Subject: Re: [PATCH] x86/paravirt: Fix build PARAVIRT_XXL=y without XEN_PV
To:     Lai Jiangshan <jiangshanlai+lkml@gmail.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Peter Zijlstra <peterz@infradead.org>, X86 ML <x86@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Deep Shah <sdeep@vmware.com>,
        "VMware, Inc." <pv-drivers@vmware.com>
References: <20211117181439.4368-1-kirill.shutemov@linux.intel.com>
 <CAJhGHyBRcAg33DxxGGpbnT+O7CGKp6Ktr3PtCZ0j50oTJ4fgrg@mail.gmail.com>
 <20211119102048.hjm46edvhryjgluy@box.shutemov.name>
 <CAJhGHyA0TB-OE0guLFzbyOTcOjLZ8EDJRXasHoWy7OvopK0xkg@mail.gmail.com>
From:   Juergen Gross <jgross@suse.com>
Message-ID: <b09f3263-61a4-4b3e-948e-068e5806ffa1@suse.com>
Date:   Mon, 22 Nov 2021 13:55:26 +0100
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From: Juergen Gross <jgross@suse.com>
To: Lai Jiangshan <jiangshanlai+lkml@gmail.com>,
 "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
 Borislav Petkov <bp@alien8.de>,
 Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>,
 Andi Kleen <ak@linux.intel.com>, Dave Hansen <dave.hansen@intel.com>,
 Peter Zijlstra <peterz@infradead.org>, X86 ML <x86@kernel.org>,
 LKML <linux-kernel@vger.kernel.org>,
 "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
 Deep Shah <sdeep@vmware.com>, "VMware, Inc." <pv-drivers@vmware.com>
Message-ID: <b09f3263-61a4-4b3e-948e-068e5806ffa1@suse.com>
Subject: Re: [PATCH] x86/paravirt: Fix build PARAVIRT_XXL=y without XEN_PV
References: <20211117181439.4368-1-kirill.shutemov@linux.intel.com>
 <CAJhGHyBRcAg33DxxGGpbnT+O7CGKp6Ktr3PtCZ0j50oTJ4fgrg@mail.gmail.com>
 <20211119102048.hjm46edvhryjgluy@box.shutemov.name>
 <CAJhGHyA0TB-OE0guLFzbyOTcOjLZ8EDJRXasHoWy7OvopK0xkg@mail.gmail.com>
In-Reply-To: <CAJhGHyA0TB-OE0guLFzbyOTcOjLZ8EDJRXasHoWy7OvopK0xkg@mail.gmail.com>

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On 20.11.21 02:23, Lai Jiangshan wrote:
> On Fri, Nov 19, 2021 at 6:20 PM Kirill A. Shutemov <kirill@shutemov.nam=
e> wrote:
>=20
>>> It is part of what CONFIG_PARAVIRT_XXL was designed for to enable
>>> pv-aware INTERRUPT_RETURN.
>>
>> That's very vague statement.
>>
>> Could you elaborate on what is wrong with proposed fix?
>>
>=20
> Although CONFIG_PARAVIRT_XXL is enabled only when XEN, but they are
> separated configs.  There is no wrong with the patch, but it is not
> justified to narrow the scope of INTERRUPT_RETURN.

xen_iret is defined only with CONFIG_XEN_PV, so using that in
INTERRUPT_RETURN only in case CONFIG_XEN_PV is defined is absolutely
the right thing to do.

In case another user of INTERRUPT_RETURN would come up, it would
need to be changed again anyway.


Juergen

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