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Date:   Tue, 1 Feb 2022 20:02:12 +0100
From:   Borislav Petkov <bp@alien8.de>
To:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc:     tglx@linutronix.de, mingo@redhat.com, dave.hansen@intel.com,
        luto@kernel.org, peterz@infradead.org,
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        hpa@zytor.com, jgross@suse.com, jmattson@google.com,
        joro@8bytes.org, jpoimboe@redhat.com, knsathya@kernel.org,
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        tony.luck@intel.com, vkuznets@redhat.com, wanpengli@tencent.com,
        x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCHv2 11/29] x86/boot: Allow to hook up alternative port I/O
 helpers
Message-ID: <YfmDtF6WXBdBVGCB@zn.tnic>
References: <20220124150215.36893-1-kirill.shutemov@linux.intel.com>
 <20220124150215.36893-12-kirill.shutemov@linux.intel.com>
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In-Reply-To: <20220124150215.36893-12-kirill.shutemov@linux.intel.com>
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On Mon, Jan 24, 2022 at 06:01:57PM +0300, Kirill A. Shutemov wrote:
> Port I/O instructions trigger #VE in the TDX environment. In response to
> the exception, kernel emulates these instructions using hypercalls.
> 
> But during early boot, on the decompression stage, it is cumbersome to
> deal with #VE. It is cleaner to go to hypercalls directly, bypassing #VE
> handling.
> 
> Add a way to hook up alternative port I/O helpers in the boot stub.
> All port I/O operations are routed via 'pio_ops'. By default 'pio_ops'
> initialized with native port I/O implementations.

I see that you like to talk about what a patch is doing in the commit
message but there's really no need for it - that's visible from the diff
itself, hopefully.

So talk about the *why* instead, pls.

> This is a preparation patch. The next patch will override 'pio_ops' if
> the kernel booted in the TDX environment.

That's also not needed.

The rest LGTM.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette