linux-kernel - Re: [PATCH 03/10] x86: jailhouse: Enable APIC and SMP support

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Message-ID: <20171120143950.GC24312@char.us.oracle.com>
Date:   Mon, 20 Nov 2017 09:39:50 -0500
From:   Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Jan Kiszka <jan.kiszka@...mens.com>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        jailhouse-dev@...glegroups.com
Subject: Re: [PATCH 03/10] x86: jailhouse: Enable APIC and SMP support

On Fri, Nov 17, 2017 at 11:42:02PM +0100, Thomas Gleixner wrote:
> On Thu, 16 Nov 2017, Jan Kiszka wrote:
> 
> Just noticed, that all prefixes should be 'x86/jailhouse:' please
> 
> > +static unsigned int x2apic_get_apic_id(unsigned long id)
> > +{
> > +        return id;
> > +}
> > +
> >  static void __init jailhouse_init_platform(void)
> >  {
> >  	u64 pa_data = boot_params.hdr.setup_data;
> >  	struct jailhouse_setup_data *data;
> > +	unsigned int cpu;
> >  
> >  	data = early_memremap(pa_data, sizeof(*data));
> >  
> > @@ -59,6 +66,23 @@ static void __init jailhouse_init_platform(void)
> >  	    data->compatible_version > SETUP_REQUIRED_VERSION)
> >  		panic("Jailhouse: Unsupported setup data structure");
> >  
> > +#ifdef CONFIG_X86_X2APIC
> > +	/*
> > +	 * Register x2APIC handlers early. We need them when running
> > +	 * register_lapic_address.
> > +	 */
> > +	if (x2apic_enabled()) {
> > +		apic->read = native_apic_msr_read;
> > +		apic->write = native_apic_msr_write;
> > +		apic->get_apic_id = x2apic_get_apic_id;
> 
> Uurgh. That looks hacky.

Could just create a new APIC driver (which would call most of these)?

> 
> > +	}
> > +#endif
> > +	register_lapic_address(0xfee00000);
> 
> No need to do all of this here. The right thing to do is to override
> 
>    x86_init.mpparse.get_smp_config
> 
> which is invoked after generic_apic_probe() which should select
> x2apic_phys, but I might be wrong.
> 
> 
> > +	for (cpu = 0; cpu < data->num_cpus; cpu++)
> > +		generic_processor_info(data->cpu_ids[cpu],
> > +				       boot_cpu_apic_version);
> 
> Please add brackets around multi line statements.
> 
> Thanks,
> 
> 	tglx