From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wei Wang2 <wei.wang2@amd.com>
Subject: Re: [PATCH 03 of 16] amd iommu: Add iommu emulation for
	hvm guest
Date: Thu, 15 Dec 2011 15:09:28 +0100
Message-ID: <201112151509.29366.wei.wang2@amd.com>
References: <patchbomb.1323876561@gran.amd.com>
	<ea52a2b93dffe708084f.1323876564@gran.amd.com>
	<20111215133555.GE4274@ocelot.phlegethon.org>
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To: Tim Deegan <tim@xen.org>
Cc: xen-devel@lists.xensource.com, keir@xen.org, JBeulich@suse.com
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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