Add support for GPT partition schema

[terryzbai]

The changes in block virtualiser check if the first sector is a Protective MBR in a GPT disk, and then accordingly initialise the disk. The main workflow is:

The changes in the block virtualiser check If the first sector is a Protective MBR sector, then request the following blocks containing partition table (block 1 to 4 in most cases) and the last blocks containing backup partition header and table (block -5 to -1 in most cases). After receiving all requested blocks, validate the partition header and table as well as backup partition header and table, and check if two partition headers match.

The script mkvirtdisk creates a MBR or GPT disk according to the last parameter.

[Ivan-Velickovic]

If you do git commit --amend -s and then git push -f it should fix the DCO check.

[midnightveil]

Would it be possible to either cherry pick this commit into this branch or merge it in first? This separates the functionality of reading the MBR from the main virtualiser logic (something more necessary for hotplugging) but also makes PRs like this less invasive (as most of this code really isn't core to the virtualiser).

[terryzbai]

Would it be possible to either cherry pick this commit into this branch or merge it in first? This separates the functionality of reading the MBR from the main virtualiser logic (something more necessary for hotplugging) but also makes PRs like this less invasive (as most of this code really isn't core to the virtualiser).

Done. Would you like to test it with your hotplugging features?

[midnightveil]

Done. Would you like to test it with your hotplugging features?

That might take a few days (I'm busy with end of term assignments), and most of this shouldn't affect hotplugging itself — it was 90% just moving to another file. So nah, not a blocker, and if there's issues with hotplugging I can resolve them later in the hotplugging PR.