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Tue, 20 Jul 2021 07:05:37 +0000 From: Long Li To: Christoph Hellwig , Bart Van Assche CC: "longli@linuxonhyperv.com" , "linux-fs@vger.kernel.org" , "linux-block@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-hyperv@vger.kernel.org" , "gregkh@linuxfoundation.org" Subject: RE: [Patch v4 0/3] Introduce a driver to support host accelerated access to Microsoft Azure Blob Thread-Topic: [Patch v4 0/3] Introduce a driver to support host accelerated access to Microsoft Azure Blob Thread-Index: AQHXfRe50VdmS4suz0yD44Lpyf2vv6tLR9UAgAAXUgCAAA60sA== Date: Tue, 20 Jul 2021 07:05:37 +0000 Message-ID: References: <1626751866-15765-1-git-send-email-longli@linuxonhyperv.com> <82e8bec6-4f6f-08d7-90db-9661f675749d@acm.org> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: msip_labels: MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_ActionId=5371eef0-9524-4265-8efd-e30216c7dfb2;MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_ContentBits=0;MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Enabled=true;MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Method=Standard;MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Name=Internal;MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_SetDate=2021-07-20T06:54:01Z;MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_SiteId=72f988bf-86f1-41af-91ab-2d7cd011db47; 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charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: DM6PR21MB1513.namprd21.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 8dc774b8-523f-42cc-6ae0-08d94b4cc6b7 X-MS-Exchange-CrossTenant-originalarrivaltime: 20 Jul 2021 07:05:37.2186 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: YWLvwDHheD0nY7XpbEmLbI/l5VwUDWOF7YQXfjpjLcavBHJX3UBrcIIA/9BAZADCLLIhj7+SFF/QZvX8oudSWw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR2101MB0901 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org > Subject: Re: [Patch v4 0/3] Introduce a driver to support host accelerate= d > access to Microsoft Azure Blob >=20 > On Mon, Jul 19, 2021 at 09:37:56PM -0700, Bart Van Assche wrote: > > such that this object storage driver can be implemented as a > > user-space library instead of as a kernel driver? As you may know vfio > > users can either use eventfds for completion notifications or polling. > > An interface like io_uring can be built easily on top of vfio. >=20 > Yes. Similar to say the NVMe K/V command set this does not look like a > candidate for a kernel driver. The driver is modeled to support multiple processes/users over a VMBUS channel. I don't see a way that this can be implemented through VFIO?=20 Even if it can be done, this exposes a security risk as the same VMBUS channel is shared by multiple processes in user-mode.