From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BAD622E7BD3; Sun, 18 Jan 2026 14:29:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768746553; cv=none; b=nZ+X5zfXeu5sTxvycjoNCyG5MVhDXiZzY8XU9y4p70XL/Ieu6Mr9wQR6RZHH3fqVWS4DGVE5cMla6/zZkl8MpMEuCdlS6RAGaSa/ckAfn8kNhi0azbd6zbXTRnHp2DZIt2WYEWlCZUQ2TThTp7J7i7sS80nlqTWbS4YVMTESPSs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768746553; c=relaxed/simple; bh=0+eaeMN1EHDT+lkQ4GIUQ4W12gE3E7ctCy4zVXTxlPk=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=PGv9pMT110CbUZUs1Rtp1ljQm8pwlWIBITgzaB7p9Tb/tjc44HdNCZRnC7PaW7qmqlnklwUsx4yVH6by6GKzAqD2mWu73tBD+/01iq4nApx0adawiHqUjHFy13ILHYTG3B2eoFiP0NJ2rX3wrzTSsHU+K6vvF6OwRBaHtCdmrkw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=hP6EF4ql; arc=none smtp.client-ip=198.175.65.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="hP6EF4ql" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1768746552; x=1800282552; h=message-id:subject:from:to:cc:date:in-reply-to: references:content-transfer-encoding:mime-version; bh=0+eaeMN1EHDT+lkQ4GIUQ4W12gE3E7ctCy4zVXTxlPk=; b=hP6EF4qlFgUINJkL2wEWjnpQchlqDrmCV5hr8bn0J7Uo+tKFnsaVtLe5 js9HqIZiQAm6dGmfPqM1uEZ0/rtrljDFMYUHZi2VRnXNk+HOM11u7qe5t 2lxaYRRbnw1VNY6qoJ0KTMO38YSxMVt9mGtQatwQwPmu64kdxPLVG1cnv nHs2WHeRfDrgNGNJNhphBhglK+hwquVfgPkGRjoVCnsDFlYaE3kagKKQv dEJXnzoTBc0V0gfhzHKXhS85NNHAGPA+1QVjEoxU21WjztschKfCzyPao UdxJbF89U36/gogfK8j1f3Wr4Cf3dr9TctJREiXANulNL2cYXMOtl/jNb Q==; X-CSE-ConnectionGUID: qgHvUmPyRUOtNoTV95qS4g== X-CSE-MsgGUID: tzlyhUPOSTWhEG1SFRRBKA== X-IronPort-AV: E=McAfee;i="6800,10657,11675"; a="70146415" X-IronPort-AV: E=Sophos;i="6.21,235,1763452800"; d="scan'208";a="70146415" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by orvoesa108.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jan 2026 06:29:12 -0800 X-CSE-ConnectionGUID: nCY8yfQeS1CtWSbdd073Iw== X-CSE-MsgGUID: VxUvo3fYR72cV06gEahrOg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,235,1763452800"; d="scan'208";a="205447268" Received: from egrumbac-mobl6.ger.corp.intel.com (HELO [10.245.244.5]) ([10.245.244.5]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jan 2026 06:29:04 -0800 Message-ID: <8bc75706c18c410f9564805c487907aba0aab627.camel@linux.intel.com> Subject: Re: [PATCH v2 2/4] dma-buf: Document revoke semantics From: Thomas =?ISO-8859-1?Q?Hellstr=F6m?= To: Leon Romanovsky , Sumit Semwal , Christian =?ISO-8859-1?Q?K=F6nig?= , Alex Deucher , David Airlie , Simona Vetter , Gerd Hoffmann , Dmitry Osipenko , Gurchetan Singh , Chia-I Wu , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Lucas De Marchi , Rodrigo Vivi , Jason Gunthorpe , Kevin Tian , Joerg Roedel , Will Deacon , Robin Murphy , Alex Williamson Cc: 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 Date: Sun, 18 Jan 2026 15:29:02 +0100 In-Reply-To: <20260118-dmabuf-revoke-v2-2-a03bb27c0875@nvidia.com> References: <20260118-dmabuf-revoke-v2-0-a03bb27c0875@nvidia.com> <20260118-dmabuf-revoke-v2-2-a03bb27c0875@nvidia.com> Organization: Intel Sweden AB, Registration Number: 556189-6027 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.54.3 (3.54.3-2.fc41) Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Sun, 2026-01-18 at 14:08 +0200, Leon Romanovsky wrote: > From: Leon Romanovsky >=20 > Document a DMA-buf revoke mechanism that allows an exporter to > explicitly > invalidate ("kill") a shared buffer after it has been handed out to > importers. Once revoked, all further CPU and device access is > blocked, and > importers consistently observe failure. See previous comment WRT this. >=20 > This requires both importers and exporters to honor the revoke > contract. >=20 > For importers, this means implementing .invalidate_mappings() and > calling > dma_buf_pin() after the DMA=E2=80=91buf is attached to verify the exporte= r=E2=80=99s > support > for revocation. Why would the importer want to verify the exporter's support for revocation? If the exporter doesn't support it, the only consequence would be that invalidate_mappings() would never be called, and that dma_buf_pin() is a NOP. Besides, dma_buf_pin() would not return an error if the exporter doesn't implement the pin() callback? Or perhaps I missed a prereq patch? Thanks, Thomas