Re: [RFC 06/16] KVM: Use GUP instead of copy_from/to_user() to access guest memory

From: Kirill A. Shutemov
Date: Tue Jun 02 2020 - 09:33:09 EST

On Mon, Jun 01, 2020 at 06:35:22PM +0200, Paolo Bonzini wrote:
> On 25/05/20 17:17, Kirill A. Shutemov wrote:
> >> Personally, I would've just added 'struct kvm' pointer to 'struct
> >> kvm_memory_slot' to be able to extract 'mem_protected' info when
> >> needed. This will make the patch much smaller.
> > Okay, can do.
> >
> > Other thing I tried is to have per-slot flag to indicate that it's
> > protected. But Sean pointed that it's all-or-nothing feature and having
> > the flag in the slot would be misleading.
> >
> Perhaps it would be misleading, but it's an optimization. Saving a
> pointer dereference can be worth it, also because there are some places
> where we just pass around a memslot and we don't have the struct kvm*.

Vitaly proposed to add struct kvm pointer into memslot. Do you object
against it?

Kirill A. Shutemov