doc: walkthroughs/VM.start: Update the xenguest chapter (domain build)

[bernhardkaindl]

Update:

• No longer add the links to not "official" source repositories for xenguest.

Update and extend the walkthrough of VM.start:

• Update the links to xenopsd functions from xapi-project/xenopsd.git to the current xenopsd code in xapi-project/xen-api.git
• Add the step for storing the platform data (vCPUs, vCPU affinity, etc.) in the domain's Xenstore tree.xenguest then uses this in thebuild` phase to build the domain.
• Convert the paragraphs about xenguest into a dedicated chapter on xenguest.
• Add a summary of the data that xenopsd passes to xenguest for the domain build
• Add a summary of the steps that xenguest takes to build the domain.

[last-genius]

Great to see this, thank you very much!

[bernhardkaindl]

@robhoes: Done as suggested: Removed the links to not "offical" source repositories.

[bernhardkaindl]

This was a small update for improving the structure.
Update the chapter 3.1 title to:

3.1 Interface to xenguest for building domains

At then end of it, add a brief summary on the platform data passed to xenguest:

When called to build a domain, xenguest reads those and builds the VM accordingly.

Add a new chapter heading to describe what the content of the remaining lines:

3.2 Workflow for allocating and populating domain memory

[last-genius]

@robhoes Can we merge this?

[robhoes]

@last-genius I haven't reviewed the text myself, but if other have then I'm happy for this to get merged.

[bernhardkaindl]

Hi @last-genius and @psafont!

@robhoes wrote #6272 (comment) for merging this PR:

@last-genius I haven't reviewed the text myself, but if other have then I'm happy for this to get merged.

If you could kindly add a comment that you reviewed the text, @robhoes would be open for merging it.

For your review, please find a preview of the docs with this PR here:
https://bernhard-xapi-onrender-com-pr-7.onrender.com/xenopsd/walkthroughs/VM.start/index.html#2-create-a-xen-domain

~Bernhard

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PS:

How the preview was generated:

I configured a fork of this repository for automatic Hugo previews on http://render.com using this blueprint: https://github.com/bernhard-xapi/bernhard-xapi.onrender.com/blob/main/render.yaml. After enabling previews for pull requests , I got this preview site created automatically after opening a local PR in the repository. This is the PR showing the creation of the preview site: bernhard-xapi#7 (it only supports local pull requests within the repository, so I had to create a local PR for it)

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PPS:

I'm thankful that this small team created a documentation site that is accessible and well-maintained and helps newcomers to understand the miracles this software does.

I do think that this documentation is an great asset that is very helpful to understand how the individual parts work. For example, the Xen hypervisor does not have such a single integrated documentation site for all things Xen.

[last-genius]

I am happy with the docs, so merging it.