Re: [PATCH v6 27/29] KVM: Optimize overlapping memslots check

[Sean Christopherson]

On Tue, Nov 30, 2021, Maciej S. Szmigiero wrote:
> From: "Maciej S. Szmigiero" <maciej.szmigiero@xxxxxxxxxx>
> 
> Do a quick lookup for possibly overlapping gfns when creating or moving
> a memslot instead of performing a linear scan of the whole memslot set.
> 
> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@xxxxxxxxxx>
> [sean: tweaked params to avoid churn in future cleanup]
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> ---
>  virt/kvm/kvm_main.c | 35 +++++++++++++++++++++--------------
>  1 file changed, 21 insertions(+), 14 deletions(-)
> 
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 086f18969bc3..52117f65bc5b 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -1817,6 +1817,18 @@ static int kvm_set_memslot(struct kvm *kvm,
>  	return 0;
>  }
>  
> +static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id,
> +				      gfn_t start, gfn_t end)
> +{
> +	struct kvm_memslot_iter iter;
> +
> +	kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end)

The for loop needs curly braces, per coding-style.rst:

Also, use braces when a loop contains more than a single simple statement:

.. code-block:: c

        while (condition) {
                if (test)
                        do_something();
        }

With that,

Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>