From nobody Fri Jan 2 05:00:14 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 C58C3CDB465 for ; Mon, 16 Oct 2023 12:53:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233563AbjJPMxQ (ORCPT ); Mon, 16 Oct 2023 08:53:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233491AbjJPMxO (ORCPT ); Mon, 16 Oct 2023 08:53:14 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 01408A2 for ; Mon, 16 Oct 2023 05:53:11 -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 476632F4; Mon, 16 Oct 2023 05:53:52 -0700 (PDT) Received: from entos-ampere02.shanghai.arm.com (unknown [10.169.212.212]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5040C3F5A1; Mon, 16 Oct 2023 05:53:09 -0700 (PDT) From: Jia He To: Christoph Hellwig , Marek Szyprowski , Robin Murphy , iommu@lists.linux.dev Cc: linux-kernel@vger.kernel.org, nd@arm.com, Jia He Subject: [PATCH v3 2/2] dma-mapping: fix dma_addressing_limited() if dma_range_map can't cover all system RAM Date: Mon, 16 Oct 2023 12:52:54 +0000 Message-Id: <20231016125254.1875-3-justin.he@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20231016125254.1875-1-justin.he@arm.com> References: <20231016125254.1875-1-justin.he@arm.com> 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" There is an unusual case that the range map covers right up to the top of system RAM, but leaves a hole somewhere lower down. Then it prevents the nvme device dma mapping in the checking path of phys_to_dma() and causes the hangs at boot. E.g. On an Armv8 Ampere server, the dsdt ACPI table is: Method (_DMA, 0, Serialized) // _DMA: Direct Memory Access { Name (RBUF, ResourceTemplate () { QWordMemory (ResourceConsumer, PosDecode, MinFixed, MaxFixed, Cacheable, ReadWrite, 0x0000000000000000, // Granularity 0x0000000000000000, // Range Minimum 0x00000000FFFFFFFF, // Range Maximum 0x0000000000000000, // Translation Offset 0x0000000100000000, // Length ,, , AddressRangeMemory, TypeStatic) QWordMemory (ResourceConsumer, PosDecode, MinFixed, MaxFixed, Cacheable, ReadWrite, 0x0000000000000000, // Granularity 0x0000006010200000, // Range Minimum 0x000000602FFFFFFF, // Range Maximum 0x0000000000000000, // Translation Offset 0x000000001FE00000, // Length ,, , AddressRangeMemory, TypeStatic) QWordMemory (ResourceConsumer, PosDecode, MinFixed, MaxFixed, Cacheable, ReadWrite, 0x0000000000000000, // Granularity 0x00000060F0000000, // Range Minimum 0x00000060FFFFFFFF, // Range Maximum 0x0000000000000000, // Translation Offset 0x0000000010000000, // Length ,, , AddressRangeMemory, TypeStatic) QWordMemory (ResourceConsumer, PosDecode, MinFixed, MaxFixed, Cacheable, ReadWrite, 0x0000000000000000, // Granularity 0x0000007000000000, // Range Minimum 0x000003FFFFFFFFFF, // Range Maximum 0x0000000000000000, // Translation Offset 0x0000039000000000, // Length ,, , AddressRangeMemory, TypeStatic) }) But the System RAM ranges are: cat /proc/iomem |grep -i ram 90000000-91ffffff : System RAM 92900000-fffbffff : System RAM 880000000-fffffffff : System RAM 8800000000-bff5990fff : System RAM bff59d0000-bff5a4ffff : System RAM bff8000000-bfffffffff : System RAM So some RAM ranges are out of dma_range_map. Fix it by checking whether each of the system RAM resources can be properly encompassed within the dma_range_map. Signed-off-by: Jia He --- kernel/dma/mapping.c | 49 ++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 47 insertions(+), 2 deletions(-) diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 5bfe782f9a7f..9889d1d25a7f 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -7,6 +7,7 @@ */ #include /* for max_pfn */ #include +#include /* for bus_dma_region */ #include #include #include @@ -793,6 +794,47 @@ int dma_set_coherent_mask(struct device *dev, u64 mask) } EXPORT_SYMBOL(dma_set_coherent_mask); =20 +/* + * To check whether all ram resource ranges are covered by dma range map + * Returns 0 when continuous check is needed + * Returns 1 if there is some RAM range can't be covered by dma_range_map + */ +static int check_ram_in_range_map(unsigned long start_pfn, + unsigned long nr_pages, void *data) +{ + unsigned long end_pfn =3D start_pfn + nr_pages; + struct device *dev =3D (struct device *)data; + struct bus_dma_region *bdr =3D NULL; + const struct bus_dma_region *m; + + while (start_pfn < end_pfn) { + for (m =3D dev->dma_range_map; PFN_DOWN(m->size); m++) { + unsigned long cpu_start_pfn =3D PFN_DOWN(m->cpu_start); + + if (start_pfn >=3D cpu_start_pfn + && start_pfn - cpu_start_pfn < PFN_DOWN(m->size)) { + bdr =3D (struct bus_dma_region *)m; + break; + } + } + if (!bdr) + return 1; + + start_pfn =3D PFN_DOWN(bdr->cpu_start) + PFN_DOWN(bdr->size); + } + + return 0; +} + +static bool all_ram_in_dma_range_map(struct device *dev) +{ + if (!dev->dma_range_map) + return 1; + + return !walk_system_ram_range(0, PFN_DOWN(ULONG_MAX) + 1, dev, + check_ram_in_range_map); +} + /** * dma_addressing_limited - return if the device is addressing limited * @dev: device to check @@ -803,8 +845,11 @@ EXPORT_SYMBOL(dma_set_coherent_mask); */ bool dma_addressing_limited(struct device *dev) { - return min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) < - dma_get_required_mask(dev); + if (min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) < + dma_get_required_mask(dev)) + return true; + + return !all_ram_in_dma_range_map(dev); } EXPORT_SYMBOL(dma_addressing_limited); =20 --=20 2.25.1