On Mon, Oct 30, 2023 at 5:53 PM David Matlack <dmatlack@xxxxxxxxxx> wrote:
>
> On 2023-10-27 11:21 AM, Sean Christopherson wrote:
> > From: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>
> >
> > Currently in mmu_notifier invalidate path, hva range is recorded and
> > then checked against by mmu_notifier_retry_hva() in the page fault
> > handling path. However, for the to be introduced private memory, a page
> ^^^^^^^^^^^^^^^^^^^^^^^^
>
> Is there a missing word here?
No but there could be missing hyphens ("for the to-be-introduced
private memory"); possibly a "soon" could help parsing and that is
what you were talking about?
> > if (likely(kvm->mmu_invalidate_in_progress == 1)) {
> > + kvm->mmu_invalidate_range_start = INVALID_GPA;
> > + kvm->mmu_invalidate_range_end = INVALID_GPA;
>
> I don't think this is incorrect, but I was a little suprised to see this
> here rather than in end() when mmu_invalidate_in_progress decrements to
> 0.
I think that would be incorrect on the very first start?
> > + }
> > +}
> > +
> > +void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end)
> > +{
> > + lockdep_assert_held_write(&kvm->mmu_lock);
>
> Does this compile/function on KVM architectures with
> !KVM_HAVE_MMU_RWLOCK?
Yes:
#define lockdep_assert_held_write(l) \
lockdep_assert(lockdep_is_held_type(l, 0))
where 0 is the lock-held type used by lock_acquire_exclusive. In turn
is what you get for a spinlock or mutex, in addition to a rwlock or
rwsem that is taken for write.
Instead, lockdep_assert_held() asserts that the lock is taken without
asserting a particular lock-held type.
> > @@ -834,6 +851,12 @@ void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start,
>
> Let's add a lockdep_assert_held_write(&kvm->mmu_lock) here too while
> we're at it?
Yes, good idea.
Paolo
