Re: [Qemu-devel] [Qemu-ppc] [PATCH 2/2] tcg/ppc*: Move cache initialization to ppc specific code

[Scott Wood]

On 10/03/2011 05:06 PM, Alexander Graf wrote:
> 
> On 03.10.2011, at 23:50, Scott Wood wrote:
> 
>> On 10/03/2011 04:36 PM, Alexander Graf wrote:
>>> With TCG, we're never executing guest code directly, but always go
>>> through TCG to emulate it. So the only case where we actually need to
>>> flush the icache is in TCG code generation, never outside, right?
>>
>> Right.
>>
>>> For KVM, I agree. We need some indication to flush the cache. But it
>>> doesn't have to be done that complicated. We can simply do an inline
>>> function that gets always called and has a few conditionals on when
>>> to actually flush. That inline function could easily be a nop on
>>> !ppc, though I'm not 100% sure that no other arch needs this.
>>
>> It's already an inline function that's a nop on !ppc.  What
>> simplification do you suggest?
> 
> Is flush_icache_range() always defined on all hosts with all compiler
> variants that QEMU supports? If not, we should have a small wrapper
> that explicitly makes it a nop on !ppc. CC'ing Paolo and Richard for
> clarification.

It's defined in cache-utils.h using GCC-style inline asm, and is a no-op
if _ARCH_PPC is not defined.

-Scott