Re: [PATCH] arm/docs: Drop mentioning of ACPI for properties under "hypervisor" node

[Oleksandr <olekstysh@xxxxxxxxx>]

On 10.12.21 11:00, Julien Grall wrote:
> Hi Oleksandr,

Hi Julien


> On 09/12/2021 20:50, Oleksandr Tyshchenko wrote:
> > From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> >
> > Remove the following sentence:
> > "This property is unnecessary when booting Dom0 using ACPI."
> > for "reg" and "interrupts" properties as the initialization is not
> > done via device-tree "hypervisor" node in that case anyway.
> Why do you think that? On ACPI, the hypervisor node is used to 
> discover whether the OS is running on top of Xen (see [1]).
> For dom0, Xen will actually create the hypervisor node with the 
> compatible property and the uefi bits (see [2]).
> The properties "regs" and "interrupts" are not created for ACPI and 
> therefore this should be mentioned in the Device-Tree bindings.

You are right. I missed that fact. Current patch is not needed in this case.


> > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> > ---
> >   docs/misc/arm/device-tree/guest.txt | 2 --
> >   1 file changed, 2 deletions(-)
> >
> > diff --git a/docs/misc/arm/device-tree/guest.txt 
> > b/docs/misc/arm/device-tree/guest.txt
> > index c115751..2b974bb 100644
> > --- a/docs/misc/arm/device-tree/guest.txt
> > +++ b/docs/misc/arm/device-tree/guest.txt
> > @@ -15,11 +15,9 @@ the following properties:
> >     or equal to gnttab_max_grant_frames()).
> >     Regions 1...N are extended regions (unused address space) for 
> > mapping foreign
> >     GFNs and grants, they might be absent if there is nothing to expose.
> > -  This property is unnecessary when booting Dom0 using ACPI.
> >     - interrupts: the interrupt used by Xen to inject event 
> > notifications.
> >     A GIC node is also required.
> > -  This property is unnecessary when booting Dom0 using ACPI.
> >     To support UEFI on Xen ARM virtual platforms, Xen populates the 
> > FDT "uefi" node
> >   under /hypervisor with following parameters:
> Cheers,
>
> [1] 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/xen/enlighten.c#n253
> [2] 
> https://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=xen/arch/arm/acpi/domain_build.c;h=bbdc90f92c003c0c6d0f0b0290a1776336224719;hb=HEAD#l90
--
Regards,

Oleksandr Tyshchenko