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[142.162.112.119]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8942e6ad75asm86947906d6.31.2026.01.19.11.54.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Jan 2026 11:54:44 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1vhvKm-00000005JRT-0mKA; Mon, 19 Jan 2026 15:54:44 -0400 Date: Mon, 19 Jan 2026 15:54:44 -0400 From: Jason Gunthorpe To: Leon Romanovsky Cc: Sumit Semwal , Christian =?utf-8?B?S8O2bmln?= , Alex Deucher , David Airlie , Simona Vetter , Gerd Hoffmann , Dmitry Osipenko , Gurchetan Singh , Chia-I Wu , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Lucas De Marchi , Thomas =?utf-8?Q?Hellstr=C3=B6m?= , Rodrigo Vivi , Kevin Tian , Joerg Roedel , Will Deacon , Robin Murphy , Alex Williamson , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, virtualization@lists.linux.dev, intel-xe@lists.freedesktop.org, linux-rdma@vger.kernel.org, iommu@lists.linux.dev, kvm@vger.kernel.org Subject: Re: [PATCH v2 3/4] iommufd: Require DMABUF revoke semantics Message-ID: <20260119195444.GL961572@ziepe.ca> References: <20260118-dmabuf-revoke-v2-0-a03bb27c0875@nvidia.com> <20260118-dmabuf-revoke-v2-3-a03bb27c0875@nvidia.com> <20260119165951.GI961572@ziepe.ca> <20260119182300.GO13201@unreal> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260119182300.GO13201@unreal> On Mon, Jan 19, 2026 at 08:23:00PM +0200, Leon Romanovsky wrote: > On Mon, Jan 19, 2026 at 12:59:51PM -0400, Jason Gunthorpe wrote: > > On Sun, Jan 18, 2026 at 02:08:47PM +0200, Leon Romanovsky wrote: > > > From: Leon Romanovsky > > > > > > IOMMUFD does not support page fault handling, and after a call to > > > .invalidate_mappings() all mappings become invalid. Ensure that > > > the IOMMUFD DMABUF importer is bound to a revoke‑aware DMABUF exporter > > > (for example, VFIO). > > > > > > Signed-off-by: Leon Romanovsky > > > --- > > > drivers/iommu/iommufd/pages.c | 9 ++++++++- > > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/iommu/iommufd/pages.c b/drivers/iommu/iommufd/pages.c > > > index 76f900fa1687..a5eb2bc4ef48 100644 > > > --- a/drivers/iommu/iommufd/pages.c > > > +++ b/drivers/iommu/iommufd/pages.c > > > @@ -1501,16 +1501,22 @@ static int iopt_map_dmabuf(struct iommufd_ctx *ictx, struct iopt_pages *pages, > > > mutex_unlock(&pages->mutex); > > > } > > > > > > - rc = sym_vfio_pci_dma_buf_iommufd_map(attach, &pages->dmabuf.phys); > > > + rc = dma_buf_pin(attach); > > > if (rc) > > > goto err_detach; > > > > > > + rc = sym_vfio_pci_dma_buf_iommufd_map(attach, &pages->dmabuf.phys); > > > + if (rc) > > > + goto err_unpin; > > > + > > > dma_resv_unlock(dmabuf->resv); > > > > > > /* On success iopt_release_pages() will detach and put the dmabuf. */ > > > pages->dmabuf.attach = attach; > > > return 0; > > > > Don't we need an explicit unpin after unmapping? > > Yes, but this patch is going to be dropped in v3 because of this > suggestion. > https://lore.kernel.org/all/a397ff1e-615f-4873-98a9-940f9c16f85c@amd.com That's not right, that suggestion is about changing VFIO. iommufd must still act as a pinning importer! Jason