Patchwork [17/17] KVM: PPC: MPIC: Restrict to e500 platforms

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Submitter Alexander Graf
Date April 18, 2013, 2:11 p.m.
Message ID <1366294317-25529-18-git-send-email-agraf@suse.de>
Download mbox | patch
Permalink /patch/237652/
State New
Headers show

Comments

Alexander Graf - April 18, 2013, 2:11 p.m.
The code as is doesn't make any sense on non-e500 platforms. Restrict it
there, so that people don't get wrong ideas on what would actually work.

This patch should get reverted as soon as it's possible to either run e500
guests on non-e500 hosts or the MPIC emulation gains support for non-e500
modes.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 arch/powerpc/kvm/Kconfig |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
Scott Wood - April 18, 2013, 2:29 p.m.
On 04/18/2013 09:11:57 AM, Alexander Graf wrote:
> The code as is doesn't make any sense on non-e500 platforms.

Why?  What actually breaks?

You never answered my earlier question about whether 74xx is  
supported.  MPC86xx is 74xx-derived and has an FSL MPIC.

Plus, as pointed out earlier, this limits allyesconfig build testing.

-Scott
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Alexander Graf - April 18, 2013, 2:52 p.m.
On 18.04.2013, at 16:29, Scott Wood wrote:

> On 04/18/2013 09:11:57 AM, Alexander Graf wrote:
>> The code as is doesn't make any sense on non-e500 platforms.
> 
> Why?  What actually breaks?

It broke even compiling, because book3s doesn't provide anything for EPR for example. I fixed up the issues I found, but it's clear that this is an untested configuration.

> You never answered my earlier question about whether 74xx is supported.  MPC86xx is 74xx-derived and has an FSL MPIC.

Heck, even get_current_cpu() has no chance of working on book3s as it is today. I would prefer that anyone who wants to run MPC86xx with in an-kernel MPIC (which is a pure optimization!) just sits down, enables it and reverts this patch.

> Plus, as pointed out earlier, this limits allyesconfig build testing.

That's the point. It's code that only ever got tested on e500.


Alex

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Patch

diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index a608570..e88b1da 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -153,7 +153,7 @@  config KVM_E500MC
 
 config KVM_MPIC
 	bool "KVM in-kernel MPIC emulation"
-	depends on KVM
+	depends on KVM && E500
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_IRQ_ROUTING
 	select HAVE_KVM_MSI