Re: [PATCH v7 13/14] KVM: Enable and expose KVM_MEM_PRIVATE

[Chao Peng]

On Tue, Jul 19, 2022 at 11:55:24AM +0200, Gupta, Pankaj wrote:

...

> > @@ -4712,12 +4813,10 @@ static long kvm_vm_ioctl(struct file *filp,
> >                     (u32 __user *)(argp + offsetof(typeof(mem), flags))))
> >                     goto out;
> > -           if (flags & KVM_MEM_PRIVATE) {
> > -                   r = -EINVAL;
> > -                   goto out;
> > -           }
> > -
> > -           size = sizeof(struct kvm_userspace_memory_region);
> > +           if (flags & KVM_MEM_PRIVATE)
> > +                   size = sizeof(struct kvm_userspace_memory_region_ext);
> 
> Not sure if we use kvm_userspace_memory_region_ext or kvm_user_mem_region,
> just for readability.

Somehow, but majorly for code maintainability, kvm_user_mem_region is
designed to be the alias of kvm_userspace_memory_region_ext so in the
code we can access the 'unpacked' fields using something like
'mem.usersapce_addr' instead of 'mem.region.userspace_addr'.

Chao
> 
> > +           else
> > +                   size = sizeof(struct kvm_userspace_memory_region);
> >             if (copy_from_user(&mem, argp, size))
> >                     goto out;