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Date: Tue, 29 Sep 2009 10:54:50 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
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Subject: [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config
	breakage
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To: Avi Kivity <avi@redhat.com>
Cc: john cooper <john.cooper@third-harmonic.com>, john cooper <john.cooper@redhat.com>, Rusty Russell <rusty@rustcorp.com.au>, qemu-devel@nongnu.org, Vadim Rozenfeld <vrozenfe@redhat.com>, jens.axboe@oracle.com

On Tue, Sep 29, 2009 at 09:22:53AM +0200, Avi Kivity wrote:
> On 09/29/2009 08:58 AM, Michael S. Tsirkin wrote:
>> Using bar per feature we'll quickly run out of BARs.
>> We already use a BAR for MSI-X - let's add
>> ATA identity there?
>>    
> Mixing unrelated features will quickly cause confusion.

Note if we ever switch to 64 bit BARs, we'll only have 3 of these
available, so the ID would be using the last free one.
We can just as well plan ahead for when we'll add another feature?

I agree fixed offsets are messy though.  I previously proposed storing
the offset to the identity data in an i/o register. This will let each
implementation lay out this data in an optimal manner, without
confusion.

> -- 
> Do not meddle in the internals of kernels, for they are subtle and quick to panic.