答复: [外部邮件] Re: [PATCH] docs: kernel-parameters: fix architecture alignment for pt, nopt, and nobypass

["Li,Rongqing(ACG CCN)" <lirongqing@baidu.com>]

> -----邮件原件-----
> 发件人: Randy Dunlap <rdunlap@infradead.org>
> 发送时间: 2026年3月27日 0:08
> 收件人: Li,Rongqing(ACG CCN) <lirongqing@baidu.com>; Jonathan Corbet
> <corbet@lwn.net>; Shuah Khan <skhan@linuxfoundation.org>; Andrew Morton
> <akpm@linux-foundation.org>; Borislav Petkov <bp@alien8.de>; Peter Zijlstra
> <peterz@infradead.org>; Feng Tang <feng.tang@linux.alibaba.com>; Pawan
> Gupta <pawan.kumar.gupta@linux.intel.com>; Dapeng Mi
> <dapeng1.mi@linux.intel.com>; Kees Cook <kees@kernel.org>; Marco Elver
> <elver@google.com>; Paul E . McKenney <paulmck@kernel.org>; Askar Safin
> <safinaskar@gmail.com>; Bjorn Helgaas <bhelgaas@google.com>; Sohil Mehta
> <sohil.mehta@intel.com>; 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 <lirongqing@baidu.com>
> >
> > 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 <lirongqing@baidu.com>
> > ---
> >  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 <lirongqing@baidu.com>

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:

                <size>
[Li,Rongqing] 


> Anyway, for this patch:
> Acked-by: Randy Dunlap <rdunlap@infradead.org>
> 
> Thanks.
> 
> --
> ~Randy