Re: [Qemu-devel] [RFC PATCH 0/9] ACPI memory hotplug

[Anthony Liguori]

On 04/19/2012 09:08 AM, Vasilis Liaskovitis wrote:
> This is a prototype for ACPI memory hotplug on x86_64 target. Based on some
> earlier work and comments from Gleb.
>
> Memslot devices are modeled with a new qemu command line
>
> "-memslot id=name,start=start_addr,size=sz,node=pxm"

Hi,

For 1.2, I'd really like to focus on refactoring the PC machine as described in 
this series:

https://github.com/aliguori/qemu/commits/qom-rebase.12

I'd like to represent the guest memory as a "DIMM" device.

In terms of this proposal, I would then expect that the i440fx device would have 
a num_dimms property that controlled how many link<DIMM>'s it had.  Hotplug 
would consist of creating a DIMM at run time and connecting it to the 
appropriate link.

One thing that's not clear to me is how the start/size fits in.  On bare metal, 
is this something that's calculated by the firmware during start up and then 
populated in ACPI?   Does it do something like take the largest possible DIMM 
size that it supports and fill out the table?

At any rate, I think we should focus on modeling this in QOM verses adding a new 
option and hacking at the existing memory init code.

Regards,

Anthony Liguori