From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) (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 170E21AB525; Thu, 24 Oct 2024 08:31:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.187 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729758713; cv=none; b=WYnSrTBZwNCH++pKbTkurpjrT43GE7kKLZXz+0puCaC3ZfqsPxE9QwqQNshT6JDMfD0mqcZ1DsRgYwiRALYGJaEmfnZzAe49pm7MAK1yTgVYGC+PDrNj6RWJzhu2edNsb7/J+ufRxXBz8UT3Gmj1KLX8eFj7pBs8k/4dmvr9JOw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729758713; c=relaxed/simple; bh=BF17VSasFWu3ct5Xtw3fwn5TGMxFxg37MvwZ9SW8E3s=; h=Message-ID:Date:MIME-Version:CC:Subject:To:References:From: In-Reply-To:Content-Type; b=Sty+5b6u4kmpp1AtyWrGBQ89Z+AhjwyYjaOUbOJ2e9xZsoMNn4/0xcCV+zxtllfU339RdkncViD17ntkgDhDbZdJ3vOWaSStUtMe36KAz1iQGqeW2DC3TeZdHz81BhXturZoedUYQzCOkvGQQlEFSQMW7X7PXZ/XKt5Z2Ca1Ppo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.48]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4XYzc94VwCz10Nyq; Thu, 24 Oct 2024 16:29:45 +0800 (CST) Received: from kwepemm000007.china.huawei.com (unknown [7.193.23.189]) by mail.maildlp.com (Postfix) with ESMTPS id BBCC318009B; Thu, 24 Oct 2024 16:31:48 +0800 (CST) Received: from [10.67.120.192] (10.67.120.192) by kwepemm000007.china.huawei.com (7.193.23.189) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Thu, 24 Oct 2024 16:31:47 +0800 Message-ID: Date: Thu, 24 Oct 2024 16:31:46 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird CC: , , , , , , Subject: Re: [PATCH V2 net 1/9] net: hns3: default enable tx bounce buffer when smmu enabled To: Paolo Abeni , , , , , References: <20241018101059.1718375-1-shaojijie@huawei.com> <20241018101059.1718375-2-shaojijie@huawei.com> <50874428-b4ef-4e65-b60b-1bd917f1933c@redhat.com> From: Jijie Shao In-Reply-To: <50874428-b4ef-4e65-b60b-1bd917f1933c@redhat.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemm000007.china.huawei.com (7.193.23.189) on 2024/10/24 16:26, Paolo Abeni wrote: > On 10/18/24 12:10, Jijie Shao wrote: >> From: Peiyang Wang >> >> The SMMU engine on HIP09 chip has a hardware issue. >> SMMU pagetable prefetch features may prefetch and use a invalid PTE >> even the PTE is valid at that time. This will cause the device trigger >> fake pagefaults. The solution is to avoid prefetching by adding a >> SYNC command when smmu mapping a iova. But the performance of nic has a >> sharp drop. Then we do this workaround, always enable tx bounce buffer, >> avoid mapping/unmapping on TX path. >> >> This issue only affects HNS3, so we always enable >> tx bounce buffer when smmu enabled to improve performance. >> >> Signed-off-by: Peiyang Wang >> Signed-off-by: Jian Shen >> Signed-off-by: Jijie Shao > I'm sorry to nick pick on somewhat small details, but we really need a > fixes tag here to make 110% clear is a bugfix. I guess it could be the > commit introducing the support for the buggy H/W. > > Thanks, > > Paolo I have a little doubt that this patch is about H/W problem, so how can we write the the fixes tag? Thanks, Jijie Shao