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From: Jason Gunthorpe <jgg@nvidia.com>
To: Steven Sistare <steven.sistare@oracle.com>
Cc: Alex Williamson <alex.williamson@redhat.com>, iommu@lists.linux.dev
Subject: Re: mapping files for iommufd
Date: Tue, 13 Aug 2024 11:36:20 -0300	[thread overview]
Message-ID: <20240813143620.GW8378@nvidia.com> (raw)
In-Reply-To: <b48cba98-cf51-40dc-9f57-4c1a7c493f78@oracle.com>

On Tue, Aug 13, 2024 at 10:23:10AM -0400, Steven Sistare wrote:

> The correct explanation is my test succeeded for an older kernel, based on 5.15.
> It failed in 6.9.  This change in 6.4 (which Jason quotes from above) appears to be
> the reason:
>   8ac2684 mm/gup: disallow FOLL_LONGTERM GUP-nonfast writing to file-backed mappings
> 
> I do not question the need for that fix, but I am surprised that QEMU users have not
> complained about new kernels failing for hugetlbfs plus vfio.  Maybe most are still
> on older stable kernels (as I was).

hugetlbfs is supposed to work

Normal filesystems are not

Jason

  reply	other threads:[~2024-08-13 14:36 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-12 18:09 mapping files for iommufd Steven Sistare
2024-08-12 18:40 ` Jason Gunthorpe
2024-08-12 18:56   ` Steven Sistare
2024-08-12 21:05     ` Alex Williamson
2024-08-13 14:23       ` Steven Sistare
2024-08-13 14:36         ` Jason Gunthorpe [this message]
2024-08-13 15:13           ` Steven Sistare

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