From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.forwardemail.net (smtp.forwardemail.net [121.127.44.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AAA4F3B6366 for ; Wed, 1 Apr 2026 12:01:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=121.127.44.66 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775044906; cv=none; b=iAN+D6oF173UIvXfmN4VVytcdenWC0gUoeqr+twILmA0xg/iq/jdULAi3Ht/oTzIaxAImE3wqcq7+C9zBQRNJk/qL13zP+RY0lGnYX8qG4oDGwvqJoJIbW7g6z+45ZYHMG57yR7Ue9h5JJxhQh1j0/xcZd9lXgULcBkqTnNvSMs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775044906; c=relaxed/simple; bh=pvVv7D8UQ2G4Mw/nmqu8vkM8+Pe0lRNW4/kqqhlVXbE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=EfAibRgwegcfs6mu+LlqLogZIjHF2fxrqSZOuGA5p4QZ2n4PBcqVe8iT12++Y1bu/+cn8xX0KGQtBy549g48fEAfo5HDKy8I2T5yRClBV9E/+WxzXXJk/nXn5UvBvvhqzGB1ccMxwcjLJxPO2S5UZAL3UAJfkYYnDGvFCmf2baE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=kwiboo.se; spf=pass smtp.mailfrom=fe-bounces.kwiboo.se; dkim=pass (2048-bit key) header.d=kwiboo.se header.i=@kwiboo.se header.b=h77EyTLn; arc=none smtp.client-ip=121.127.44.66 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=kwiboo.se Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fe-bounces.kwiboo.se Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kwiboo.se header.i=@kwiboo.se header.b="h77EyTLn" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kwiboo.se; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: From: References: Cc: To: Subject: MIME-Version: Date: Message-ID; q=dns/txt; s=fe-e1b5cab7be; t=1775044903; bh=SqAh8+J+p74P/kyDkkVzKjpnfMDd7XwXqLzKDtTGffs=; b=h77EyTLn3yo5NqYd/571d+UQlvBEnTHNv7HmkuxN+2dHiwnarRIcEzhCjSNA+Dg5lkFkISGXl 7ebBdsNvjKShc4ezNd6q3lGK/h3+YvY5pGYxAED6DgsWkDh+T5FBvjg6YwewnaP7469VB1rsKQq x/gY/oHz/cvzzwKtp1/Y30mhbwa2h59BqiADjJXWwSAm1ai4bSHHjvg/YsIappNtZ/04b0LUhdn ZJiBsTgse1EVAivspUdMTpt9MCCq0oqU2RJZtSUU7T5MA/ajYMODGR3dzU0W0iL+ZV6TDPw8O5N gep2UyglFTW/DDsyRgqdlFxp/OlgdQ8fD3j2JNRjPjTw== X-Forward-Email-ID: 69ccda55842394fec82951f9 X-Forward-Email-Sender: rfc822; jonas@kwiboo.se, smtp.forwardemail.net, 121.127.44.66 X-Forward-Email-Version: 2.6.64 X-Forward-Email-Website: https://forwardemail.net X-Complaints-To: abuse@forwardemail.net X-Report-Abuse: abuse@forwardemail.net X-Report-Abuse-To: abuse@forwardemail.net Message-ID: Date: Wed, 1 Apr 2026 10:41:54 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] iommu/rockchip: fix page table allocation flags for v2 IOMMU To: Simon , Midgy BALON Cc: iommu@lists.linux.dev, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, heiko@sntech.de, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20260331075010.1463-1-midgy971@gmail.com> <0f285782-b12a-4abd-bca7-b6c549bed59f@rock-chips.com> Content-Language: en-US From: Jonas Karlman In-Reply-To: <0f285782-b12a-4abd-bca7-b6c549bed59f@rock-chips.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Simon, On 4/1/2026 9:48 AM, Simon wrote: > Hi Midgy, > > 在 2026/3/31 15:50, Midgy BALON 写道: >> commit 2a7e6400f72b ("iommu: rockchip: Allocate tables from all >> available memory for IOMMU v2") removed GFP_DMA32 from >> iommu_data_ops_v2, reasoning that RK356x and RK3588 IOMMU v2 hardware >> supports up to 40-bit physical addresses for page tables. However, the >> RK3568 IOMMU page-table walker uses a 32-bit AXI bus: it cannot access >> physical addresses above 4 GB regardless of the address encoding range. >> >> On boards with more than 4 GB of RAM (e.g. 8 GB LPDDR4X), removing >> GFP_DMA32 causes two distinct failure modes: >> >> 1. Direct allocation above 4 GB: iommu_alloc_pages_sz() may return >> memory above 0x100000000. The hardware page-table walker issues a >> bus error trying to dereference those addresses, causing an IOMMU >> fault on the first DMA transaction. > > Which IP block is hitting this? We'd like to take a look on our end. I have seen reports that the NPU MMU on RK3568/RK3566 is having some issue using DTE/PTE with >32-bit addresses, maybe it uses a different MMU hw revision or has some hw errata? >From my own testing at least the VOP2 MMU on RK3568 (and RK3588) was able to handle 40-bit addressable DTE/PTE, hence the original commit 2a7e6400f72b ("iommu: rockchip: Allocate tables from all available memory for IOMMU v2"). As also mentioned in my reply at [1], maybe the NPU MMU has some hw limitation or errata and may need to use a different compatible. [1] https://lore.kernel.org/r/3cd63b3d-1c5e-4a11-856e-c4aeb5d97d55@kwiboo.se/ Regards, Jonas > >> 2. SWIOTLB bounce-buffer poisoning: without GFP_DMA32, page tables land >> above the SWIOTLB window. dma_map_single() with DMA_BIT_MASK(32) >> then bounces them into a buffer below 4 GB. rk_dte_get_page_table() >> returns phys_to_virt() of the bounce buffer address; PTEs are written >> there; the next dma_sync_single_for_device(DMA_TO_DEVICE) copies the >> original (zero) data back over the bounce buffer, silently erasing the >> freshly written PTEs. The IOMMU faults because every PTE reads as zero. > > This probably need a separate patch. One way to fix it would be to track the > original L2 page table base addresses in struct rk_iommu_domain, > then have rk_dte_get_page_table() return the tracked address instead of > deriving it from the DTE. > >> Restore GFP_DMA32 (and DMA_BIT_MASK(32)) for iommu_data_ops_v2, which >> currently only serves "rockchip,rk3568-iommu" in mainline. >> >> Tested on Radxa ROCK 3B (RK3568, 8 GB LPDDR4X): >> - MobileNetV1 via RKNN: 5.8 ms/inference (IOMMU mode) >> - YOLOv5s 640x640 via RKNN: ~57 ms/inference (IOMMU mode) >> - No IOMMU faults, correct inference results >> >> Fixes: 2a7e6400f72b ("iommu: rockchip: Allocate tables from all available memory for IOMMU v2") >> Cc: stable@vger.kernel.org >> Cc: Jonas Karlman >> Signed-off-by: Midgy BALON >> --- >> drivers/iommu/rockchip-iommu.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c >> index 85f3667e797..8b45db29471 100644 >> --- a/drivers/iommu/rockchip-iommu.c >> +++ b/drivers/iommu/rockchip-iommu.c >> @@ -1358,8 +1358,8 @@ static struct rk_iommu_ops iommu_data_ops_v2 = { >> .pt_address = &rk_dte_pt_address_v2, >> .mk_dtentries = &rk_mk_dte_v2, >> .mk_ptentries = &rk_mk_pte_v2, >> - .dma_bit_mask = DMA_BIT_MASK(40), >> - .gfp_flags = 0, >> + .dma_bit_mask = DMA_BIT_MASK(32), >> + .gfp_flags = GFP_DMA32, >> }; >> >> static const struct of_device_id rk_iommu_dt_ids[] = {