From nobody Sun Sep 14 22:49:45 2025 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 B4BCDC54EE9 for ; Tue, 13 Sep 2022 17:52:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233121AbiIMRwH (ORCPT ); Tue, 13 Sep 2022 13:52:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56310 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230208AbiIMRvk (ORCPT ); Tue, 13 Sep 2022 13:51:40 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3CA389CC2; Tue, 13 Sep 2022 09:50:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D5DEAB80EFC; Tue, 13 Sep 2022 14:21:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3AC90C433B5; Tue, 13 Sep 2022 14:21:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1663078878; bh=AKyBCjV9hs/yvvLPFK6IzsfqGsSmMNIgLy3DPd3o5ms=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bk1deY/ZepgzvmqwvQciHUBSR2joH0SVU2qm7EiimtK0fLMEDtmBIgsDfHsaK8t8M KWWB6d4Gav38EaqQJ5cHKR3tYO/7v+2UTUO44p6ZEDA3BulESn0slYCi3ivsTXfc+X lYUp3GANSkOjOxsIARJuLonPPiE7NGzDtZB2pK9o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lu Baolu , Joerg Roedel Subject: [PATCH 5.15 117/121] iommu/vt-d: Correctly calculate sagaw value of IOMMU Date: Tue, 13 Sep 2022 16:05:08 +0200 Message-Id: <20220913140402.394224802@linuxfoundation.org> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220913140357.323297659@linuxfoundation.org> References: <20220913140357.323297659@linuxfoundation.org> User-Agent: quilt/0.67 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" From: Lu Baolu commit 53fc7ad6edf210b497230ce74b61b322a202470c upstream. The Intel IOMMU driver possibly selects between the first-level and the second-level translation tables for DMA address translation. However, the levels of page-table walks for the 4KB base page size are calculated from the SAGAW field of the capability register, which is only valid for the second-level page table. This causes the IOMMU driver to stop working if the hardware (or the emulated IOMMU) advertises only first-level translation capability and reports the SAGAW field as 0. This solves the above problem by considering both the first level and the second level when calculating the supported page table levels. Fixes: b802d070a52a1 ("iommu/vt-d: Use iova over first level") Cc: stable@vger.kernel.org Signed-off-by: Lu Baolu Link: https://lore.kernel.org/r/20220817023558.3253263-1-baolu.lu@linux.int= el.com Signed-off-by: Joerg Roedel Signed-off-by: Greg Kroah-Hartman --- drivers/iommu/intel/iommu.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -542,14 +542,36 @@ static inline int domain_pfn_supported(s return !(addr_width < BITS_PER_LONG && pfn >> addr_width); } =20 +/* + * Calculate the Supported Adjusted Guest Address Widths of an IOMMU. + * Refer to 11.4.2 of the VT-d spec for the encoding of each bit of + * the returned SAGAW. + */ +static unsigned long __iommu_calculate_sagaw(struct intel_iommu *iommu) +{ + unsigned long fl_sagaw, sl_sagaw; + + fl_sagaw =3D BIT(2) | (cap_fl1gp_support(iommu->cap) ? BIT(3) : 0); + sl_sagaw =3D cap_sagaw(iommu->cap); + + /* Second level only. */ + if (!sm_supported(iommu) || !ecap_flts(iommu->ecap)) + return sl_sagaw; + + /* First level only. */ + if (!ecap_slts(iommu->ecap)) + return fl_sagaw; + + return fl_sagaw & sl_sagaw; +} + static int __iommu_calculate_agaw(struct intel_iommu *iommu, int max_gaw) { unsigned long sagaw; int agaw; =20 - sagaw =3D cap_sagaw(iommu->cap); - for (agaw =3D width_to_agaw(max_gaw); - agaw >=3D 0; agaw--) { + sagaw =3D __iommu_calculate_sagaw(iommu); + for (agaw =3D width_to_agaw(max_gaw); agaw >=3D 0; agaw--) { if (test_bit(agaw, &sagaw)) break; }