From nobody Fri Jan 2 13:37:33 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6055ACDB473 for ; Wed, 11 Oct 2023 18:15:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235017AbjJKSPR (ORCPT ); Wed, 11 Oct 2023 14:15:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233342AbjJKSPI (ORCPT ); Wed, 11 Oct 2023 14:15:08 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C69BC9E for ; Wed, 11 Oct 2023 11:15:06 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 545E8150C; Wed, 11 Oct 2023 11:15:47 -0700 (PDT) Received: from e121345-lin.cambridge.arm.com (e121345-lin.cambridge.arm.com [10.1.196.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id B5E143F5A1; Wed, 11 Oct 2023 11:15:05 -0700 (PDT) From: Robin Murphy To: joro@8bytes.org, will@kernel.org Cc: iommu@lists.linux.dev, jgg@nvidia.com, baolu.lu@linux.intel.com, linux-kernel@vger.kernel.org Subject: [PATCH v5 4/7] iommu: Decouple iommu_domain_alloc() from bus ops Date: Wed, 11 Oct 2023 19:14:51 +0100 Message-Id: <81a0a66d76b3826f1a0b55d7fbaf0986034c7abc.1697047261.git.robin.murphy@arm.com> X-Mailer: git-send-email 2.39.2.101.g768bb238c484.dirty In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" As the final remaining piece of bus-dependent API, iommu_domain_alloc() can now take responsibility for the "one iommu_ops per bus" rule for itself. It turns out we can't safely make the internal allocation call any more group-based or device-based yet - that will have to wait until the external callers can pass the right thing - but we can at least get as far as deriving "bus ops" based on which driver is actually managing devices on the given bus, rather than whichever driver won the race to register first. This will then leave us able to convert the last of the core internals over to the IOMMU-instance model, allow multiple drivers to register and actually coexist (modulo the above limitation for unmanaged domain users in the short term), and start trying to solve the long-standing iommu_probe_device() mess. Signed-off-by: Robin Murphy Reviewed-by: Jason Gunthorpe Reviewed-by: Jerry Snitselaar --- v5: Rewrite, de-scoping to just retrieve ops under the same assumptions as the existing code. --- drivers/iommu/iommu.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 578292d3b152..18667dc2ff86 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2140,12 +2140,31 @@ __iommu_group_domain_alloc(struct iommu_group *grou= p, unsigned int type) return __iommu_domain_alloc(dev_iommu_ops(dev), dev, type); } =20 +static int __iommu_domain_alloc_dev(struct device *dev, void *data) +{ + const struct iommu_ops **ops =3D data; + + if (!dev_has_iommu(dev)) + return 0; + + if (WARN_ONCE(*ops && *ops !=3D dev_iommu_ops(dev), + "Multiple IOMMU drivers present for bus %s, which the public IOMMU= API can't fully support yet. You will still need to disable one or more fo= r this to work, sorry!\n", + dev_bus_name(dev))) + return -EBUSY; + + *ops =3D dev_iommu_ops(dev); + return 0; +} + struct iommu_domain *iommu_domain_alloc(const struct bus_type *bus) { - if (bus =3D=3D NULL || bus->iommu_ops =3D=3D NULL) + const struct iommu_ops *ops =3D NULL; + int err =3D bus_for_each_dev(bus, NULL, &ops, __iommu_domain_alloc_dev); + + if (err || !ops) return NULL; - return __iommu_domain_alloc(bus->iommu_ops, NULL, - IOMMU_DOMAIN_UNMANAGED); + + return __iommu_domain_alloc(ops, NULL, IOMMU_DOMAIN_UNMANAGED); } EXPORT_SYMBOL_GPL(iommu_domain_alloc); =20 --=20 2.39.2.101.g768bb238c484.dirty