On Thu, May 16, 2024 at 9:51 PM Fiona Ebner <f.eb...@proxmox.com> wrote:
>
> Hi,
>
> Am 08.09.23 um 08:44 schrieb Jason Wang:
> > diff --git a/hw/core/machine.c b/hw/core/machine.c
> > index da699cf..230aab8 100644
> > --- a/hw/core/machine.c
> > +++ b/hw/core/machine.c
> > @@ -38,6 +38,7 @@
> > #include "exec/confidential-guest-support.h"
> > #include "hw/virtio/virtio.h"
> > #include "hw/virtio/virtio-pci.h"
> > +#include "hw/virtio/virtio-net.h"
> >
> > GlobalProperty hw_compat_8_1[] = {};
> > const size_t hw_compat_8_1_len = G_N_ELEMENTS(hw_compat_8_1);
> > @@ -45,6 +46,9 @@ const size_t hw_compat_8_1_len =
> > G_N_ELEMENTS(hw_compat_8_1);
> > GlobalProperty hw_compat_8_0[] = {
> > { "migration", "multifd-flush-after-each-section", "on"},
> > { TYPE_PCI_DEVICE, "x-pcie-ari-nextfn-1", "on" },
> > + { TYPE_VIRTIO_NET, "host_uso", "off"},
> > + { TYPE_VIRTIO_NET, "guest_uso4", "off"},
> > + { TYPE_VIRTIO_NET, "guest_uso6", "off"},
> > };
> > const size_t hw_compat_8_0_len = G_N_ELEMENTS(hw_compat_8_0);
> >
>
> unfortunately, this broke backwards migration with machine version 8.1
> from 8.2 and 9.0 binaries to a 8.1 binary:
>
> > kvm: Features 0x1c0010130afffa7 unsupported. Allowed features: 0x10179bfffe7
> > kvm: Failed to load virtio-net:virtio
> > kvm: error while loading state for instance 0x0 of device
> > '0000:00:12.0/virtio-net'
> > kvm: load of migration failed: Operation not permitted
>
> Since the series here only landed in 8.2, shouldn't these flags have
> been added to hw_compat_8_1[] instead?
You are right. We need to put them into hw_compat_8_1[].
>
> Attempting to fix it by moving the flags will break migration with
> machine version 8.1 between patched 9.0 and unpatched 9.0 however :(
I'm sorry but I can't think of a way better.
>
> Is there anything that can be done or will it need to stay broken now?
Would you mind posting a patch to fix this and cc stable?
>
> CC-ing the migration maintainers.
>
> Best Regards,
> Fiona
>
Thanks
