Re: [Xen-devel] issue in unplug qemu PCI devices

[Edwin Zhai <edwin.zhai@xxxxxxxxx>]

Stefano,
Thanks for your fix. I'm in leave now and will have a test after back.
BTW, do you think we need fix issue 2? You know some OSV will install
and load the platform_pci module in guest by default. If end user
doesn't config valid PV device in config file, guest would crash after
unplugging emulated device. Is it necessary that we check if having a
valid backend in xenstore before unplug related emulated device?

Thanks,


On Sat, Feb 13, 2010 at 1:14 AM, Stefano Stabellini
<stefano.stabellini@xxxxxxxxxxxxx> wrote:
> On Fri, 12 Feb 2010, Zhai, Edwin wrote:
>> BTW, the unplug logic itself has some issues also:
>> 1. Pass-through NICs are also unplugged, although them have different
>> path with vnif and emulated NIC.
>> 2. Unplug happens as long as inserting the xen_platform_pci module
>> regardless of existence of PVed device in the config file. End user
>> likely to unplug all the PCI device by accident.
>> 3. Inserting xen_platform_pci module would unplug all the devices, which
>> is not reasonable. E.g. end user only has vbd driver, but all NICs are
>> also unplugged.
>>
>
> You are right, that is a bug and this patch should fix it.
>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
>
> ---
>
> diff --git a/hw/pci.c b/hw/pci.c
> index d7c516e..01eff8d 100644
> --- a/hw/pci.c
> +++ b/hw/pci.c
> @@ -826,7 +826,8 @@ void pci_unplug_netifs(void)
>            dev = bus->devices[x];
>            if (dev &&
>                dev->config[0xa] == 0 &&
> -               dev->config[0xb] == 2) {
> +               dev->config[0xb] == 2 &&
> +               test_pci_slot(x >> 3) != 1) {
>                /* Found a netif.  Remove it from the bus.  Note that
>                   we don't free it here, since there could still be
>                   references to it floating around.  There are only
>
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>



-- 
Best Rgds
Zhai Edwin

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