe-to-PCI bridge requester ID.
> > 
> >  - Fix copy/paste duplicate Ricoh quirk ID
> > 
> >  - Fixed AMD IOMMU for the "ghost" function case where the DMA
> >    alias is for an absent device.  The iommu rlookup table and
> >    data fields need to be initializes.
> > 
> >  - Fixed Intel interrupt remapping, I wasn't passing the target
> >    bus number, only the alias bus number.
> > 
> > These patches are split across PCI and IOMMU, but I've front-loaded
> > all of the PCI infrastructure so that the first 7 patches can be
> > applied to PCI-core, the IOMMU maintainers can pickup their patches,
> > then we can finish with dead code removal.  Bjorn might also be
> > willing to carry the IOMMU changes if the maintainers want to ack
> > them.
> 
> I put 1-7 on a pci/iommu branch for v3.16.  I'm happy to include the rest,
> too, given acks from Joerg and David.  Or if they prefer to take them all,
> which might be easier than coordinating two trees, especially since there's
> PCI stuff at the beginning and end, here's my ack for the PCI bits (patches
> 1-7 and 15-16):
> 
>     Acked-by: Bjorn Helgaas <bhelgaas@...gle.com>

Awesome, thanks!

> If you want to send me updated changelogs for patches 5 & 6, I'll drop
> those in.

Yep, I'll send changelog updates for 5 & 6 in a few minutes.

> Didn't you have more testing reports?  I see George's, but I thought there
> were some others, too.

I also see:

https://lkml.org/lkml/2014/5/28/24
Tested-by: Pat Erley <pat-lkml@...ey.org>

There are several reports of success in the bzs, but I don't see any
official tested-by tags there.  Thanks,

Alex

> > Original description:
> > 
> > This series attempts to fix a couple issues we've had outstanding in
> > the PCI/IOMMU code for a while.  The first issue is with devices that
> > use the wrong requester ID for DMA transactions.  We already have a
> > sort of half-baked attempt to fix this for several Ricoh devices, but
> > the fix only helps them be useful through IOMMU groups, not the
> > general DMA case.  There are also several Marvell devices which use
> > use a different wrong requester ID and don't even fit into the DMA
> > source idea.  This series creates a DMA alias iterator that will
> > step through each possible alias of a device, allowing IOMMUs to
> > insert mappings for both the device and its aliases.
> > 
> > Hand-in-hand with this is our broken pci_find_upstream_pcie_bridge()
> > function, which is known to blowup when it finds itself suddenly at
> > a PCIe device without crossing a PCIe-to-PCI bridge (as identified by
> > the PCIe capability).  It also likes to make the invalid assumption
> > that a PCIe device never has its requester ID masked by any usptream
> > bus.  We can fix this using the above new DMA alias iterator, since
> > that's effectively what this function was meant to do.
> > 
> > Finally, with all these helpers, it makes sense to consolidate code
> > for determining IOMMU groups.  The first step in finding the root
> > of a group is finding the final upstream DMA alias for the device,
> > then applying additional ACS rules and incorporating device specific
> > aliases.  As this is all common to PCI, create a single implementation
> > and remove piles of code from the individual IOMMU drivers.
> > 
> > This series allows devices like the Marvell 88SE9123 to finally work
> > on Linux with either AMD-Vi or VT-d enabled on the box.  I've
> > collected device IDs from various bugs to support as many SKUs of
> > these devices as possible, but I'm sure there are others that I've
> > missed.
> > 
> > This should also enable motherboards with an onboard ASmedia
> > ASM1083/1085 PCIe-to-PCI bridge to work with VT-d enabled.  I've
> > acquired an adapter board with this chip, but it actually exposes
> > a PCIe capability, unlike most of the onboard controllers.  Therefore
> > I expect this series will fix the WARN_ON currently hit during boot,
> > but there's a 50/50 chance whether the device behaves like a PCI
> > bridge or a PCIe bridge with regard to the requester ID that it uses
> > to take ownership of the transaction.  If it turns out to use the
> > PCIe bridge model, I expect we can quirk it using a dev_flags bit
> > to identify a PCI bridge that takes ownership as if it was a PCIe
> > bridge.
> > 
> > Please test and provide feedback.  I expect IOMMU group topology
> > should not change from this series, but if a case is found where it
> > does, please share.  Also, if there are additional quirks we need
> > to add, please either file new or add to the existing bugs.  Thanks,
> > 
> > Alex
> > 
> > ---
> > 
> > Alex Williamson (16):
> >       PCI: Add DMA alias iterator
> >       PCI: define pci_dev_flags as bit shifts
> >       PCI: quirk pci_for_each_dma_alias()
> >       PCI: quirk dma_alias_devfn for Ricoh devices
> >       PCI: quirk dma_alias_devfn for Marvell devices
> >       PCI: Quirk pci_for_each_dma_alias() for bridges
> >       PCI: Add quirks for ASMedia and Tundra bridges
> >       iommu: Create central IOMMU group lookup/creation interface
> >       iommu/amd: Update to use PCI DMA aliases
> >       iommu/amd: Use iommu_group_get_for_dev()
> >       iommu/intel: Use iommu_group_get_for_dev()
> >       iommu/intel: Update to use PCI DMA aliases
> >       iommu/fsl: Use iommu_group_get_for_dev() for IOMMU groups
> >       iommu: Remove pci.h
> >       PCI: Remove pci_find_upstream_pcie_bridge()
> >       PCI: Remove pci_get_dma_source()
> > 
> > 
> >  drivers/iommu/amd_iommu.c           |  214 +++++++-----------------
> >  drivers/iommu/amd_iommu_types.h     |    1 
> >  drivers/iommu/fsl_pamu_domain.c     |   66 --------
> >  drivers/iommu/intel-iommu.c         |  307 +++++++++++++----------------------
> >  drivers/iommu/intel_irq_remapping.c |   55 ++++--
> >  drivers/iommu/iommu.c               |  181 +++++++++++++++++++++
> >  drivers/iommu/pci.h                 |   29 ---
> >  drivers/pci/quirks.c                |  116 ++++++++-----
> >  drivers/pci/search.c                |  104 +++++++++---
> >  include/linux/iommu.h               |    1 
> >  include/linux/pci.h                 |   31 +---
> >  11 files changed, 557 insertions(+), 548 deletions(-)
> >  delete mode 100644 drivers/iommu/pci.h



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