From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH] Use PCI revision field to indicate virtio PCI ABI version Date: Tue, 29 Jan 2008 08:16:08 -0600 Message-ID: <479F3528.9040203@us.ibm.com> References: <1201535999-13998-1-git-send-email-aliguori@us.ibm.com> <200801291421.00278.rusty@rustcorp.com.au> <479EDDCE.8000000@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <479EDDCE.8000000@qumranet.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Avi Kivity Cc: virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org Avi Kivity wrote: > Rusty Russell wrote: >> On Tuesday 29 January 2008 02:59:59 Anthony Liguori wrote: >> >>> As Avi pointed out, as we continue to massage the virtio PCI ABI, we >>> can >>> make things a little more friendly to users by utilizing the PCI >>> revision >>> field to indicate which version of the ABI we're using. This is a >>> hard ABI >>> version and incrementing it will cause the guest driver to break. >>> >>> This is the necessary changes to virtio_pci to support this. >>> >>> Signed-off-by: Anthony Liguori >>> >> >> Applied, thanks. >> >> > > But that's done at the wrong level. Anthony agreed the revision ID > should indicate the device ABI, not just the virtio ABI. If we move > to that level, bumping just one device rev id on the host will break > all devices on the guest. That's not what I was agreeing too. I don't want to plumb an ABI interface through virtio for each device. This is what I didn't like about having an ABI field in the first place. I'm thinking we should just drop both of these and instead just rely on feature bits. Regards, Anthony Liguori