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Message-ID: <1373300262.2602.22.camel@ul30vt.home>
Date: Mon, 08 Jul 2013 10:17:42 -0600
From: Alex Williamson <alex.williamson@...hat.com>
To: bhelgaas@...gle.com
Cc: linux-pci@...r.kernel.org, joro@...tes.org,
andihartmann@...19freenet.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 0/3] pci: ACS fixes & quirks
Ping. Comments?
On Thu, 2013-06-27 at 16:39 -0600, Alex Williamson wrote:
> v2:
>
> Revised patch 1/ to match comments from Bjorn. PCIe event collectors
> and PCIe-to-PCI bridges now indicate that they do not support ACS.
> I've reached out to try to get clarification on this, but I think it's
> reasonable to proceed with a conservative approach until then. I also
> added PCI-to-PCIe bridges for the sake of being complete. Also added
> more comments about the purpose and behavior of pci_acs_enabled(). If
> I've overlooked anything else that needs to be addressed, please let
> me know.
>
> Patch 2/ had no comments, it's unchanged.
>
> Patch 3/ is added. This was sent as an RFC nearly a year ago and
> Joerg confirmed for us that these devices do not support p2p on AMD
> systems with AMD IOMMU. We can't simply use iommu_present() to test
> for an IOMMU because it's setup just after we need this function.
> Instead we test for the ACPI IVRS table that describes the IOMMU. It
> would probably suffice to skip an actual AMD IOMMU check, but I don't
> want it to later come bite us if these ASICs get re-used, maybe with
> a different IOMMU, and don't make the same guarantees.
>
> Joerg, I was also curious back when we investigated this patch if the
> same rules hold true for these other southbridge devices:
>
> 1002:43a0 SB700/SB800/SB900 PCI to PCI bridge (PCIE port 0)
> 1002:43a1 SB700/SB800/SB900 PCI to PCI bridge (PCIE port 1)
> 1002:43a2 SB900 PCI to PCI bridge (PCIE port 2)
> 1002:43a3 SB900 PCI to PCI bridge (PCIE port 3)
>
> If you remember or have contacts to poke, I'd be happy to follow-up
> with another patch to add them. Thanks,
>
> Alex
>
> ---
>
> Alex Williamson (3):
> pci: Fix flaw in pci_acs_enabled()
> pci: Differentiate ACS controllable from enabled
> pci: ACS quirk for AMD southbridge
>
>
> drivers/pci/pci.c | 93 +++++++++++++++++++++++++++++++++++++++++---------
> drivers/pci/quirks.c | 50 +++++++++++++++++++++++++++
> 2 files changed, 127 insertions(+), 16 deletions(-)
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