linux-kernel - Re: [PATCH 06/10] x86: jailhouse: Avoid access of unsupported platform resources

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Date:   Fri, 17 Nov 2017 23:59:42 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Jan Kiszka <jan.kiszka@...mens.com>
cc:     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 06/10] x86: jailhouse: Avoid access of unsupported platform
 resources

On Fri, 17 Nov 2017, Thomas Gleixner wrote:
> On Thu, 16 Nov 2017, Jan Kiszka wrote:
> 
> > From: Jan Kiszka <jan.kiszka@...mens.com>
> > 
> > We don't have CMOS access, thus we can't set the warm-reset vectors in
> 
> s/We/A jailhouse cell/ or s/We/A jailhouse guest/
> 
> > do_boot_cpu. There is no RTC, thus also no wall clock. Furthermore,
> > there are no ISA IRQs and no PIC. So fill the platform callbacks
> > accordingly.
>   
> > +static void jailhouse_get_wallclock(struct timespec *now)
> > +{
> > +	memset(now, 0, sizeof(*now));
> > +}
> 
> > @@ -1006,7 +1007,8 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle,
> >  	 * the targeted processor.
> >  	 */
> >  
> > -	if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
> > +	if (get_uv_system_type() != UV_NON_UNIQUE_APIC &&
> > +	    !jailhouse_paravirt()) {
> >  
> >  		pr_debug("Setting warm reset code and vector.\n");
> 
> Adding more here might justify a function pointer in x86_platform_ops. Not
> sure though, but we have an increasing amount of xen()/kvm()/whatever
> conditionals popping up all over the place. And now you add jailhouse()
> ones :)

Actually we don't want a function pointer as we would need two. A simple
flag would be sufficient.

Thanks,

	tglx