Re: [Qemu-devel] Dangling change state handler while hot unplugging ahci adapter

[John Snow]

On 08/09/2016 01:16 PM, Ashijeet Acharya wrote:
> Hi again,
> I am still waiting for some guidance...Can I please get some help with this?
>
> Also.. I tried hotplugging an AHCI adapter but got the following error:
> Bus 'ahci.0' does not support hotplugging
>
> Steps I followed:
>
> 1. launch vm with ahci enabled
> 2. (qemu) drive_add 0 file=test.qcow2,cache=none,if=none,id=disk2,format=qcow2
> OK
> 3. (qemu) device_add ide-hd,bus=ahci.0,id=ahci-disk,drive=disk2
> Bus 'ahci.0' does not support hotplugging
>
> What am I doing wrong?
>
> Thanks
> Ashijeet

I think you are confusing hotplugging the AHCI adapter with hotplugging 
an IDE drive into an AHCI adapter.

IDE/ATA/PATA (A rose by any other name...) drives do not support 
hotplugging (hence "Bus 'ahci.0' does not support hotplugging").

SATA drives do in theory, but it hasn't been implemented yet.

That's probably a little more involved than a Bite Sized Task, but it's 
something that I'd be willing to review if you embarked upon such a task.

> On Sat, Aug 6, 2016 at 11:21 PM, Ashijeet Acharya
> <address@hidden> wrote:
> > Hi,
> >
> > I was working on a patch regarding a device lifecycle bitesize task
> > and I wanted to clear my queries about what the task is exactly.
> >
> > Do I need to create a new function ahci_unrealize() in the
> > hw/ide/ahci.c file which calls for qemu_del_vm_change_state_handler()
> > to free the handler at the time of ahci hot unplug.

Sounds about right. grep around for other instances of 
qemu_del_vm_change_state_handler and try to code by example.

> > Please tell me if I am on the right path and correct me if I am wrong.
> >
> > Thanks
> > Ashijeet

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—js