From nobody Wed Feb 11 11:08:19 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 6A71DC7618D for ; Thu, 6 Apr 2023 14:38:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239262AbjDFOiq (ORCPT ); Thu, 6 Apr 2023 10:38:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229931AbjDFOi2 (ORCPT ); Thu, 6 Apr 2023 10:38:28 -0400 Received: from frasgout12.his.huawei.com (frasgout12.his.huawei.com [14.137.139.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 697B1CA0A for ; Thu, 6 Apr 2023 07:36:29 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.18.147.229]) by frasgout12.his.huawei.com (SkyGuard) with ESMTP id 4PskM76kxqz9xFrM for ; Thu, 6 Apr 2023 22:26:11 +0800 (CST) Received: from A2101119013HW2.china.huawei.com (unknown [10.48.151.63]) by APP2 (Coremail) with SMTP id GxC2BwDnizLG2C5kZfv8AQ--.49S2; Thu, 06 Apr 2023 15:36:00 +0100 (CET) From: Petr Tesarik To: Christoph Hellwig , Marek Szyprowski , Robin Murphy , Petr Tesarik , iommu@lists.linux.dev (open list:DMA MAPPING HELPERS), linux-kernel@vger.kernel.org (open list) Cc: Roberto Sassu , petr@tesarici.cz Subject: [PATCH v1] swiotlb: fix a braino in the alignment check fix Date: Thu, 6 Apr 2023 16:35:39 +0200 Message-Id: <20230406143539.25-1-petrtesarik@huaweicloud.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: GxC2BwDnizLG2C5kZfv8AQ--.49S2 X-Coremail-Antispam: 1UD129KBjvJXoW7KF43CF17Wr43Cw47Jr17Awb_yoW8tF13pF 1xJF4ktFWUtr10qa42k3s8XFy0g34DKw17GrZIg34YgryDJF1DWr9F9ry2gryF9F4fGFy3 uasI9rWjvFy7J3DanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkjb4IE77IF4wAFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Jr0_JF4l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Jr0_Gr1l84ACjcxK6I8E87Iv67AKxVW8JVWxJwA2z4x0Y4vEx4A2jsIEc7CjxV AFwI0_Gr0_Gr1UM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40E x7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x 0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lc7CjxVAKzI0EY4vE52x082I5MxAIw28IcxkI 7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxV Cjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY 6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVWUJVW8JwCI42IY6x AIw20EY4v20xvaj40_WFyUJVCq3wCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv 6xkF7I0E14v26r1j6r4UYxBIdaVFxhVjvjDU0xZFpf9x07je9a9UUUUU= X-CM-SenderInfo: hshw23xhvd2x3n6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Petr Tesarik The alignment mask in swiotlb_do_find_slots() masks off the high bits which are not relevant for the alignment, so multiple requirements are combined with a bitwise OR rather than AND. In plain English, the stricter the alignment, the more bits must be set in iotlb_align_mask. Confusion may arise from the fact that the same variable is also used to mask off the offset within a swiotlb slot, which is achieved with a bitwise AND. Fixes: 0eee5ae10256 ("swiotlb: fix slot alignment checks") Reported-by: Dexuan Cui Link: https://lore.kernel.org/all/CAA42JLa1y9jJ7BgQvXeUYQh-K2mDNHd2BYZ4iZUz= 33r5zY7oAQ@mail.gmail.com/ Reported-by: Kelsey Steele Link: https://lore.kernel.org/all/20230405003549.GA21326@linuxonhyperv3.guj= 3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net/ Signed-off-by: Petr Tesarik Tested-by: Dexuan Cui --- kernel/dma/swiotlb.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 5b919ef832b6..dac42a2ad588 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -623,7 +623,7 @@ static int swiotlb_do_find_slots(struct device *dev, in= t area_index, phys_to_dma_unencrypted(dev, mem->start) & boundary_mask; unsigned long max_slots =3D get_max_slots(boundary_mask); unsigned int iotlb_align_mask =3D - dma_get_min_align_mask(dev) & ~(IO_TLB_SIZE - 1); + dma_get_min_align_mask(dev) | alloc_align_mask; unsigned int nslots =3D nr_slots(alloc_size), stride; unsigned int offset =3D swiotlb_align_offset(dev, orig_addr); unsigned int index, slots_checked, count =3D 0, i; @@ -639,8 +639,8 @@ static int swiotlb_do_find_slots(struct device *dev, in= t area_index, * allocations. */ if (alloc_size >=3D PAGE_SIZE) - iotlb_align_mask &=3D PAGE_MASK; - iotlb_align_mask &=3D alloc_align_mask; + iotlb_align_mask |=3D ~PAGE_MASK; + iotlb_align_mask &=3D ~(IO_TLB_SIZE - 1); =20 /* * For mappings with an alignment requirement don't bother looping to --=20 2.25.1