Re: [Xen-devel] [PATCH 03 of 16] amd iommu: Add iommu emulation for hvm guest

[Wei Wang2 <wei.wang2@xxxxxxx>]

On Thursday 15 December 2011 14:35:55 Tim Deegan wrote:
> Hi,
>
> At 16:29 +0100 on 14 Dec (1323880164), Wei Wang wrote:
> > +static struct page_info* guest_iommu_get_page(struct list_head *pglist,
> > +                                              unsigned int entry_size,
> > +                                              unsigned int pos)
> > +{
> > +    int idx;
> > +    struct list_head *head;
> > +    struct guest_pages *gpage = NULL;
> > +
> > +    idx = (pos * entry_size) >> PAGE_SHIFT;
> > +    list_for_each( head, pglist )
> > +    {
> > +        gpage = list_entry(head, struct guest_pages, list);
> > +        if ( (--idx) < 0 )
> > +            break;
> > +    }
>
> Given that you allocate all these elements together, and free them, all
> together, why not just use an array instead of a linked list?
>
> Cheers,
>
> Tim.
The numbers of element might be variant. But array should also work, 
considering iommu tables has max. length of 2MB, the array length is small.

Thanks,
Wei


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