linux-kernel - Re: [PATCH v10 0/9] Hyper-V: paravirtualized remote TLB flushing and hypercall improvements

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Date:   Thu, 10 Aug 2017 19:00:12 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     Ingo Molnar <mingo@...nel.org>
Cc:     x86@...nel.org, devel@...uxdriverproject.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>,
        Andy Shevchenko <andy.shevchenko@...il.com>
Subject: Re: [PATCH v10 0/9] Hyper-V: paravirtualized remote TLB flushing and hypercall improvements

Ingo Molnar <mingo@...nel.org> writes:

> I'm getting this build failure with this series:
>
> arch/x86/hyperv/mmu.c: In function ‘hyperv_setup_mmu_ops’:
> arch/x86/hyperv/mmu.c:256:3: error: ‘pv_mmu_ops’ undeclared (first use in this 
> function)
>    pv_mmu_ops.flush_tlb_others = hyperv_flush_tlb_others;
>    ^
>
> with the attached (rand-)config.
>

> # CONFIG_PARAVIRT is not set

Ouch, this is definitely required for the new feature. Sorry :-(

I think the best way to handle this (and having in mind upcoming PV
spinlocks for Hyper-V) is something like

diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index c29cd5387a35..50b89ea0e60f 100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -3,6 +3,7 @@ menu "Microsoft Hyper-V guest support"
 config HYPERV
        tristate "Microsoft Hyper-V client drivers"
        depends on X86 && ACPI && PCI && X86_LOCAL_APIC && HYPERVISOR_GUEST
+       select PARAVIRT
        help
          Select this option to run Linux as a Hyper-V client operating
          system.

added to PATCH7 of the series. In case nobody objects, would you like me
to resend the patch or do the whole v11 submission?

Thanks and sorry for the breakage,

-- 
  Vitaly