Re: [PATCH RFC 2/5] KVM: use a rapper function to calculate the sizes of dirty bitmaps

[Avi Kivity <avi@redhat.com>]

On 04/09/2010 12:32 PM, Takuya Yoshikawa wrote:
> We will use this later in other parts.
>
>    

s/rapper/wrapper/...

>
> +static inline int kvm_dirty_bitmap_bytes(struct kvm_memory_slot *memslot)
> +{
> +	return ALIGN(memslot->npages, BITS_PER_LONG) / 8;
> +}
> +
>    

'int' may overflow.

>   struct kvm_kernel_irq_routing_entry {
>   	u32 gsi;
>   	u32 type;
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 9379533..5ab581e 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -645,7 +645,7 @@ skip_lpage:
>
>   	/* Allocate page dirty bitmap if needed */
>   	if ((new.flags&  KVM_MEM_LOG_DIRTY_PAGES)&&  !new.dirty_bitmap) {
> -		unsigned dirty_bytes = ALIGN(npages, BITS_PER_LONG) / 8;
> +		int dirty_bytes = kvm_dirty_bitmap_bytes(&new);
>    

Ah, an existing bug.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.