From nobody Fri Feb 13 15:42:38 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 EECA8E6FE32 for ; Fri, 22 Sep 2023 13:48:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234194AbjIVNsO (ORCPT ); Fri, 22 Sep 2023 09:48:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52528 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234147AbjIVNsM (ORCPT ); Fri, 22 Sep 2023 09:48:12 -0400 X-Greylist: delayed 447 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Fri, 22 Sep 2023 06:48:05 PDT Received: from mail.marcansoft.com (marcansoft.com [212.63.210.85]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C4FCD92; Fri, 22 Sep 2023 06:48:05 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: sendonly@marcansoft.com) by mail.marcansoft.com (Postfix) with ESMTPSA id E9BE24203C; Fri, 22 Sep 2023 13:40:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=marcan.st; s=default; t=1695390035; bh=wnRMaJBOS2DBNUxEtrGxJj6grzGED1qsQnxvwl3853Q=; h=From:Date:Subject:To:Cc; b=EL+kQP6z2D1r/FcD1TXdu49qUlyYgYgj0amx/V7WZ9ABEa/REXdo+1rVGrP5gIKpu geBzkpMjccNNO5cAGwX2nbtGyBjoKy0G5FwgpoB5xobEZXQdtOe4vKBrZLUavK08HW cxRQAeVZdV2m+EYqL0bjS3NA7Gx6HxP6jFJuxVMLBGyCsm8TtvhygKKpF+bi49b166 4uC99oKwrAvYnU20loGtw829HDNtfL3B/s8vNfiSEgQLcGJsg+7mTo/gTrDZpa+Gaq y4U7QZohJ04few8TmHtIC1vkcmc1HvG3dD6Hs2nOw42BMUobiKs9v5wkoPn7dhvDlS gG8UbmaElcWNw== From: Hector Martin Date: Fri, 22 Sep 2023 22:40:20 +0900 Subject: [PATCH REGRESSION] iommu: Only allocate FQ domains for IOMMUs that support them MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20230922-iommu-type-regression-v1-1-1ed3825b2c38@marcan.st> X-B4-Tracking: v=1; b=H4sIAEOZDWUC/x3Myw5AQAxA0V+RrjUZRYRfEQuPDl14pIOQiX83L O/iXA+OVdhBFXlQPsXJuoRI4gj6qV1GRhlCAxlKTUmEss7zgfu9MSqPyu4TSHmX2SwdbFEYCHZ TtnL937p5nhd8EatbZwAAAA== To: Joerg Roedel , Will Deacon , Robin Murphy , Jason Gunthorpe , Jerry Snitselaar Cc: Joerg Roedel , Neal Gompa , "Justin M. Forbes" , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, asahi@lists.linux.dev, stable@vger.kernel.org, regressions@lists.linux.dev, Hector Martin X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=1654; i=marcan@marcan.st; h=from:subject:message-id; bh=wnRMaJBOS2DBNUxEtrGxJj6grzGED1qsQnxvwl3853Q=; b=owGbwMvMwCUm+yP4NEe/cRLjabUkhlTemf6MGpdr17EecAmcefbUi4gtXz2fGH8+UWdeZCSzT uqnx3arjlIWBjEuBlkxRZbGE72nuj2nn1NXTZkOM4eVCWQIAxenAEyk4gvDT8bEBMkPJ67IfVtn yV+s31PwoTNX+83atU/P8m3g375coYeRoX/Oi7b2+oKDy0Sr3eZP3Hw85t/sV/OsFJfeuW7EPyn HgRkA X-Developer-Key: i=marcan@marcan.st; a=openpgp; fpr=FC18F00317968B7BE86201CBE22A629A4C515DD5 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit a4fdd9762272 ("iommu: Use flush queue capability") hid the IOMMU_DOMAIN_DMA_FQ domain type from domain allocation. A check was introduced in iommu_dma_init_domain() to fall back if not supported, but this check runs too late: by that point, devices have been attached to the IOMMU, and the IOMMU driver might not expect FQ domains at ops->attach_dev() time. Ensure that we immediately clamp FQ domains to plain DMA if not supported by the driver at device attach time, not later. This regressed apple-dart in v6.5. Cc: regressions@lists.linux.dev Cc: stable@vger.kernel.org Fixes: a4fdd9762272 ("iommu: Use flush queue capability") Signed-off-by: Hector Martin --- drivers/iommu/iommu.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 3bfc56df4f78..12464eaa8d91 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2039,6 +2039,15 @@ static int __iommu_attach_device(struct iommu_domain= *domain, if (unlikely(domain->ops->attach_dev =3D=3D NULL)) return -ENODEV; =20 + /* + * Ensure we do not try to attach devices to FQ domains if the + * IOMMU does not support them. We can safely fall back to + * non-FQ. + */ + if (domain->type =3D=3D IOMMU_DOMAIN_DMA_FQ && + !device_iommu_capable(dev, IOMMU_CAP_DEFERRED_FLUSH)) + domain->type =3D IOMMU_DOMAIN_DMA; + ret =3D domain->ops->attach_dev(domain, dev); if (ret) return ret; --- base-commit: ce9ecca0238b140b88f43859b211c9fdfd8e5b70 change-id: 20230922-iommu-type-regression-25b4f43df770 Best regards, --=20 Hector Martin