linux-kernel - Re: [PATCH 1/3] x86/apic: Drop apic::delivery

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Message-ID: <8734xljprd.ffs@tglx>
Date:   Sat, 04 Nov 2023 20:13:26 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Andrew Cooper <andrew.cooper3@...rix.com>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>, Steve Wahl <steve.wahl@....com>,
        Justin Ernst <justin.ernst@....com>,
        Kyle Meyer <kyle.meyer@....com>,
        Dimitri Sivanich <dimitri.sivanich@....com>,
        Russ Anderson <russ.anderson@....com>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        "K. Y. Srinivasan" <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Wei Liu <wei.liu@...nel.org>, Dexuan Cui <decui@...rosoft.com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>
Cc:     linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        linux-hyperv@...r.kernel.org, linux-pci@...r.kernel.org,
        Andrew Cooper <andrew.cooper3@...rix.com>
Subject: Re: [PATCH 1/3] x86/apic: Drop apic::delivery_mode

On Thu, Nov 02 2023 at 12:26, Andrew Cooper wrote:
> This field is set to APIC_DELIVERY_MODE_FIXED in all cases, and is read
> exactly once.  Fold the constant in uv_program_mmr() and drop the field.
>
> Searching for the origin of the stale HyperV comment reveals commit
> a31e58e129f7 ("x86/apic: Switch all APICs to Fixed delivery mode") which
> notes:
>
>   As a consequence of this change, the apic::irq_delivery_mode field is
>   now pointless, but this needs to be cleaned up in a separate patch.
>
> 6 years is long enough for this technical debt to have survived.

Guilty as charged. :)

Thanks for spotting this and cleaning it up!

       tglx