linux-kernel - Re: [PATCH v5 08/10] x86/hyper-v: use hypercall for remote TLB flush

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Message-ID: <CAHp75VcOAK_mMEc7d3ff54K+t0FzbMC0_7=jBTGzb=hgY8-omg@mail.gmail.com>
Date:   Tue, 30 May 2017 22:19:58 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Jork Loeser <Jork.Loeser@...rosoft.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "devel@...uxdriverproject.org" <devel@...uxdriverproject.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        KY Srinivasan <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Simon Xiao <sixiao@...rosoft.com>,
        Andy Lutomirski <luto@...nel.org>
Subject: Re: [PATCH v5 08/10] x86/hyper-v: use hypercall for remote TLB flush

On Tue, May 30, 2017 at 10:17 PM, Jork Loeser <Jork.Loeser@...rosoft.com> wrote:

>> > +#define HV_FLUSH_ALL_PROCESSORS                        0x00000001
>> > +#define HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES    0x00000002
>> > +#define HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY      0x00000004
>> > +#define HV_FLUSH_USE_EXTENDED_RANGE_FORMAT     0x00000008
>>
>> BIT() ?
>
> Certainly a matter of taste.

That's why ? is used, though slightly better to parse the BIT macros
which is also less error prone.

> Given that the Hyper-V spec lists these as hex numbers, I find the explicit numbers appropriate.

Yes, but since it introduces a full set of the flags I would not see
disadvantages by style.

-- 
With Best Regards,
Andy Shevchenko