Re: [PATCH v3 7/7] mm: allow page scrubbing routine(s) to be arch controlled

[Julien Grall <julien@xxxxxxx>]

Hi Jan,

On 26/11/2024 08:02, Jan Beulich wrote:
> On 25.11.2024 23:17, Julien Grall wrote:
> > > --- a/xen/arch/arm/include/asm/page.h
> > > +++ b/xen/arch/arm/include/asm/page.h
> > > @@ -144,6 +144,12 @@ extern size_t dcache_line_bytes;
> > >    
> > >    #define copy_page(dp, sp) memcpy(dp, sp, PAGE_SIZE)
> > >    
> > > +#define clear_page_hot  clear_page
> > > +#define clear_page_cold clear_page
> > > +
> > > +#define scrub_page_hot(page) memset(page, SCRUB_BYTE_PATTERN, PAGE_SIZE)
> > > +#define scrub_page_cold      scrub_page_hot
> > This block seems to be common between all the arch but x86. Should we
> > add an header in asm generic?
> I'd say that largely depends on the intentions of Arm, RISC-V, and PPC.
> Personally I've always found it odd that memset() / memcpy() are used for
> page clearing / copying. Surely there are better ways, and pretty certainly
> about every arch also has distinct means to efficiently do "hot" and "cold"
> clearing. Therefore keeping these #define-s in per-arch headers imo serves
> as a reminder that something wants doing about them.
Fair enough. For the code:

Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

Cheers,

--
Julien Grall