Re: [PATCH] Add a new PIIX option to control PCI hot unplugging of devices on non-root buses

[Ani Sinha]

+Julia who implemented https://patchwork.kernel.org/patch/11388881/


> On Apr 18, 2020, at 3:26 AM, Laine Stump <address@hidden> wrote:
> 
> On 4/17/20 12:35 PM, Ani Sinha wrote:
>> +Laine
>>> On Apr 17, 2020, at 9:39 PM, Michael S. Tsirkin <address@hidden> wrote:
>>> 
>>> Problem is, I think this is not something we can support with pcie or shpc.
>>> I'm reluctant to add features that only ACPI can support,
>>> we are trying to phase that out.
>> Hmm. I see. We use conventional PCI and hence was looking for providing this 
>> feature for conventional PCI only. Laine might be able to throw some lights 
>> as to feasibility of the in PCIE world.
> 
> Sorry, my knowledge doesn't go that low. If there's a qemu option I can 
> expose it in libvirt, but am by no means an expert of qemu internals or the 
> pci/pcie specs :-)
> 
> (BTW, I think in the past people have prevented enabling hot-unplug by 
> unprivileged users in Windows with some sort of a "system policy" in Windows. 
> (whatever that is - I don't use Windows, and have just heard this from others 
> when discussing the problem).
> 

My question to Julia is whether it is possible to disable just hot unplug but 
keep hot plugging for PCIE devices enabled using PCI_EXP_SLTCAP_HPC  or 
otherwise in Qemu?