Re: [RFC PATCH v2 22/69] KVM: x86: Add vm_type to differentiate legacy VMs from protected VMs

[Xiaoyao Li]

On 7/14/2021 4:39 AM, Sean Christopherson wrote:
> On Tue, Jul 06, 2021, Paolo Bonzini wrote:
> > On 03/07/21 00:04, isaku.yamahata@xxxxxxxxx wrote:
> > >    struct kvm_arch {
> > > +	unsigned long vm_type;
> >
> > Also why not just int or u8?
>
> Heh, because kvm_dev_ioctl_create_vm() takes an "unsigned long" for the type and
> it felt wrong to store it as something else.  Storing it as a smaller field should
> be fine, I highly doubt we'll get to 256 types anytime soon :-)

It's the bit position. We can get only 8 types with u8 actually.

> I think kvm_x86_ops.is_vm_type_supported() should take the full size though.