From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 3FF95390C98; Mon, 30 Mar 2026 04:18:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774844312; cv=none; b=KR8XspKlO5IgB8DTdyMO5jWcdtShGVDhSFwWrarGg+zDQdk6zqjSIzJHiXZn7ZMEDX+gUTwNdUnyEPBXaCVd31YFBvjWjnQrFChHl4JYNxQ2ve7TyZ6rKVzMD0jzWUGbR/6IhM1tdVyyTlXWRpzM1UPPWexiBQxsKSB4xl1geLU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774844312; c=relaxed/simple; bh=BeOtCXTMCB7YaaO1WBZF71yVhqEr3ar112uNfVOk5Cw=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=N84qNr4mCqGsABCuqwLH2Ie/CmEixrcrC+mq8I7jRtDcjRoJRSVRqLH2vAMd2Ds971MEkiJLWfosSX8kvhfcR/01Nki0BHArLz9O6+f/+6trY9o2fr3BPF0wlwdp6jMpAa7MxTXKKDFyQCXTqa9XK+PCFVKadOtAiTxRqPOiyEM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=J8kcADn4; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="J8kcADn4" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:To:Subject:MIME-Version:Date: Message-ID:Sender:Reply-To:Cc:Content-ID:Content-Description; bh=sgEMrjrD66wL+BwansuR9C1q0Xf/+QldV+6TTBn3FIw=; b=J8kcADn4FJBooep86FOm/F03ej iUppKOu28L4LhSL+8+X3P5b/QPYw8NrtH/Plj65cjjLeuf1+b8Y7Bm9PAJ5M118HINjH0G1nGgYEw K5wi+1jcvPDHUssDRsZw82ecZbIbZUiqiLZ5SuAKk2DX2az3CY9ygKwV0qEtE4JU7AM13e5mrxh4K UGrmaZQcqZXRcOVxbtZyU7ni1Kd0SgfrxK7vGkJVgoYaVKpJXPA8fpi3WNkDnTD2tSPAIZWgkn/yF 3LVHlfrqujkqXCsy/S6hwy+tJxhxEe5pI8n9CcTlo5ZYzVLmtjIlx71ZsI34WtvH9bpCNH8PAerpw wHOrpikA==; Received: from [50.53.43.113] (helo=[192.168.254.34]) by bombadil.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1w744m-0000000AaxX-25OI; Mon, 30 Mar 2026 04:18:08 +0000 Message-ID: Date: Sun, 29 Mar 2026 21:18:06 -0700 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: =?UTF-8?B?UmU6IOetlOWkjTogW+WklumDqOmCruS7tl0gUmU6IFtQQVRDSF0gZG9j?= =?UTF-8?Q?s=3A_kernel-parameters=3A_fix_architecture_alignment_for_pt=2C_no?= =?UTF-8?Q?pt=2C_and_nobypass?= To: "Li,Rongqing(ACG CCN)" , Jonathan Corbet , Shuah Khan , Andrew Morton , Borislav Petkov , Peter Zijlstra , Feng Tang , Pawan Gupta , Dapeng Mi , Kees Cook , Marco Elver , "Paul E . McKenney" , Askar Safin , Bjorn Helgaas , Sohil Mehta , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <20260326074658.1899-1-lirongqing@baidu.com> <16386e7715284b22b5f72e7106ed5619@baidu.com> Content-Language: en-US From: Randy Dunlap In-Reply-To: <16386e7715284b22b5f72e7106ed5619@baidu.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 3/29/26 8:08 PM, Li,Rongqing(ACG CCN) wrote: > > >> -----邮件原件----- >> 发件人: Randy Dunlap >> 发送时间: 2026年3月27日 0:08 >> 收件人: Li,Rongqing(ACG CCN) ; Jonathan Corbet >> ; Shuah Khan ; Andrew Morton >> ; Borislav Petkov ; Peter Zijlstra >> ; Feng Tang ; Pawan >> Gupta ; Dapeng Mi >> ; Kees Cook ; Marco Elver >> ; Paul E . McKenney ; Askar Safin >> ; Bjorn Helgaas ; Sohil Mehta >> ; linux-doc@vger.kernel.org; >> linux-kernel@vger.kernel.org >> 主题: [外部邮件] Re: [PATCH] docs: kernel-parameters: fix architecture >> alignment for pt, nopt, and nobypass >> >> Hi, >> >> On 3/26/26 12:46 AM, lirongqing wrote: >>> From: Li RongQing >>> >>> Commit ab0e7f20768a ("Documentation: Merge x86-specific boot options >>> doc into kernel-parameters.txt") introduced a formatting regression >>> where architecture tags were placed on separate lines with broken >> indentation. >>> This caused the 'nopt' [X86] parameter to appear as if it belonged to >>> the [PPC/POWERNV] section. >>> >>> Fix the formatting by placing the architecture tags on the same line >>> as their respective parameters ('pt', 'nopt', and 'nobypass') and >>> restoring proper indentation. >>> >>> Fixes: ab0e7f20768a ("Documentation: Merge x86-specific boot options >>> doc into kernel-parameters.txt") >>> Signed-off-by: Li RongQing >>> --- >>> Documentation/admin-guide/kernel-parameters.txt | 9 +++------ >>> 1 file changed, 3 insertions(+), 6 deletions(-) >>> >>> diff --git a/Documentation/admin-guide/kernel-parameters.txt >>> b/Documentation/admin-guide/kernel-parameters.txt >>> index 03a5506..dc1c5bd 100644 >>> --- a/Documentation/admin-guide/kernel-parameters.txt >>> +++ b/Documentation/admin-guide/kernel-parameters.txt >>> @@ -2615,12 +2615,9 @@ Kernel parameters >>> Intel machines). This can be used to prevent the usage >>> of an available hardware IOMMU. >>> >>> - [X86] >>> - pt >>> - [X86] >>> - nopt >>> - [PPC/POWERNV] >>> - nobypass >>> + pt [X86] >>> + nopt [X86] >>> + nobypass [PPC/POWERNV] >>> Disable IOMMU bypass, using IOMMU for PCI devices. >>> >>> [X86] >> >> This looks good as far as it goes, but there are still some problems IMO. >> >> These are all iommu= options, but iommu says that it's for [X86,EARLY]. >> No PPC/POWERNV mentioned there. > > I think [PPC/POWERNV] should not be added to the main iommu= header. Since that header is already tagged as [X86, EARLY], adding PowerPC there would imply all subsequent options are cross-platform. Instead, it is cleaner to keep the main header as X86-specific and explicitly tag the individual nobypass option for [PPC/POWERNV]. This avoids the need to redundantly label every other X86-only option (like pt or nopt) within the section. > >> >> Then immediately following nobypass, there is this: >> [X86] >> AMD Gart HW IOMMU-specific options: >> >> which is also in questionable format. The [X86] isn't needed at all IMO, or if it's >> desirable, those 2 lines should be on one line. >> > You are right , [X86] isn't needed , How about to remove the [X86], like below > > Documentation/kernel-parameters: fix architecture alignment for pt, nopt, and nobypass > > Commit ab0e7f20768a ("Documentation: Merge x86-specific boot options doc > into kernel-parameters.txt") introduced a formatting regression where > architecture tags were placed on separate lines with broken indentation. > This caused the 'nopt' [X86] parameter to appear as if it belonged to > the [PPC/POWERNV] section. > > Furthermore, since the main 'iommu=' parameter heading already specifies > it is for [X86, EARLY], the subsequent standalone [X86] tags for 'pt', > 'nopt', and the AMD GART options are redundant and clutter the > documentation. > > Clean up the formatting by removing these redundant tags and properly > attributing the 'nobypass' option to [PPC/POWERNV]. > > Fixes: ab0e7f20768a ("Documentation: Merge x86-specific boot options doc into kernel-parameters.txt") > Signed-off-by: Li RongQing > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 03a5506..5253c23 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -2615,15 +2615,11 @@ Kernel parameters > Intel machines). This can be used to prevent the usage > of an available hardware IOMMU. > > - [X86] > pt > - [X86] > nopt > - [PPC/POWERNV] > - nobypass > + nobypass [PPC/POWERNV] > Disable IOMMU bypass, using IOMMU for PCI devices. > > - [X86] > AMD Gart HW IOMMU-specific options: > > > [Li,Rongqing] > Yes, LGTM. Thanks. Acked-by: Randy Dunlap -- ~Randy