Re: [PULL 3/3] hw/loongarch: Modify flash block size to 256K

[Philippe Mathieu-Daudé]

On 19/7/24 10:18, Daniel P. Berrangé wrote:
> On Fri, Jul 19, 2024 at 10:12:20AM +0200, Philippe Mathieu-Daudé wrote:
> > On 19/7/24 04:26, Song Gao wrote:
> > > From: Xianglai Li <lixianglai@loongson.cn>
> > >
> > > loongarch added a common library for edk2 to
> > > parse flash base addresses through fdt.
> > > For compatibility with other architectures,
> > > the flash block size in qemu is now changed to 256k.
> > >
> > > Signed-off-by: Xianglai Li <lixianglai@loongson.cn>
> > > Reviewed-by: Song Gao <gaosong@loongson.cn>
> > > Message-Id: <20240624033319.999631-1-lixianglai@loongson.cn>
> > > Signed-off-by: Song Gao <gaosong@loongson.cn>
> > > ---
> > >    include/hw/loongarch/virt.h | 2 +-
> > >    1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/include/hw/loongarch/virt.h b/include/hw/loongarch/virt.h
> > > index 8fdfacf268..603c1cebdb 100644
> > > --- a/include/hw/loongarch/virt.h
> > > +++ b/include/hw/loongarch/virt.h
> > > @@ -20,7 +20,7 @@
> > >    #define VIRT_FWCFG_BASE         0x1e020000UL
> > >    #define VIRT_BIOS_BASE          0x1c000000UL
> > >    #define VIRT_BIOS_SIZE          (16 * MiB)
> > > -#define VIRT_FLASH_SECTOR_SIZE  (128 * KiB)
> > > +#define VIRT_FLASH_SECTOR_SIZE  (256 * KiB)
> >
> > Again, I believe this breaks machine migration. See the recent
> > example Daniel explained to me:
> > https://lore.kernel.org/qemu-devel/Zn6EQ39Q57KtmKPU@redhat.com/
>
> Yes, changing flash size breaks migration compat, but note that loongarch
> does not have any versioned machine types, so it has zero migration compat
> right now regardles of this change. IOW, now is the right time to make the
> change, before someone asks for versioned machines with loongarch.

Oh I see now, thanks for clarifying!

It would have been nice to mention that in the commit description,
but too late so I don't mind.

Regards,

Phil.