Re: [PATCH v11 12/12] xen/arm: add cache coloring support for Xen image

[Julien Grall <julien@xxxxxxx>]

On 03/12/2024 10:08, Carlo Nonato wrote:
> Hi Julien,
>
> On Mon, Dec 2, 2024 at 10:44 PM Julien Grall <julien@xxxxxxx> wrote:
> > Hi Carlo,
> [...]
>
> > > diff --git a/xen/arch/arm/arm64/mmu/mm.c b/xen/arch/arm/arm64/mmu/mm.c
> > > index 671eaadbc1..3732d5897e 100644
> > > --- a/xen/arch/arm/arm64/mmu/mm.c
> > > +++ b/xen/arch/arm/arm64/mmu/mm.c
> > > @@ -1,6 +1,7 @@
> > >    /* SPDX-License-Identifier: GPL-2.0-only */
> > >
> > >    #include <xen/init.h>
> > > +#include <xen/llc-coloring.h>
> > >    #include <xen/mm.h>
> > >    #include <xen/pfn.h>
> > >
> > > @@ -138,27 +139,46 @@ void update_boot_mapping(bool enable)
> > >    }
> > >
> > >    extern void switch_ttbr_id(uint64_t ttbr);
> > > +extern void relocate_xen(uint64_t ttbr, void *src, void *dst, size_t len);
> > >
> > >    typedef void (switch_ttbr_fn)(uint64_t ttbr);
> > > +typedef void (relocate_xen_fn)(uint64_t ttbr, void *src, void *dst, size_t 
> > > len);
> > >
> > >    void __init switch_ttbr(uint64_t ttbr)
> > Given the change below, I think this function needs to be renamed.
> > Possibly to relocate_and_jump() with a comment explaning that the
> > relocation only happen for cache-coloring.
> Changing the name of switch_ttbr() to relocate_and_jump() seems a bit
> misleading to me. First I need to change the name also for arm32 where there's
> no relocation at all. Second, relocation is something that happens
> conditionally so I don't think it's a good name for the function.
Feel free to propose a new name. The main thing is the current name 
can't stay "switch_ttbr()" because you are doing more than switching the
TTBR.

The other solution is to have a separate call for relocating xen (which 
will fall-through to switch_ttbr) and another one for those that only to 
switch TTBR.
Cheers,

--
Julien Grall