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From:   Adam Dunlap <acdunlap@google.com>
Date:   Mon, 3 Oct 2022 16:07:22 -0700
Message-ID: <CAMBK9=a4mR65urS3f7=V-Ukpaeqpem2M7B2B22VPC1ufES4iXg@mail.gmail.com>
Subject: Re: [PATCH v2 RESEND] x86/asm: Force native_apic_mem_read to use mov
To:     Peter Gonda <pgonda@google.com>
Cc:     Sean Christopherson <seanjc@google.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "the arch/x86 maintainers" <x86@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Ben Dooks <ben-linux@fluff.org>,
        LKML <linux-kernel@vger.kernel.org>, llvm@lists.linux.dev,
        Jacob Xu <jacobhxu@google.com>,
        Alper Gun <alpergun@google.com>, Marc Orr <marcorr@google.com>,
        "Lendacky, Thomas" <Thomas.Lendacky@amd.com>
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[resent with plain text]

Thanks for all the responses. Is the consensus that we should use the
readl function here or instead use inline assembly directly as in the patch
I originally sent out:

asm_inline("movl %1, %0" : "=r"(out) : "m"(*addr));

? The readl function has this exact same code, I'm just not sure
which version fits better stylistically.


On Mon, Oct 3, 2022 at 4:01 PM Adam Dunlap <acdunlap@google.com> wrote:
>
> Thanks for all the responses. Is the consensus that we should use the
> readl function here or instead use inline assembly directly as in the patch
> I originally sent out:
>
> asm_inline("movl %1, %0" : "=r"(out) : "m"(*addr));
>
> ? The readl function has this exact same code, I'm just not sure
> which version fits better stylistically.