From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 87B49C3600C for ; Thu, 3 Apr 2025 16:02:05 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1u0N0G-0006Et-2q; Thu, 03 Apr 2025 12:01:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1u0Mzy-00067N-HK; Thu, 03 Apr 2025 12:01:07 -0400 Received: from ssh.movementarian.org ([139.162.205.133] helo=movementarian.org) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1u0Mzw-0001fX-As; Thu, 03 Apr 2025 12:00:57 -0400 Received: from movement by movementarian.org with local (Exim 4.95) (envelope-from ) id 1u0Mzt-005wkW-76; Thu, 03 Apr 2025 17:00:53 +0100 Date: Thu, 3 Apr 2025 17:00:53 +0100 From: John Levon To: =?iso-8859-1?Q?C=E9dric?= Le Goater Cc: qemu-devel@nongnu.org, Jason Herne , Thanos Makatos , Halil Pasic , Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= , Eric Farman , Tony Krowiak , Thomas Huth , qemu-s390x@nongnu.org, Matthew Rosato , Paolo Bonzini , =?iso-8859-1?Q?Marc-Andr=E9?= Lureau , Stefano Garzarella , Alex Williamson , David Hildenbrand , Peter Xu , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , "Michael S. Tsirkin" , Jagannathan Raman , John Johnson , Elena Ufimtseva Subject: Re: [PATCH v8 08/28] vfio: add region cache Message-ID: References: <20250219144858.266455-1-john.levon@nutanix.com> <20250219144858.266455-9-john.levon@nutanix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Url: http://www.movementarian.org/ Received-SPF: pass client-ip=139.162.205.133; envelope-from=movement@movementarian.org; helo=movementarian.org X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Thu, Apr 03, 2025 at 05:46:03PM +0200, Cédric Le Goater wrote: > > +static void vfio_get_all_regions(VFIODevice *vbasedev) > > +{ > > + struct vfio_region_info *info; > > + int i; > > + > > + for (i = 0; i < vbasedev->num_regions; i++) { > > + vfio_get_region_info(vbasedev, i, &info); > > + } > > +} > > + > > void vfio_prepare_device(VFIODevice *vbasedev, VFIOContainerBase *bcontainer, > > VFIOGroup *group, struct vfio_device_info *info) > > { > > @@ -1586,6 +1596,8 @@ void vfio_prepare_device(VFIODevice *vbasedev, VFIOContainerBase *bcontainer, > > } > > QLIST_INSERT_HEAD(&vfio_device_list, vbasedev, global_next); > > + > > + vfio_get_all_regions(vbasedev); > > } > > + /* check cache */ > > + if (vbasedev->regions[index] != NULL) { > > + *info = vbasedev->regions[index]; > > + return 0; > > + } > > + > > why not populate vbasedev->regions[index] in vfio_get_all_regions() ? Good question. I presume it's not possible for us to ever look up a region that has somehow appeared *after* vfio_prepare_device() ? We'd end up off the end of the array in that case anyway. regards john