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

[Catalin Marinas <catalin.marinas@arm.com>]

On Mon, Jun 24, 2013 at 05:50:46PM +0100, 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@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.

I'm not sure whether I replied to your Xen pull request but the patches
have been merged into my 'upstream' branch on git.kernel.org and they'll
be going in for 3.11-rc1.

> 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

No need for "default n".

If you want, I can apply this patch on top (or send me another pull
request but don't rebase your original Xen branch which I merged).

-- 
Catalin