2013-04-19 18:07:23

by Sebastian Gottschall

Subject: arm: ARM_VIRT_EXT is not supported by all v7 platforms, so it should not be enabled by default

introduced in kernel 3.9 CONFIG_ARM_VIRT_EXT is default for all V7 arm
cpu's. this is wrong and breaks smp support on BCM4708 for example.
so keep it optional since no all v7 cpu's seem to support it. BCM4708
for instance is a arm cortex-a9. please merge this into one of the next
patches.


Index: arch/arm/mm/Kconfig
===================================================================
--- arch/arm/mm/Kconfig (revision 21211)
+++ arch/arm/mm/Kconfig (working copy)
@@ -640,8 +640,7 @@

config ARM_VIRT_EXT
bool
- depends on MMU
- default y if CPU_V7
+ depends on MMU && CPU_V7
help
Enable the kernel to make use of the ARM Virtualization
Extensions to install hypervisors without run-time firmware

2013-04-22 10:47:05

by Will Deacon

Subject: Re: arm: ARM_VIRT_EXT is not supported by all v7 platforms, so it should not be enabled by default

On Fri, Apr 19, 2013 at 07:07:15PM +0100, Sebastian Gottschall wrote:
> introduced in kernel 3.9 CONFIG_ARM_VIRT_EXT is default for all V7 arm
> cpu's. this is wrong and breaks smp support on BCM4708 for example.
> so keep it optional since no all v7 cpu's seem to support it. BCM4708
> for instance is a arm cortex-a9. please merge this into one of the next
> patches.

This was intentional, since ARM_VIRT_EXT shouldn't have any visible effect
when selected on CPUs without the virtualisation extensions.

If this is breaking SMP support, then there is a bug somewhere, so please
can elaborate on the problems which you are seeing?

Cheers,

Will