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Re: [Qemu-devel] [PATCHv2 1/8] Introduce deriver_name field to DeviceInf
From: |
Gleb Natapov |
Subject: |
Re: [Qemu-devel] [PATCHv2 1/8] Introduce deriver_name field to DeviceInfo structure. |
Date: |
Sat, 6 Nov 2010 13:53:56 +0200 |
On Sat, Nov 06, 2010 at 10:01:25AM +0100, Markus Armbruster wrote:
[skip]
> > Why should Seabios match against three (or even more) different type of
> > devices to detect ata interface? Why require Seabios changes when this
> > can be avoided (if new device that provide ata is added)? OpenBIOS also
> > supports qemu BTW (this is Open Firmware implementation for pc, you can
> > run and see what kind of device paths it generates).
>
> I think we've finally cut through the confusion caused by the
> unfortunate choice of driver_name for this new device attribute.
>
> The fact that you choose values of your driver_name in a way that is
> inspired by the syntactic conventions of IEEE 1275 is not its
> distinguishing characteristic. The values of existing member name are
> inspired by that as well. driver_name's distinguishing characteristic
> is its purpose: communication with SeaBIOS.
>
My understanding of this name in IEEE 1275 is that it specifies what
driver in FW handles a device.
> I'm fine with you choosing its values however it's convenient for that
> purpose, as long as you give it a name reflecting that purpose. What
> about fw_name and qdev_fw_name()?
>
I am not attached to the name. Can "alias" be used for that purpose?
>
> Next, I'm worried about overloading of method get_dev_path(). It's
> being used for a very specific purpose: savevm/loadvm.
>
This part of the patch is not completed yet. I intend to change the code
in savevm/loadvm to call qdev_get_dev_path() to get full device path
there.
> * It's currently defined only for PCI devices. Your PATCH 7/8 changes
> its value there, from DOMAIN:BUS:SLOT.FUNCTION to address@hidden
>
Old definition is buggy BTW. BUS part is controlled by a guest and may
be different from default value at destination.
> - The old value identifies the qdev. The new value does not
> (remember, we have a separate qdev per PCI function). Why is this
> okay?
>
No no. New value is address@hidden,FUNC. Spec says that if FUNC is zero it
can be omitted.
> - Is the value saved with the VM? If yes, this is an incompatible
> change.
Don't understand that remark.
>
> * You extend it for ISA and System bus (PATCH 5,6/8). How does this
> affect savevm?
>
We should ask savevm experts. As far as I can see it affects id
creation. As long as id is unique we should be OK. We may send more info
on migration after the patches.
--
Gleb.
- Re: [Qemu-devel] [PATCHv2 1/8] Introduce deriver_name field to DeviceInfo structure., Markus Armbruster, 2010/11/04
- Re: [Qemu-devel] [PATCHv2 1/8] Introduce deriver_name field to DeviceInfo structure., Gleb Natapov, 2010/11/04
- Re: [Qemu-devel] [PATCHv2 1/8] Introduce deriver_name field to DeviceInfo structure., Markus Armbruster, 2010/11/04
- Re: [Qemu-devel] [PATCHv2 1/8] Introduce deriver_name field to DeviceInfo structure., Gleb Natapov, 2010/11/04
- Re: [Qemu-devel] [PATCHv2 1/8] Introduce deriver_name field to DeviceInfo structure., Markus Armbruster, 2010/11/05
- Re: [Qemu-devel] [PATCHv2 1/8] Introduce deriver_name field to DeviceInfo structure., Gleb Natapov, 2010/11/05
- Re: [Qemu-devel] [PATCHv2 1/8] Introduce deriver_name field to DeviceInfo structure., Markus Armbruster, 2010/11/05
- Re: [Qemu-devel] [PATCHv2 1/8] Introduce deriver_name field to DeviceInfo structure., Gleb Natapov, 2010/11/05
- Re: [Qemu-devel] [PATCHv2 1/8] Introduce deriver_name field to DeviceInfo structure., Markus Armbruster, 2010/11/06
- Re: [Qemu-devel] [PATCHv2 1/8] Introduce deriver_name field to DeviceInfo structure.,
Gleb Natapov <=
- Re: [Qemu-devel] [PATCHv2 1/8] Introduce deriver_name field to DeviceInfo structure., Markus Armbruster, 2010/11/06