Re: [SeaBIOS PATCH v3] hotplug: Add device per func in ACPI DSDT tables

[Amos Kong <akong@redhat.com>]

On 14/12/11 09:06, Kevin O'Connor wrote:
> On Tue, Dec 06, 2011 at 07:32:55PM -0500, Amos Kong wrote:
>> ----- Original Message -----
>>> On Tue, Dec 06, 2011 at 01:39:35PM +0800, Amos Kong wrote:
>>>> Only func 0 is registered to guest driver (we can
>>>> only found func 0 in slot->funcs list of driver),
>>>> the other functions could not be cleaned when
>>>> hot-removing the whole slot. This patch adds
>>>> device per function in ACPI DSDT tables.
>>>> Notify only when func0 is added and removed.
>>>>
>>>> Have tested with linux/winxp/win7, hot-adding/hot-remving,
>>>> single/multiple function device, they are all fine(all
>>>> added devices can be removed).
>>>>
>>> This includes some bits I wrote but this is not an ack
>>> of the patch yet :)
>>>
>>> I find it surprising that this works: a function
>>> has _EJ0 so would not guest expect that ejecting
>>> a single one will only remove it, and not all functions?
>>
>> Removing single func is not supported by specific, and current code
>> (qemu/kernel pci driver) process hot-remove with the whole slot.
>> We could not hot-remove single func with/without this patch.
>>
>> Register _EJ0() for each func, then all the funcs will be record
>> into the function list of the slot.
>
> Just as an update - it's not clear to me what this patch does, and it
> seems like Michael had some concerns.
>
> Also, it doesn't seem right to hardcode the generation of that many
> devices (248) in the AML code.

Hi Kevin,

When we hot-unplug a pci device, all functions in same slot should be 
unpluged
in one time. Hot-plug/unpluging nics for winXp VM is fine(all funcs can 
be removed).
But hot-unpluging nics of linux VM exists problem(only function 0 is 
removed),
Because not all the functions are registered in slot->funcs list in 
guest kernel.

What we can do to resolve this problem:

1. remove all the functions when hot-unplug one function in the slot
    http://marc.info/?l=kvm&m=131597620101566&w=2
    [PATCH] pci: clean all funcs when hot-removing multifunc device

2. register all the functions to slot->funcs list, then we don't need to
    change guest pci driver.
    http://marc.info/?l=kvm&m=132314964618843&w=2
    [SeaBIOS PATCH v3] hotplug: Add device per func in ACPI DSDT tables

mst, any more comment?

Thanks,
Amos

> So, unless there are further comments I'm going to hold off on this
> patch.
>
> -Kevin
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