Re: [RFC PATCH 0/2] Fix cross migration issue with missing features: pdcm, arch-capabilities

[Paolo Bonzini <pbonzini@redhat.com>]

On 9/10/25 13:57, Hector Cao wrote:
> Hello,
> 
> Since it is a blocking issue for us, we went further and ended up with a solution along [1]
> that allows us to get out of this situation.
> 
> The idea is to add compatibility properties to restore legacy behaviors for machine types
> with older versions of QEMU (<10.1). 2 compatiblity properties have been added to address
> respectively the 2 missing features, each one is done in a separate patch.
> 
> We know that 10.1 has been released and it's final, but working on a solution towards 11.0
> would allow everyone to settle on the fix and even consider backporting where not yet released
> like Ubuntu 25.10 for us.

Thanks, I have applied the patch.  It's better to have the fix in 10.1.1.

Sorry for the delay, I was on vacation for one week and working reduced 
hours the next.

Paolo

> It is important to have upstream support going forward in this or any other way
> and therefore reach out with this RFC to ask you to think about it with us.
> 
> [1] https://gitlab.com/qemu-project/qemu/-/blob/master/docs/devel/migration/compatibility.rst
> 
> Hector Cao (2):
>    target/i386: add compatibility property for arch_capabilities
>    target/i386: add compatibility property for pdcm feature
> 
>   hw/core/machine.c     |  2 ++
>   migration/migration.h | 23 +++++++++++++++++++++++
>   migration/options.c   |  6 ++++++
>   target/i386/cpu.c     | 17 ++++++++++++++---
>   target/i386/kvm/kvm.c |  5 ++++-
>   5 files changed, 49 insertions(+), 4 deletions(-)
>