Amazon AMIs

[Andriy Gapon]

On 28/05/2019 21:19, Colin Percival wrote:
> On 5/28/19 5:52 AM, Andriy Gapon wrote:
>> On 21/02/2019 18:17, Warner Losh wrote:
>>> It's hot-unplug that doesn't work quite right. Hotplug works, I believe, if
>>> you have PCI_HP in your kernel, I believe.
>>>
>>> What's needed is about a solid week of cleanup and testing in this area,
>>> however.
>>
>> I am not sure about the context of the latest question... whether it was about
>> NVMe hot-plug on real modern hardware or whether it was still about AWS.
>> In the latter case, as Colin pointed out earlier[*], PCI_HP would not help at
>> all, because the emulated bridge is not a PCIe bridge.
>> It seems that they use a mechanism based on an older specification, PCI Standard
>> Hot-Plug Controller and Subsystem Specification.
> 
> Right, these EC2 instances look like they have NVMe devices being hotplugged
> on a legacy PCI bus attached to an Intel 440FX chipset.  There is no real
> hardware which behaves the same way as these VMs.

I guess so, but I believe that it still conforms to the mentioned specification,
at least to a degree (google key words are SHPC+PCI).  But I must admit that I
haven't actually read it, just skimmed a couple of sections.
It looks like Linux has support for that kind of the hot-plug.

Just found some additional interesting details:
https://github.com/intel/nemu/wiki/ACPI-PCI-discovery-hotplug

-- 
Andriy Gapon