Re: [PATCH 2/6] KVM: Assert slots_lock is held in __kvm_set_memory_region()

Sean Christopherson
2024-08-05T22:01:56Z

On Mon, Aug 05, 2024, Tao Su wrote:
> On Fri, Aug 02, 2024 at 01:49:59PM -0700, Sean Christopherson wrote:
> > Add a proper lockdep assertion in __kvm_set_memory_region() instead of
> > relying on a function comment. Opportunistically delete the entire
> > function comment as the API doesn't allocate memory or select a gfn,
> > and the "mostly for framebuffers" comment hasn't been true for a very long
> > time.
> >
> > Signed-off-by: Sean Christopherson <seanjc@google.com>
> > ---
> > virt/kvm/kvm_main.c | 10 ++--------
> > 1 file changed, 2 insertions(+), 8 deletions(-)
> >
> > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> > index 0557d663b69b..f202bdbfca9e 100644
> > --- a/virt/kvm/kvm_main.c
> > +++ b/virt/kvm/kvm_main.c
> > @@ -1973,14 +1973,6 @@ static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id,
> > return false;
> > }
> >
> > -/*
> > - * Allocate some memory and give it an address in the guest physical address
> > - * space.
> > - *
> > - * Discontiguous memory is allowed, mostly for framebuffers.
> > - *
> > - * Must be called holding kvm->slots_lock for write.
> > - */
> > int __kvm_set_memory_region(struct kvm *kvm,
> > const struct kvm_userspace_memory_region2 *mem)
> > {
> > @@ -1992,6 +1984,8 @@ int __kvm_set_memory_region(struct kvm *kvm,
> > int as_id, id;
> > int r;
> >
> > + lockdep_assert_held(&kvm->slots_lock);
>
> How about adding this lockdep assertion in __x86_set_memory_region() to replace
> this comment "/* Called with kvm->slots_lock held. */" as well?

Ya, will do, I didn't see that comment.

Thanks!