[PATCH] arm64: KVM: Do not inject a 64bit fault for a 32bit guest

[Russell King - ARM Linux]

On Thu, Aug 27, 2015 at 03:05:47PM +0100, Marc Zyngier wrote:
> When injecting a fault into a 32bit guest, it seems rather idiotic
> to also inject a 64bit fault that is only going to corrupt the
> guest state, and lead to a situation where we restore an illegal
> context.
> 
> Just fix the stupid bug that has been there from day 1.
> 
> Cc: stable at vger.kernel.org
> Reported-by: Russell King <linux at arm.linux.org.uk>

s/linux/rmk+kernel/ please

Tested-by: Russell King <rmk+kernel at arm.linux.org.uk>

> Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
> ---
> Will: Paolo being on holiday, do you mind merging this one
> via your tree?

I don't think the commit message does this bug justice.  The implication
is it's just a guest issue.  It isn't, the bug appears to take out the
host kernel in a truely spectacular way.

http://www.arm.linux.org.uk/developer/build/result.php?type=boot&idx=4871

Tested here, the fix stops the host kernel exploding.  The crashed kvm
instance can be stopped and a proper kernel can then be booted in a new
guest instance.

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