linux-kernel - RE: [PATCH v2] PCI: Add ATS-disable quirk for AMD Stoney GPUs

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: <BN6PR12MB1652DF4130FC792B71DD9974F7C00@BN6PR12MB1652.namprd12.prod.outlook.com>
Date:   Thu, 15 Jun 2017 18:13:49 +0000
From:   "Deucher, Alexander" <Alexander.Deucher@....com>
To:     'Samuel Sieb' <samuel@...b.net>, Joerg Roedel <jroedel@...e.de>,
        "Bjorn Helgaas" <bhelgaas@...gle.com>
CC:     "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Daniel Drake <drake@...lessm.com>,
        David Woodhouse <dwmw2@...radead.org>
Subject: RE: [PATCH v2] PCI: Add ATS-disable quirk for AMD Stoney GPUs

> -----Original Message-----
> From: Samuel Sieb [mailto:samuel@...b.net]
> Sent: Thursday, June 15, 2017 1:02 PM
> To: Joerg Roedel; Bjorn Helgaas
> Cc: linux-pci@...r.kernel.org; linux-kernel@...r.kernel.org; Daniel Drake;
> Deucher, Alexander; David Woodhouse
> Subject: Re: [PATCH v2] PCI: Add ATS-disable quirk for AMD Stoney GPUs
> 
> On 06/15/2017 07:04 AM, Joerg Roedel wrote:
> > Hi Bjorn,
> >
> > On Fri, Apr 07, 2017 at 04:32:18PM +0200, Joerg Roedel wrote:
> >> From: Joerg Roedel <jroedel@...e.de>
> >>
> >> ATS is broken on this hardware and causes IOMMU stalls and
> >> system failure. Disable ATS on these devices to make them
> >> usable again with IOMMU enabled.
> >>
> >> Note that the commit in the Fixes-tag is not buggy, it
> >> just uncovers the problem in the hardware by increasing
> >> the ATS-flush rate.
> >>
> >> Fixes: b1516a14657a ('iommu/amd: Implement flush queue')
> >> Signed-off-by: Joerg Roedel <jroedel@...e.de>
> >> ---
> >>   drivers/pci/quirks.c | 19 +++++++++++++++++++
> >>   1 file changed, 19 insertions(+)
> >
> > Any more objections on this patch? Please let me know if you want to
> > have something changed.
> 
> The other patch seems to fix this issue without disabling ATS.  Isn't
> that better?

I talked to our validation team and ATS was validated on Stoney, so this patch is just working around something else.  The other patch fixes it and is a valid optimization (it should be applied eventually), but apparently the current behavior is allowed even if it's now optimal.  I'm not really an ATS expert.

Alex