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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Juergen Gross <jgross@suse.com>,
        LKML <linux-kernel@vger.kernel.org>
Cc:     x86@kernel.org, Andrew Cooper <andrew.cooper3@citrix.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Wei Liu <wei.liu@kernel.org>,
        Arjan van de Ven <arjan@linux.intel.com>,
        Michael Kelley <mikelley@microsoft.com>,
        Peter Keresztes Schmidt <peter@keresztesschmidt.de>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>
Subject: Re: [patch V2 50/58] x86/apic: Provide common init infrastructure
In-Reply-To: <b4f0e874-1e35-e523-8e5a-710bc54af52d@suse.com>
References: <20230724131206.500814398@linutronix.de>
 <20230724132047.554355840@linutronix.de>
 <abfa4548-4367-d8fa-f23f-b2ca4a912258@suse.com> <87v8e0nskd.ffs@tglx>
 <b4f0e874-1e35-e523-8e5a-710bc54af52d@suse.com>
Date:   Mon, 31 Jul 2023 17:48:47 +0200
Message-ID: <87pm48nktc.ffs@tglx>
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On Mon, Jul 31 2023 at 15:10, Juergen Gross wrote:
> On 31.07.23 15:01, Thomas Gleixner wrote:
>>>    apic_driver(xen_pv_apic);
>> 
>> I wonder whether this explicit install is actually needed at all.
>> Shouldn't the driver be installed via the APIC probing mechanism
>> automagically?
>
> Only in case x86_init.irq.intr_mode_init is set appropriately. Today it is
> a nop for Xen PV, but that can be changed. I'll have a look.

You could simply set that callback to default_setup_apic_routing() and
be done with it.