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charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: BN9PR11MB5276.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 5cc31ce0-4357-488e-e8f4-08daab151d86 X-MS-Exchange-CrossTenant-originalarrivaltime: 10 Oct 2022 23:14:00.4233 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: eSi9dbkbQ/kByleLt33Ox9eN53hTB4Gl8bwWOuRYDhTLbDXQgMlAqVMd6LXI/AAQF27U7V2UQm1Qcv6l75ajTA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY8PR11MB7241 X-OriginatorOrg: intel.com X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tvrtko Ursulin , Jason Gunthorpe , David Airlie , "intel-gfx@lists.freedesktop.org" , "dri-devel@lists.freedesktop.org" , "Vivi, Rodrigo" , "stable@vger.kernel.org" , "intel-gvt-dev@lists.freedesktop.org" , Christoph Hellwig Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" > From: Alex Williamson > Sent: Friday, October 7, 2022 2:31 AM >=20 > On Thu, 6 Oct 2022 08:37:09 -0300 > Jason Gunthorpe wrote: >=20 > > On Wed, Oct 05, 2022 at 04:03:56PM -0600, Alex Williamson wrote: > > > We can't have a .remove callback that does nothing, this breaks > > > removing the device while it's in use. Once we have the > > > vfio_unregister_group_dev() fix below, we'll block until the device i= s > > > unused, at which point vgpu->attached becomes false. Unless I'm > > > missing something, I think we should also follow-up with a patch to > > > remove that bogus warn-on branch, right? Thanks, > > > > Yes, looks right to me. > > > > I question all the logical arround attached, where is the locking? >=20 > Zhenyu, Zhi, Kevin, >=20 > Could someone please take a look at use of vgpu->attached in the GVT-g > driver? It's use in intel_vgpu_remove() is bogus, the .release > callback needs to use vfio_unregister_group_dev() to wait for the > device to be unused. The WARN_ON/return here breaks all future use of > the device. I assume @attached has something to do with the page table > interface with KVM, but it all looks racy anyway. >=20 > Also, whatever purpose vgpu->released served looks unnecessary now. > Thanks, >=20 Zhi is looking at it.