From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alex Williamson <alex.williamson@hp.com>
Subject: Re: [PATCH v3] kvm: Use a bitmap for tracking used GSIs
Date: Tue, 12 May 2009 22:10:34 -0600
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To: "Yang, Sheng" <sheng.yang@intel.com>
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On Tue, 2009-05-12 at 21:42 -0600, Alex Williamson wrote:
> On Wed, 2009-05-13 at 11:30 +0800, Yang, Sheng wrote:
> > > +	kvm->used_gsi_bitmap = malloc(gsi_bytes);
> > > +	if (!kvm->used_gsi_bitmap) {
> > > +		pthread_mutex_unlock(&kvm->gsi_mutex);
> > > +		goto out_close;
> > > +	}
> > > +	memset(kvm->used_gsi_bitmap, 0, gsi_bytes);
> > > +	kvm->max_gsi = gsi_bytes * 8;
> > 
> > So max_gsi = gsi_count / 4?

kvm->max_gsi actually becomes the number of GSIs available in the
bitmap, which may be more than gsi_count if we rounded up.  We
preallocate GSIs between gsi_count and max_gsi to avoid using them.
This just lets us not need to special case testing whether a bit in the
last index is < gsi_count.  Am I overlooking anything here?  Thanks,

Alex