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[147.75.80.249]) by mx.google.com with ESMTPS id q16-20020a1709066b1000b00a432149ff40si1733951ejr.108.2024.02.28.05.41.18 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Feb 2024 05:41:18 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-85113-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=kmB8OHgS; arc=pass (i=1 dkim=pass dkdomain=kernel.org); spf=pass (google.com: domain of linux-kernel+bounces-85113-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) smtp.mailfrom="linux-kernel+bounces-85113-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id 0CC181F28BAF for ; Wed, 28 Feb 2024 13:41:18 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 78A88158D69; Wed, 28 Feb 2024 13:39:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kmB8OHgS" Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A0A3E157E8E; Wed, 28 Feb 2024 13:39:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709127587; cv=none; b=ndBGOhCuLHxmQh5HLPBhUCqqDsr7mUCBptVA4dJOfdobcxdf7MzksqTJ1S2n7bZI2MMqnARIGww+QLT+XMvqqzWnD407yMhGmAmRQbcj/TDBeKHoCFyjy4V5fxmy4amLfb7IAYyecuKSH33fGAs9i5tI7uNugxxrz8xbQZLN+GM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709127587; c=relaxed/simple; bh=dxwWmvXzdSSRNkdcGEkNTrMB/45mYo1YIJ2aRH5yEZo=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=A+ovFCLKM92PZeiebaVgYiNVlPnss2iIoAwjK3wRHxkWqf/Qwd+cU9+HRRdhjfscUDi1/vTQZHb8uLRyhjNnYnmJKtlYRudWm+oxhBB4vElbtL8akqHUBxXG1tzmgOwWWMoVqG+lfO02C9APMKbUAsFpq27WNrqnAmTWAHVV2JA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kmB8OHgS; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0115DC433B1; Wed, 28 Feb 2024 13:39:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1709127587; bh=dxwWmvXzdSSRNkdcGEkNTrMB/45mYo1YIJ2aRH5yEZo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kmB8OHgSZHzFyoRS0a5E0qlqyW60IZS83omqXJKgkbElBp3VnU4QXVUd96IDeHblS cQnTR0bae0YQ/gc6istY2EiMzL6JL1E4rDDzEerKy9Cu6Z5p7I3byzknb96ojXpXUp xlsxWkYkV4AnmOwjJEUByvnuRIuuP9j4AsDcGz9GW3klb7tIO3MzE5rVuewi2Qp2pO cvC99Grhqb7/Azhwm7dk9+IDo/crbeloSM40ecGTSKW0c8ix2DYZ+VwcoSLYgYCHAK eW1U88dFw7jyoSAqIITEJfZlDvkeeBx5URecupCW3YEdpzTCSLk+cDeY+9BwxfUpJA CEs6IgHRiddbg== From: Will Deacon To: linux-kernel@vger.kernel.org Cc: kernel-team@android.com, Will Deacon , iommu@lists.linux.dev, Christoph Hellwig , Marek Szyprowski , Robin Murphy , Petr Tesarik , Dexuan Cui , Nicolin Chen , Michael Kelley Subject: [PATCH v5 4/6] swiotlb: Fix alignment checks when both allocation and DMA masks are present Date: Wed, 28 Feb 2024 13:39:28 +0000 Message-Id: <20240228133930.15400-5-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20240228133930.15400-1-will@kernel.org> References: <20240228133930.15400-1-will@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1792150264407655267 X-GMAIL-MSGID: 1792150264407655267 Nicolin reports that swiotlb buffer allocations fail for an NVME device behind an IOMMU using 64KiB pages. This is because we end up with a minimum allocation alignment of 64KiB (for the IOMMU to map the buffer safely) but a minimum DMA alignment mask corresponding to a 4KiB NVME page (i.e. preserving the 4KiB page offset from the original allocation). If the original address is not 4KiB-aligned, the allocation will fail because swiotlb_search_pool_area() erroneously compares these unmasked bits with the 64KiB-aligned candidate allocation. Tweak swiotlb_search_pool_area() so that the DMA alignment mask is reduced based on the required alignment of the allocation. Fixes: 82612d66d51d ("iommu: Allow the dma-iommu api to use bounce buffers") Reported-by: Nicolin Chen Link: https://lore.kernel.org/r/cover.1707851466.git.nicolinc@nvidia.com Tested-by: Nicolin Chen Reviewed-by: Michael Kelley Signed-off-by: Will Deacon --- kernel/dma/swiotlb.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index c20324fba814..c381a7ed718f 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -981,8 +981,7 @@ static int swiotlb_search_pool_area(struct device *dev, struct io_tlb_pool *pool dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(dev, pool->start) & boundary_mask; unsigned long max_slots = get_max_slots(boundary_mask); - unsigned int iotlb_align_mask = - dma_get_min_align_mask(dev) & ~(IO_TLB_SIZE - 1); + unsigned int iotlb_align_mask = dma_get_min_align_mask(dev); unsigned int nslots = nr_slots(alloc_size), stride; unsigned int offset = swiotlb_align_offset(dev, orig_addr); unsigned int index, slots_checked, count = 0, i; @@ -993,6 +992,14 @@ static int swiotlb_search_pool_area(struct device *dev, struct io_tlb_pool *pool BUG_ON(!nslots); BUG_ON(area_index >= pool->nareas); + /* + * Ensure that the allocation is at least slot-aligned and update + * 'iotlb_align_mask' to ignore bits that will be preserved when + * offsetting into the allocation. + */ + alloc_align_mask |= (IO_TLB_SIZE - 1); + iotlb_align_mask &= ~alloc_align_mask; + /* * For mappings with an alignment requirement don't bother looping to * unaligned slots once we found an aligned one.