Re: [Qemu-devel] [PATCH V16 1/4] docs: vm generation id device's description

[Eric Blake]

On 06/16/2015 08:11 AM, Gal Hammer wrote:
> Signed-off-by: Gal Hammer <address@hidden>
> ---
>  docs/specs/vmgenid.txt | 33 +++++++++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
>  create mode 100644 docs/specs/vmgenid.txt
> 
> diff --git a/docs/specs/vmgenid.txt b/docs/specs/vmgenid.txt
> new file mode 100644
> index 0000000..d06977a
> --- /dev/null
> +++ b/docs/specs/vmgenid.txt
> @@ -0,0 +1,33 @@
> +VIRTUAL MACHINE GENERATION ID
> +=============================
> +
> +Copyright (C) 2015 Red Hat, Inc.
> +
> +This work is licensed under the terms of the GNU GPL, version 2 or later.
> +See the COPYING file in the top-level directory.
> +
> +===
> +
> +The VM generation ID (vmgenid) device is an emulated device which
> +is expected to exposes a 128-bit, cryptographically random, integer value

s/exposes/expose/

> +identifier, provided by a management system (It is NOT in the device's
> +responsibilty to ensure that the value is cryptographically random).

s/responsibilty/responsibility/

> +
> +This allows management applications (e.g. libvirt) to notify the guest
> +operating system when the virtual machine is executed with a different
> +configuration (e.g. snapshot execution or creation from a template).
> +
> +This is specified on the web at: 
> http://go.microsoft.com/fwlink/?LinkId=260709
> +

Hopefully the link doesn't go stale too soon (when the cover page states
the same address, and the disclaimer "Information ... in this document,
URL and other Internet website references, may change without notice").
 On the other hand, the document is fairly loosely licensed ("You may
copy and use this document for your internal, reference purposes") even
if done in a non-free .docx format.  Do we need to hedge our bets and
save a copy of it in the qemu wiki?

> +---
> +
> +The vmgenid device is a device with the following ACPI ID: "QEMU0002".
> +
> +It has two properties:
> +
> +uuid - The virtual machine generation ID (A required UUID string)
> +addr - The uuid memory location (A 64-bit address, defaults to 0xfedf0000)
> +
> +According to the specification, any change to the GUID executes an
> +ACPI notification. The vmgenid device triggers the GPE._E00 which
> +executes the ACPI Notify operation.

Still would be nice for this document to contain sample QMP commands for
getting at the QOM object necessary for changing the id exposed to the
guest via this device (that is, not only talk about how the device is
implemented in the ACPI view of the guest, but also how the device is
managed from the application driving qemu).

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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