Re: [PATCH v2 06/17] x86/hyperv: allocate output arg pages if required

[Wei Liu]

On Thu, Nov 12, 2020 at 04:35:48PM +0100, Vitaly Kuznetsov wrote:
> Wei Liu <wei.liu@xxxxxxxxxx> writes:
[...]
> > @@ -209,14 +219,23 @@ static int hv_cpu_die(unsigned int cpu)
> >  	unsigned int new_cpu;
> >  	unsigned long flags;
> >  	void **input_arg;
> > -	void *input_pg = NULL;
> > +	void *pg;
> >  
> >  	local_irq_save(flags);
> >  	input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
> > -	input_pg = *input_arg;
> > +	pg = *input_arg;
> >  	*input_arg = NULL;
> > +
> > +	if (hv_root_partition) {
> > +		void **output_arg;
> > +
> > +		output_arg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
> > +		*output_arg = NULL;
> > +	}
> > +
> >  	local_irq_restore(flags);
> > -	free_page((unsigned long)input_pg);
> > +
> > +	free_page((unsigned long)pg);
> >  
> 
> Hm, but in case we've allocated output_arg, don't we need to do
> 	free_pages((unsigned long)pg, 1);
> 
> instead?

Indeed. This has been fixed with:

    free_pages((unsigned long)pg, hv_root_partition ? 1 : 0);

Wei.