From: Alex Mastro <amastro@fb.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>,
Alejandro Jimenez <alejandro.j.jimenez@oracle.com>,
David Matlack <dmatlack@google.com>, <kvm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 0/3] vfio: handle DMA map/unmap up to the addressable limit
Date: Sat, 25 Oct 2025 11:11:49 -0700 [thread overview]
Message-ID: <aP0S5ZF9l3sWkJ1G@devgpu012.nha5.facebook.com> (raw)
In-Reply-To: <20251012-fix-unmap-v4-0-9eefc90ed14c@fb.com>
Alex and Jason, during my testing, I found that the behavior of range-based
(!VFIO_DMA_UNMAP_FLAG_ALL) VFIO_IOMMU_UNMAP_DMA differs slightly when using
/dev/iommu as the container.
iommufd treats range-based unmap where there are no hits in the range as an
error, and the ioctl fails with ENOENT.
vfio_iommu_type1.c treats this as a success and reports zero bytes unmapped in
vfio_iommu_type1_dma_unmap.size.
It implies to me that we may need some more shimming in
drivers/iommu/iommufd/vfio_compat.c to iron out observable differences in UAPI
usage.
Addressing it would be outside the scope of this patch series, so this mail is
just to make note of my findings.
next prev parent reply other threads:[~2025-10-25 18:12 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-13 5:32 [PATCH v4 0/3] vfio: handle DMA map/unmap up to the addressable limit Alex Mastro
2025-10-13 5:32 ` [PATCH v4 1/3] vfio/type1: sanitize for overflow using check_*_overflow Alex Mastro
2025-10-13 5:32 ` [PATCH v4 2/3] vfio/type1: move iova increment to unmap_unpin_* caller Alex Mastro
2025-10-13 5:32 ` [PATCH v4 3/3] vfio/type1: handle DMA map/unmap up to the addressable limit Alex Mastro
2025-10-21 22:18 ` Alejandro Jimenez
2025-10-22 14:24 ` Alex Mastro
2025-10-15 19:24 ` [PATCH v4 0/3] vfio: " Alex Williamson
2025-10-15 21:25 ` Alejandro Jimenez
2025-10-16 21:19 ` Alex Mastro
2025-10-16 22:01 ` Alex Williamson
2025-10-17 16:29 ` Alex Mastro
2025-10-20 21:36 ` Alex Williamson
2025-10-21 16:25 ` Alex Mastro
2025-10-21 16:31 ` David Matlack
2025-10-21 19:13 ` Alex Mastro
2025-10-22 0:38 ` David Matlack
2025-10-22 14:55 ` Alex Mastro
2025-10-23 20:52 ` Alex Mastro
2025-10-23 22:33 ` Alex Williamson
2025-10-27 16:02 ` Alex Mastro
2025-10-28 1:57 ` Alex Williamson
2025-10-28 15:29 ` Alex Mastro
2025-10-21 12:36 ` Jason Gunthorpe
2025-10-21 22:21 ` Alejandro Jimenez
2025-10-25 18:11 ` Alex Mastro [this message]
2025-10-27 13:39 ` Jason Gunthorpe
2025-10-28 18:42 ` Alex Mastro
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