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[142.162.112.119]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8c6a71ab288sm1307247385a.6.2026.01.21.05.47.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Jan 2026 05:47:12 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1viYYC-00000006Dum-1GTZ; Wed, 21 Jan 2026 09:47:12 -0400 Date: Wed, 21 Jan 2026 09:47:12 -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 , Felix Kuehling , Alex Williamson , Ankit Agrawal , Vivek Kasireddy , 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 v4 8/8] vfio: Validate dma-buf revocation semantics Message-ID: <20260121134712.GZ961572@ziepe.ca> References: <20260121-dmabuf-revoke-v4-0-d311cbc8633d@nvidia.com> <20260121-dmabuf-revoke-v4-8-d311cbc8633d@nvidia.com> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260121-dmabuf-revoke-v4-8-d311cbc8633d@nvidia.com> On Wed, Jan 21, 2026 at 02:59:16PM +0200, Leon Romanovsky wrote: > From: Leon Romanovsky > > Use the new dma_buf_attach_revocable() helper to restrict attachments to > importers that support mapping invalidation. > > Signed-off-by: Leon Romanovsky > --- > drivers/vfio/pci/vfio_pci_dmabuf.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci_dmabuf.c > index 5fceefc40e27..85056a5a3faf 100644 > --- a/drivers/vfio/pci/vfio_pci_dmabuf.c > +++ b/drivers/vfio/pci/vfio_pci_dmabuf.c > @@ -31,6 +31,9 @@ static int vfio_pci_dma_buf_attach(struct dma_buf *dmabuf, > if (priv->revoked) > return -ENODEV; > > + if (!dma_buf_attach_revocable(attachment)) > + return -EOPNOTSUPP; > + > return 0; > } We need to push an urgent -rc fix to implement a pin function here that always fails. That was missed and it means things like rdma can import vfio when the intention was to block that. It would be bad for that uAPI mistake to reach a released kernel. It's tricky that NULL pin ops means "I support pin" :| Jason