lkml.org 
[lkml]   [2013]   [Mar]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] KVM: allow host header to be included even for !CONFIG_KVM
On Thu, Mar 21, 2013 at 05:02:15PM -0700, Kevin Hilman wrote:
> Gleb Natapov <gleb@redhat.com> writes:
>
> > On Thu, Mar 21, 2013 at 02:33:13PM -0500, Scott Wood wrote:
> >> On 03/21/2013 02:16:00 PM, Gleb Natapov wrote:
> >> >On Thu, Mar 21, 2013 at 01:42:34PM -0500, Scott Wood wrote:
> >> >> On 03/21/2013 09:27:14 AM, Kevin Hilman wrote:
> >> >> >Gleb Natapov <gleb@redhat.com> writes:
> >> >> >
> >> >> >> On Wed, Mar 20, 2013 at 06:58:41PM -0500, Scott Wood wrote:
> >> >> >>> Why can't the entirety kvm_host.h be included regardless of
> >> >> >>> CONFIG_KVM, just like most other feature-specific headers? Why
> >> >> >>> can't the if/else just go around the functions that you want to
> >> >> >stub
> >> >> >>> out for non-KVM builds?
> >> >> >>>
> >> >> >> Kevin,
> >> >> >>
> >> >> >> What compilation failure this patch fixes? I presume
> >> >something ARM
> >> >> >> related.
> >> >> >
> >> >> >Not specficially ARM related, but more context tracking related
> >> >since
> >> >> >kernel/context_tracking.c pulls in kvm_host.h, which attempts to
> >> >> >pull in
> >> >> ><asm/kvm*.h> which may not exist on some platforms.
> >> >> >
> >> >> >At least for ARM, KVM support was added in v3.9 so this patch can
> >> >> >probably be dropped since the non-KVM builds on ARM now work.
> >> >But any
> >> >> >platform without the <asm/kvm*.h> will still be broken when
> >> >trying to
> >> >> >build the context tracker.
> >> >>
> >> >> Maybe other platforms should get empty asm/kvm*.h files. Is there
> >> >> anything from those files that the linux/kvm*.h headers need to
> >> >> build?
> >> >>
> >> >arch things. kvm_vcpu_arch, kvm_arch_memory_slot, kvm_arch etc.
> >>
> >> Could define them as empty structs.
> >>
> > Isn't is simpler for kernel/context_tracking.c to define empty
> > __guest_enter()/__guest_exit() if !CONFIG_KVM.
>
> I proposed something like that in an earlier version but Frederic asked
> me to propose a fix to the KVM headers instead.
>
> Just in case fixing the context tracking subsystem is preferred,
> the patch below fixes the problem also.
>
The patch that broke PPC build was reverted. Frederic can you get the
patch below?

> Kevin
>
> >From f22995a262144d0d61705fa72134694d911283eb Mon Sep 17 00:00:00 2001
> From: Kevin Hilman <khilman@linaro.org>
> Date: Thu, 21 Mar 2013 16:57:14 -0700
> Subject: [PATCH] context_tracking: fix !CONFIG_KVM compile: add stub guest
> enter/exit
>
> When KVM is not enabled, or not available on a platform, the KVM
> headers should not be included. Instead, just define stub
> __guest_[enter|exit] functions.
>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Signed-off-by: Kevin Hilman <khilman@linaro.org>
> ---
> kernel/context_tracking.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
> index 65349f0..64b0f80 100644
> --- a/kernel/context_tracking.c
> +++ b/kernel/context_tracking.c
> @@ -15,12 +15,18 @@
> */
>
> #include <linux/context_tracking.h>
> -#include <linux/kvm_host.h>
> #include <linux/rcupdate.h>
> #include <linux/sched.h>
> #include <linux/hardirq.h>
> #include <linux/export.h>
>
> +#if IS_ENABLED(CONFIG_KVM)
> +#include <linux/kvm_host.h>
> +#else
> +#define __guest_enter()
> +#define __guest_exit()
> +#endif
> +
> DEFINE_PER_CPU(struct context_tracking, context_tracking) = {
> #ifdef CONFIG_CONTEXT_TRACKING_FORCE
> .active = true,
> --
> 1.8.2

--
Gleb.


\
 
 \ /
  Last update: 2013-03-24 12:01    [W:0.077 / U:0.124 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site