Re: [Qemu-devel] [PATCH 03/16] tlb_set_page_with_attrs: Take argument specifying AddressSpace to use

[Edgar E. Iglesias]

On Fri, Nov 06, 2015 at 02:49:05PM +0100, Edgar E. Iglesias wrote:
> On Fri, Nov 06, 2015 at 01:41:54PM +0000, Peter Maydell wrote:
> > On 6 November 2015 at 13:27, Edgar E. Iglesias <address@hidden> wrote:
> > > On Thu, Nov 05, 2015 at 06:15:45PM +0000, Peter Maydell wrote:
> > >> Add an argument to tlb_set_page_with_attrs which allows the target CPU 
> > >> code
> > >> to tell the core code which AddressSpace to use.
> > >>
> > >> The AddressSpace is specified by the index into the array of ASes which
> > >> were registered with cpu_address_space_init().
> > 
> > >> --- a/exec.c
> > >> +++ b/exec.c
> > >> @@ -445,12 +445,13 @@ MemoryRegion *address_space_translate(AddressSpace 
> > >> *as, hwaddr addr,
> > >>
> > >>  /* Called from RCU critical section */
> > >>  MemoryRegionSection *
> > >> -address_space_translate_for_iotlb(CPUState *cpu, hwaddr addr,
> > >> +address_space_translate_for_iotlb(CPUState *cpu, int asidx, hwaddr addr,
> > >>                                    hwaddr *xlat, hwaddr *plen)
> > >
> > > Does it make sense to replace the CPUState argument with an AddressSpace *
> > > and have the callers do the cpu->cpu_ases[asidx]?
> > > It would be more consistent and eventually maybe eliminate the need for
> > > address_space_translate_for_iotlb in favor of calling 
> > > address_space_translate
> > > directly?
> > 
> > We can't accept an arbitrary AddressSpace, it has to be one which is
> > embedded in a CPUAddressSpace and which we can thus find the
> > memory_dispatch for. So you could pass a CPUAddressSpace*, but not
> > an AddressSpace*. But to pass a CPUAddressSpace we would have to
> > expose the currently-private-to-exec.c layout of the CPUAddressSpace
> > struct. I chose not to do that (and you can see the results elsewhere
> > in the patch series, like the function that's basically just "do
> > the cs_ases array lookup for me"); there's an argument for making
> > the structure more widely available to avoid some of that.
> 
> Aha, I see.. Thanks for clarifying.
>

That was the only comment I had so:

Reviewed-by: Edgar E. Iglesias <address@hidden>