From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 64D8832B98A for ; Fri, 6 Feb 2026 17:36:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770399369; cv=none; b=PEeztd5234UjLx5M56Hmj0TcikWEgSz35fWzsIpiK0wxTomSrlLQP5BE6gZi2gFsC0xXO3Vp0iCG5jkae7IE0n1jzxSOH6F/OMInBffXrU9ANQK/T9+G/X9z1SUwD3s3BxOUd3ATP1TSZSl1/jvJLnYrR2OXulfLkWXFOYxd9Gg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770399369; c=relaxed/simple; bh=vfmXj24uN06y/FV/u4F7dOzRzFvyFmbgX5UlVHxmbYQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=MrUUJAG0m1mjk4sAHnQ6ACcxgB9hCTMNcFdelTV3pEbb8XqADGTtO6vNtMufeUSRAqJnIjp0hnu3TDMGDc0U9LVxN6Pzrmh/E1Ja1qRErrehAFoiRYhehF5uyOIl0SCu/E8+mUBkLRnzdOPLVCt+tmigT9cYj+Oa5AECdF7HGx0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 4D352339; Fri, 6 Feb 2026 09:36:01 -0800 (PST) Received: from [10.57.54.83] (unknown [10.57.54.83]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9DB4E3F778; Fri, 6 Feb 2026 09:36:06 -0800 (PST) Message-ID: <9c15f736-9737-400f-a757-2640d07ba551@arm.com> Date: Fri, 6 Feb 2026 17:36:04 +0000 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 v2] iommu/arm-smmu-v3: Restrict MMU-700 errata 2268618 and 2812531 to affected To: Zhiyuan Dai , Will Deacon , Joerg Roedel Cc: linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org References: <20260206-smmuv3-v2-1-f381a2125392@phytium.com.cn> From: Robin Murphy Content-Language: en-GB In-Reply-To: <20260206-smmuv3-v2-1-f381a2125392@phytium.com.cn> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2026-02-06 8:18 am, Zhiyuan Dai wrote: > According to SDEN-1786925, Arm errata 2268618 and 2812531 are present in > r0p0, r0p1, and r1p0, and fixed in r1p1. > > Introduce this patch to avoid performance degradation caused by > restricting features on unaffected revisions. > > Signed-off-by: Zhiyuan Dai > --- > Changelog: > - Change the revision threshold from < 0 to < 1 to correctly. > - Link to v1: https://lore.kernel.org/linux-iommu/3f22f7b8-449c-40d9-b4c8-fff3e520d563@arm.com/raw > --- > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > index d16d35c78c06..d5c35be5c858 100644 > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > @@ -4272,11 +4272,13 @@ static void arm_smmu_device_iidr_probe(struct arm_smmu_device *smmu) > smmu->features &= ~ARM_SMMU_FEAT_NESTING; > break; > case IIDR_PRODUCTID_ARM_MMU_700: > - /* Arm erratum 2812531 */ > - smmu->features &= ~ARM_SMMU_FEAT_BTM; > - smmu->options |= ARM_SMMU_OPT_CMDQ_FORCE_SYNC; > - /* Arm errata 2268618, 2812531 */ > - smmu->features &= ~ARM_SMMU_FEAT_NESTING; > + if (variant <= 1 && revision < 1) { This still breaks r0p1, and you've not addressed the other point I made... I've now dug up the old branch where I started my own patch (back in May 2024, yikes!), and gone through the newer errata for MMU-700 plus the newer MMU S3 and MMU L1 products that have also inherited some of its bugs - I'll finish writing up a cover letter for that and share it on Monday. Thanks, Robin. > + /* Arm erratum 2812531 */ > + smmu->features &= ~ARM_SMMU_FEAT_BTM; > + smmu->options |= ARM_SMMU_OPT_CMDQ_FORCE_SYNC; > + /* Arm errata 2268618, 2812531 */ > + smmu->features &= ~ARM_SMMU_FEAT_NESTING; > + } > break; > } > break; > > --- > base-commit: b7ff7151e653aa296ab6c5495b2c1ab7c21eb250 > change-id: 20260206-smmuv3-a88772377c20 > > Best regards,