[Suggestion] arch: arm64: xen: "ln -s" the paravirt.h from arm.

Tue Jun 25 08:32:16 EDT 2013

On Tue, 25 Jun 2013, Chen Gang wrote:
> On 06/25/2013 12:50 AM, Stefano Stabellini wrote:
> > On Mon, 24 Jun 2013, Stefano Stabellini wrote:
> >> > On Mon, 24 Jun 2013, Chen Gang wrote:
> >>> > > Hello Maintainers:
> >>> > > 
> >>> > > if 'CONFIG_XEN'
> >>> > > 
> >>> > >   CC      arch/arm64/xen/../../arm/xen/enlighten.o
> >>> > > arch/arm64/xen/../../arm/xen/enlighten.c:19:26: fatal error: asm/paravirt.h: No such file or directory
> >>> > > 
> >>> > > The related .config file for next-20130624 is in attachment.
> >>> > > 
> >>> > > 
> >>> > > If "ln -s ../../../arm/include/asm/paravirt.h paravirt.h", it can pass
> >>> > > compiling, but I do not know how to make a patch for it ("ln -s ..."),
> >>> > > Do we have another more suitable ways for it (or another fixing ways) ?
> >>> > > 
> >>> > > Welcome any suggestions or completions.
> >> > 
> >> > The problem is caused by:
> >> > 
> >> > commit 3a885582a366caf868b0782041c44854ff4c3568
> >> > Author: Stefano Stabellini <stefano.stabellini at eu.citrix.com>
> >> > Date:   Wed May 29 10:56:34 2013 +0000
> >> > 
> >> >     xen/arm: account for stolen ticks
> >> > 
> >> > that is in my tree for linux-next (even though I have not received any
> >> > replies from the ARM maintainers so I don't know when and if it is going
> >> > to go upstream).
> >> > 
> >> > I think that the best thing to do would be to add a couple of ifdef
> >> > CONFIG_PARAVIRT in arch/arm/xen/enlighten.c. I'll add them to my tree.
> > Actually now that we have XEN support under arm64, we can just introduce the
> > same pv_time_op struct and paravirt header that this patch
> > 
> > http://marc.info/?l=linux-arm-kernel&m=136992435301890&w=2
> > 
> > is introducing under arm.
> > Any opinions?
> > 
> 
> OK, thanks, and excuse me, I can not open the link above (the reason
> maybe it can not be accessed from China).

Strange. If you know how to search for a Message-ID, this one is

1369920902-3546-3-git-send-email-stefano.stabellini at eu.citrix.com

> But at least, the patch below is better than "ln -s" (which I provided).

yeah :)

> > ---
> > 
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index 19c1cde..47bd26b 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -207,6 +207,25 @@ config FORCE_MAX_ZONEORDER
> >  	default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
> >  	default "11"
> >  
> > +config PARAVIRT
> > +	bool "Enable paravirtualization code"
> > +	---help---
> > +	  This changes the kernel so it can modify itself when it is run
> > +	  under a hypervisor, potentially improving performance significantly
> > +	  over full virtualization.
> > +
> > +config PARAVIRT_TIME_ACCOUNTING
> > +	bool "Paravirtual steal time accounting"
> > +	select PARAVIRT
> > +	default n
> > +	---help---
> > +	  Select this option to enable fine granularity task steal time
> > +	  accounting. Time spent executing other tasks in parallel with
> > +	  the current vCPU is discounted from the vCPU power. To account for
> > +	  that, there can be a small performance impact.
> > +
> > +	  If in doubt, say N here.
> > +
> >  config XEN_DOM0
> >  	def_bool y
> >  	depends on XEN
> > @@ -214,6 +233,7 @@ config XEN_DOM0
> >  config XEN
> >  	bool "Xen guest support on ARM64 (EXPERIMENTAL)"
> >  	depends on ARM64 && OF
> > +	select PARAVIRT
> >  	help
> >  	  Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
> >  
> > diff --git a/arch/arm64/include/asm/paravirt.h b/arch/arm64/include/asm/paravirt.h
> > new file mode 100644
> > index 0000000..54e895b
> > --- /dev/null
> > +++ b/arch/arm64/include/asm/paravirt.h
> > @@ -0,0 +1,19 @@
> > +#ifndef _ASM_ARM64_PARAVIRT_H
> > +#define _ASM_ARM64_PARAVIRT_H
> > +
> > +struct static_key;
> > +extern struct static_key paravirt_steal_enabled;
> > +extern struct static_key paravirt_steal_rq_enabled;
> > +
> > +struct pv_time_ops {
> > +	unsigned long long (*steal_clock)(int cpu);
> > +};
> > +extern struct pv_time_ops pv_time_ops;
> > +
> > +static inline u64 paravirt_steal_clock(int cpu)
> > +{
> > +	return pv_time_ops.steal_clock(cpu);
> > +}
> > +
> > +
> > +#endif
> > diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
> > index 7b4b564..17613ad 100644
> > --- a/arch/arm64/kernel/Makefile
> > +++ b/arch/arm64/kernel/Makefile
> > @@ -18,6 +18,7 @@ arm64-obj-$(CONFIG_SMP)			+= smp.o smp_spin_table.o smp_psci.o
> >  arm64-obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o
> >  arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)+= hw_breakpoint.o
> >  arm64-obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
> > +arm64-obj-$(CONFIG_PARAVIRT)		+= paravirt.o
> >  
> >  obj-y					+= $(arm64-obj-y) vdso/
> >  obj-m					+= $(arm64-obj-m)
> > diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c
> > new file mode 100644
> > index 0000000..53f371e
> > --- /dev/null
> > +++ b/arch/arm64/kernel/paravirt.c
> > @@ -0,0 +1,25 @@
> > +/*
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + *
> > + * Copyright (C) 2013 Citrix Systems
> > + *
> > + * Author: Stefano Stabellini <stefano.stabellini at eu.citrix.com>
> > + */
> > +
> > +#include <linux/export.h>
> > +#include <linux/jump_label.h>
> > +#include <linux/types.h>
> > +#include <asm/paravirt.h>
> > +
> > +struct static_key paravirt_steal_enabled;
> > +struct static_key paravirt_steal_rq_enabled;
> > +
> > +struct pv_time_ops pv_time_ops;
> > +EXPORT_SYMBOL_GPL(pv_time_ops);
> > 
> > 