Re: [PATCH v2 0/3] xen/arm: Add emulation of Debug Data Transfer Registers

[Ayan Kumar Halder <ayankuma@xxxxxxx>]

On 20/12/2023 09:43, Luca Fancellu wrote:
> > On 20 Dec 2023, at 09:29, Luca Fancellu <Luca.Fancellu@xxxxxxx> wrote:
> >
> > Hi Ayan,
Hi Luca,

Thanks for looking into this.

> > > On 18 Dec 2023, at 20:29, Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx> wrote:
> > >
> > > Hi,
> > >
> > > Refer 
> > > https://lore.kernel.org/all/alpine.DEB.2.22.394.2312071341540.1265976@ubuntu-linux-20-04-desktop/T/
> > > for the previous discussion on this issue.
> > >
> > > Also, the linux earlycon hvc driver has been fixed.
> > > See 
> > > https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git/commit/?h=tty-next&id=0ec058ece2f933aed66b76bd5cb9b5e6764853c3
> > >
> > > Changes from v1:-
> > > 1. Split the change across 3 patches as per the design consensus.
> > >
> > > Ayan Kumar Halder (3):
> > > xen/arm: Add emulation of Debug Data Transfer Registers
> > > xen: arm: Introduce CONFIG_PARTIAL_EMULATION
> > > xen/arm: Introduce "partial-emulation" xen command line option
> > I’m a bit puzzled about the order of these changes, wouldn’t be better to
> > Introduce the partial emulation Kconfig and command line args in the same
> > patch together with something that uses it?
You have read my mind. :) I wan't sure about how to do the split...

> > I think here you wanted to keep Michal patch untouched, but I feel that a
> > correct split for this serie would be maybe introducing Kconfig, boot args and
> > one of the arm64/arm32 emulation, and on a second patch the other one
> > (Or vice-versa)?
>   ^^^^^^^-----> for the vice-versa, I meant 1st patch Arm64, 2nd Arm32
>   or vice-versa.
I wanted to keep Michal's change for the arm64 as it is. And introduce 
Kconfig and command line in separate patches.
But I agree, it does not look clean.


I am fine to follow your suggestion ie (Option 1)

Patch 1 ---> arm64 changes + Kconfig + cmd_line (authored by Michal)

Patch 2 ---> arm32 changes (which will use the Kconfig and cmd_line 
introduced before)

Alternatively, I am thinking like this (Option 2)

Patch 1 --> arm64 changes (authored by Michal)

Patch 2 --> arm32 changes

Patch 3 ---> Kconfig + cmd_line (which will touch patch 1 and 2).

Let me know what you (+ Stefano, Julien, Bertrand) think about the split.

I don't have a strong preference on how the split should be done.


- Ayan

> > If there is something that I’m missing let me know.
> >
> > > docs/misc/xen-command-line.pandoc    |  7 +++++
> > > xen/arch/arm/Kconfig                 |  8 +++++
> > > xen/arch/arm/arm64/vsysreg.c         | 32 ++++++++++++++++---
> > > xen/arch/arm/include/asm/arm64/hsr.h |  3 ++
> > > xen/arch/arm/include/asm/cpregs.h    |  2 ++
> > > xen/arch/arm/include/asm/regs.h      |  6 ++++
> > > xen/arch/arm/include/asm/traps.h     |  4 +++
> > > xen/arch/arm/traps.c                 | 21 +++++++++++++
> > > xen/arch/arm/vcpreg.c                | 47 +++++++++++++++++++++++-----
> > > 9 files changed, 117 insertions(+), 13 deletions(-)
> > >
> > > --
> > > 2.25.1