linux-kernel - Re: [PATCH v3 08/15] iommu/amd: Use pci_find_dma_isolation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20140514103449.GE6026@8bytes.org>
Date:	Wed, 14 May 2014 12:34:50 +0200
From:	Joerg Roedel <joro@...tes.org>
To:	Alex Williamson <alex.williamson@...hat.com>
Cc:	linux-pci@...r.kernel.org, iommu@...ts.linux-foundation.org,
	bhelgaas@...gle.com, acooks@...il.com,
	linux-kernel@...r.kernel.org, linux@...izon.com
Subject: Re: [PATCH v3 08/15] iommu/amd: Use pci_find_dma_isolation_root()
 for IOMMU groups

On Sat, May 10, 2014 at 09:03:11AM -0600, Alex Williamson wrote:
> The expectation is that the kernel and IVRS will produce the same
> result for topology based aliases while the kernel will also include
> device specific DMA quirks.

Is that expectation really true? There are PCIe devices out there that
don't use their own device-id for requests but another one that isn't
even visible as a PCI device (so the kernel has no pci_dev structure for
it). The IVRS table contains such information, but I am not sure whether
the PCI core finds the right requestor-id for those devices.

I've seen this on PCIe cards that where the vendor just used an PCI-X
chip with a PCIe-to-PCI-X bridge on the card. The PCI-X device is
visible for the OS but uses the requestor-id of the invisible bridge.

	Joerg

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/