Re: [PATCH v2 1/2] xen/arm32: head: Rework how the fixmap and early UART mapping are prepared

[Julien Grall <julien@xxxxxxx>]

Hi Michal,

On 12/01/2024 07:46, Michal Orzel wrote:
> On 11/01/2024 19:34, Julien Grall wrote:
> > From: Julien Grall <jgrall@xxxxxxxxxx>
> >
> > Since commit 5e213f0f4d2c ("xen/arm32: head: Widen the use of the
> > temporary mapping"), boot_second (used to cover regions like Xen and
> > the fixmap) will not be mapped if the identity mapping overlap.
> >
> > So it is ok to prepare the fixmap table and link it in boot_second
> > earlier. With that, the fixmap can also be used earlier via the
> > temporary mapping.
> >
> > Therefore split setup_fixmap() in two:
> >      * The table is now linked in create_page_tables() because
> >        the boot page tables needs to be recreated for every CPU.
> >      * The early UART mapping is only added for the boot CPU0 as the
> >        fixmap table is not cleared when secondary CPUs boot.
> >
> > Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
> Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
Thanks.

> with below 2 adjustments:
I will address them on commit.

> > +         */
> > +        mov_w r0, EARLY_UART_VIRTUAL_ADDRESS
> > +        create_mapping_entry xen_fixmap, r0, r11, type=PT_DEV_L3
> Would you mind listing r11 in the Input section of a comment?
I have added:

r11: UART physical address

> ~Michal
--
Julien Grall