Re: [RFC PATCH v2 3/4] KVM: x86: Add optional KVM_EXPORT_MEMORY and KVM_IMPORT_MEMORY

[Tony Lindgren <tony.lindgren@linux.intel.com>]

On Mon, Aug 31, 2026 at 07:23:47AM +0000, sashiko-bot@kernel.org wrote:
> commit b6f49e80a58eebaaa2a6d123950fd36709972a10
> Author: Tony Lindgren <tony.lindgren@linux.intel.com>
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> [ ... ]
> > @@ -7258,6 +7258,37 @@ long kvm_arch_vcpu_unlocked_ioctl(struct file *filp, unsigned int ioctl,
> >  	return -ENOIOCTLCMD;
> >  }
> >  
> > +static int kvm_vm_ioctl_transfer_memory(struct kvm *kvm, bool import,
> > +					void __user *argp)
> > +{
> > +	struct kvm_memory_transfer mem;
> > +	int r;
> > +
> > +	if (!kvm_x86_call(cap_live_migration)(kvm) ||
> > +	    (import && !kvm_x86_ops.import_memory) ||
> > +	    (!import && !kvm_x86_ops.export_memory))
> > +		return -ENOTTY;
> > +
> > +	if (copy_from_user(&mem, argp, sizeof(mem)))
> > +		return -EFAULT;
> > +
> > +	if (mem.reserved || mem.buf.reserved || !mem.nr_gfns)
> > +		return -EINVAL;
> 
> [Severity: Medium]
> Does this input validation for the kvm_memory_transfer UAPI struct miss
> checking mem.flags == 0 and mem.id == 0?

Yes flags is unused for memory transfers at least for TDX. The id TDX can
eventually use for the thread index for QEMU multifd transfers.