From: Jason Gunthorpe <jgg@ziepe.ca>
To: Pranjal Shrivastava <praan@google.com>
Cc: Nicolin Chen <nicolinc@nvidia.com>,
iommu@lists.linux.dev, Will Deacon <will@kernel.org>,
Joerg Roedel <joro@8bytes.org>,
Robin Murphy <robin.murphy@arm.com>,
Mostafa Saleh <smostafa@google.com>,
Samiullah Khawaja <skhawaja@google.com>,
Daniel Mentz <danielmentz@google.com>,
Pasha Tatashin <pasha.tatashin@soleen.com>,
David Matlack <dmatlack@google.com>
Subject: Re: [PATCH rc v2] iommu/arm-smmu-v3: Fix inconsistent ATS state tracking
Date: Tue, 5 May 2026 13:11:26 -0300 [thread overview]
Message-ID: <afoWrn/RXxDmcHsS@ziepe.ca> (raw)
In-Reply-To: <afj0cyBZwkVLyIwK@google.com>
On Mon, May 04, 2026 at 07:33:07PM +0000, Pranjal Shrivastava wrote:
> > > The issue was exposed under heavy load when running a VFIO-based DMA map
> > > stress test: iova_stress [1]
> >
> > I wonder what's the real reason for pci_enable_ats() to fail:
> >
>
> Yes, It's the dev->is_virtfn case (the one you suspect below)
Oh.... This is a much larger problem then
The VF should not fail to enable ATS, that is a meaningful bug, I'm
not sure why are are just discovering this?
It looks like the PF unconditionally calls pci_prepare_ats() during
arm_smmu_probe_device(), so how does this happen:
> > if (dev->is_virtfn) {
> > pdev = pci_physfn(dev);
> > if (pdev->ats_stu != ps)
> > return -EINVAL; // maybe this one?
??
So, I think the right error handling for a case that shouldn't happen is
to fail the attachment not to try to continue it broken?
Jason
next prev parent reply other threads:[~2026-05-05 16:11 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-04 16:38 [PATCH rc v2] iommu/arm-smmu-v3: Fix inconsistent ATS state tracking Pranjal Shrivastava
2026-05-04 18:01 ` Nicolin Chen
2026-05-04 19:33 ` Pranjal Shrivastava
2026-05-04 20:03 ` Pranjal Shrivastava
2026-05-04 20:23 ` Nicolin Chen
2026-05-04 20:29 ` Pranjal Shrivastava
2026-05-04 20:51 ` Nicolin Chen
2026-05-04 20:40 ` Pranjal Shrivastava
2026-05-04 20:54 ` Nicolin Chen
2026-05-05 16:11 ` Jason Gunthorpe [this message]
2026-05-05 20:21 ` Nicolin Chen
2026-05-05 21:23 ` Pranjal Shrivastava
2026-05-05 21:44 ` Nicolin Chen
2026-05-05 22:06 ` Pranjal Shrivastava
2026-05-06 20:44 ` Samiullah Khawaja
2026-05-05 21:14 ` Pranjal Shrivastava
2026-05-05 22:32 ` Pranjal Shrivastava
2026-05-06 9:46 ` Jason Gunthorpe
2026-05-06 20:19 ` Pranjal Shrivastava
2026-05-06 22:03 ` Pranjal Shrivastava
2026-05-06 21:57 ` Pranjal Shrivastava
2026-05-06 22:04 ` Pranjal Shrivastava
2026-05-09 17:14 ` Jason Gunthorpe
2026-05-11 12:07 ` Pranjal Shrivastava
2026-05-11 14:16 ` Jason Gunthorpe
2026-05-11 16:07 ` Pranjal Shrivastava
2026-05-11 16:30 ` David Matlack
2026-05-11 16:57 ` Pranjal Shrivastava
2026-05-11 17:03 ` Jason Gunthorpe
2026-05-06 22:20 ` Samiullah Khawaja
2026-05-07 20:12 ` Pranjal Shrivastava
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=afoWrn/RXxDmcHsS@ziepe.ca \
--to=jgg@ziepe.ca \
--cc=danielmentz@google.com \
--cc=dmatlack@google.com \
--cc=iommu@lists.linux.dev \
--cc=joro@8bytes.org \
--cc=nicolinc@nvidia.com \
--cc=pasha.tatashin@soleen.com \
--cc=praan@google.com \
--cc=robin.murphy@arm.com \
--cc=skhawaja@google.com \
--cc=smostafa@google.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox