On 5/17/2025 5:35 AM, Sean Christopherson wrote:
> Assert that slots_lock is held in kvm_dirty_ring_reset() and add a comment
> to explain _why_ slots needs to be held for the duration of the reset.
>
> Link: https://lore.kernel.org/all/aCSns6Q5oTkdXUEe@google.com
> Suggested-by: James Houghton <jthoughton@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> virt/kvm/dirty_ring.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/virt/kvm/dirty_ring.c b/virt/kvm/dirty_ring.c
> index 54734025658a..1ba02a06378c 100644
> --- a/virt/kvm/dirty_ring.c
> +++ b/virt/kvm/dirty_ring.c
> @@ -122,6 +122,14 @@ int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring,
> unsigned long mask = 0;
> struct kvm_dirty_gfn *entry;
>
> + /*
> + * Ensure concurrent calls to KVM_RESET_DIRTY_RINGS are serialized,
> + * e.g. so that KVM fully resets all entries processed by a given call
It seems that "e.g." is not needed?
> + * before returning to userspace. Holding slots_lock also protects
> + * the various memslot accesses.
> + */
> + lockdep_assert_held(&kvm->slots_lock);
> +
> while (likely((*nr_entries_reset) < INT_MAX)) {
> if (signal_pending(current))
> return -EINTR;