Date:	Fri, 5 Apr 2013 12:44:12 +0800
From:	Andrew Cooks <acooks@...il.com>
To:	Pat Erley <pat-lkml@...ey.org>
Cc:	"open list:INTEL IOMMU, (VT-d)" <iommu@...ts.linux-foundation.org>,
	Alex Williamson <alex.williamson@...hat.com>,
	"David Woodhouse (supporter:INTEL IOMMU (VT-d))" 
	<dwmw2@...radead.org>,
	"list@...ote.erley.org:PCI SUBSYSTEM" <linux-pci@...r.kernel.org>,
	open list <linux-kernel@...r.kernel.org>, jforbes@...hat.com
Subject: Ricoh DMAR bug returns? (WAS Re: [PATCH v4] Quirk for buggy dma
 source tags with Intel IOMMU.)

On Tue, Apr 2, 2013 at 11:47 PM, Pat Erley <pat-lkml@...ey.org> wrote:
> On 04/02/2013 10:50 AM, Andrew Cooks wrote:
>>
>> On 2 Apr 2013 15:37, "Pat Erley" <pat-lkml@...ey.org
>> <mailto:pat-lkml@...ey.org>> wrote:
>>  >
>>  > On 03/07/2013 09:35 PM, Andrew Cooks wrote:
>>  >>
>>  >> --- a/drivers/pci/quirks.c
>>  >> +++ b/drivers/pci/quirks.c
>>  >>
>>  >> +/* Table of multiple (ghost) source functions. This is similar to the
>>  >> + * translated sources above, but with the following differences:
>>  >> + * 1. the device may use multiple functions as DMA sources,
>>  >> + * 2. these functions cannot be assumed to be actual devices,
>> they're simply
>>  >> + * incorrect DMA tags.
>>  >> + * 3. the specific ghost function for a request can not always be
>> predicted.
>>  >> + * For example, the actual device could be xx:yy.1 and it could use
>>  >> + * both 0 and 1 for different requests, with no obvious way to tell
>> when
>>  >> + * DMA will be tagged as comming from xx.yy.0 and and when it will
>> be tagged
>>  >> + * as comming from xx.yy.1.
>>  >> + * The bitmap contains all of the functions used in DMA tags,
>> including the
>>  >> + * actual device.
>>  >> + * See https://bugzilla.redhat.com/show_bug.cgi?id=757166,
>>  >> + * https://bugzilla.kernel.org/show_bug.cgi?id=42679
>>  >> + * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1089768
>>  >> + */
>>  >> +static const struct pci_dev_dma_multi_func_sources {
>>  >> +       u16 vendor;
>>  >> +       u16 device;
>>  >> +       u8 func_map;    /* bit map. lsb is fn 0. */
>>  >> +} pci_dev_dma_multi_func_sources[] = {
>>  >> +       { PCI_VENDOR_ID_MARVELL_2, 0x9123, (1<<0)|(1<<1)},
>>  >> +       { PCI_VENDOR_ID_MARVELL_2, 0x9125, (1<<0)|(1<<1)},
>>  >> +       { PCI_VENDOR_ID_MARVELL_2, 0x9128, (1<<0)|(1<<1)},
>>  >> +       { PCI_VENDOR_ID_MARVELL_2, 0x9130, (1<<0)|(1<<1)},
>>  >> +       { PCI_VENDOR_ID_MARVELL_2, 0x9143, (1<<0)|(1<<1)},
>>  >> +       { PCI_VENDOR_ID_MARVELL_2, 0x9172, (1<<0)|(1<<1)},
>>  >> +       { 0 }
>>  >> +};
>>  >
>>  >
>>  > Adding another buggy device.  I have a Ricoh multifunction device:
>>  >
>>  > 17:00.0 SD Host controller: Ricoh Co Ltd MMC/SD Host Controller (rev
>> 01)
>>  > 17:00.3 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 PCIe IEEE 1394
>>  >         Controller (rev 01)
>>  >
>>  > 17:00.0 0805: 1180:e822 (rev 01)
>>  > 17:00.3 0c00: 1180:e832 (rev 01)
>>  >
>>
>> The Ricoh device issue has been known for some time and a quirk has been
>> available since commit 12ea6cad1c7d046 in June 2012.  It's slightly
>> different than the problem this patch tries to work around [1].
>
>
> Hmm, I've had this problem with many recent (vanilla) kernels, up to and
> including 3.9-rc5
>
>
>>  > that adding entries for also fixed booting.  I don't have any SD
>> cards or firewire devices handy to test that they work, but the system
>> now boots, which was not the case without your patch and IOMMU/DMAR
>> enabled.
>>
>> That is really strange. Could you tell us what kernel version you tested
>> and provide dmesg output?
>
>
> I'll capture a vanilla 3.8.5 boot without any patches and iommu=off, then
> try to find another machine to catch what I can of a netconsole boot with
> iommu=on.  What's the preferred way to send these?  pastebin links?
>
> I'd been running the 'dirty' fix that's in the redhat bugzilla entry.  I
> checked my .config and have CONFIG_PCI_QUIRKS=y, and verified my devices are
> in the quirks table for the pci_func_0_dma_source fixup.
>
Do you mean that even though your hardware is specifically listed in
the quirk table, the quirk simply hasn't worked for you? That would be
unfortunate, to say the least.

The fedora kernel included a separate patch for this issue until
recently (see https://bugzilla.redhat.com/show_bug.cgi?id=880051).  It
basically just disabled DMAR when the Ricoh device is present, the
same as the patch to the mailing list you mentioned.

Is the dirty fix you're referring to comment 7?
https://bugzilla.redhat.com/show_bug.cgi?id=605888#c7

>>
>> [1] In the Ricoh case, multiple functions are used for real devices and
>> the bug is that these devices all use function 0 during DMA. In this
>> particular case, I'd expect the FireWire device 17:00.3 to issue DMA
>> from the SD Host Controller address 17:00.0. The quirk is not too much
>> of a terrible hack - it's a fairly simple translation.
>>
>> In the Marvell case, the real device uses DMA source tags that don't
>> actually belong to any visible devices. The quirk to make this work is
>> more invasive, not nearly as elegant and has not attracted much
>> enthusiasm from subsystem maintainers, though I'm still hopeful that a
>> quirk will be merged in some form or another.
>>
>
> Thanks for explaining the difference!
>
> Pat
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