Re: [RFC PATCH v2 2/4] KVM: x86: Add optional KVM_CAP_LIVE_MIGRATION and KVM_MIGRATE_CMD

["Jörg Rödel" <joro@8bytes.org>]

On Mon, Sep 07, 2026 at 02:53:05PM +0300, Tony Lindgren wrote:
> On Mon, Aug 31, 2026 at 10:13:02AM +0300, Tony Lindgren wrote:
> > --- a/include/uapi/linux/kvm.h
> > +++ b/include/uapi/linux/kvm.h
> > @@ -1670,4 +1673,23 @@ struct kvm_pre_fault_memory {
> >  	__u64 padding[5];
> >  };
> >  
> > +#define KVM_MIGRATE_SETUP		0
> > +#define KVM_MIGRATE_ITERATION		1
> > +#define KVM_MIGRATE_STOP_AND_COPY	2
> > +#define KVM_MIGRATE_ABORT		3
> > +#define KVM_MIGRATE_END			4
> > +
> > +struct kvm_transfer_buffer {
> > +	__u64 address;
> > +	__u32 size;
> > +	__u32 reserved;
> > +};
> > +
> > +struct kvm_migrate_cmd {
> > +	__u16 command;
> > +	__u16 flags;
> > +	__u32 reserved;
> > +	struct kvm_transfer_buffer buf;
> > +};
> 
> For the common flags, KVM_MIGRATE_CMD probably should have migration
> direction. Or maybe we could have KVM_EXPORT_CMD and KVM_IMPORT_CMD.

The direction is always the same over a single live migration session, right?
So it could be a setup flag, on the other hand having separate KVM_EXPORT_CMD
and KVM_IMPORT_CMD seems to be a cleaner ABI.


-Joerg