linux-kernel - Re: [PATCH v5 06/10] x86/hyper-v: implement rep hypercalls

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Date:   Tue, 30 May 2017 19:33:39 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Vitaly Kuznetsov <vkuznets@...hat.com>
Cc:     "x86@...nel.org" <x86@...nel.org>, devel@...uxdriverproject.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "K. Y. 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>,
        Jork Loeser <Jork.Loeser@...rosoft.com>,
        Simon Xiao <sixiao@...rosoft.com>,
        Andy Lutomirski <luto@...nel.org>
Subject: Re: [PATCH v5 06/10] x86/hyper-v: implement rep hypercalls

On Tue, May 30, 2017 at 2:34 PM, Vitaly Kuznetsov <vkuznets@...hat.com> wrote:
> Rep hypercalls are normal hypercalls which perform multiple actions at
> once. Hyper-V guarantees to return exectution to the caller in not more
> than 50us and the caller needs to use hypercall continuation. Touch NMI
> watchdog between hypercall invocations.
>
> This is going to be used for HvFlushVirtualAddressList hypercall for
> remote TLB flushing.


> +       control |= (u64)varhead_size << 17; /* Variable header size */
> +       control |= (u64)rep_count << 32; /* Rep Count */

> +               control &= U64_MAX >> 16;
> +               control |= (u64)rep_comp << 48;

It might make sense to define magics with appropriate names.

-- 
With Best Regards,
Andy Shevchenko