Virtio net

[jounathaen]

This is a rebase and rework of #536 done by @BaderSZ

Original description:

This a somewhat-functional implementation for virtio-net. I'll follow up with comments, tests and likely a few examples for RustyHermit soon.

Fixes: #1
Fixes: #1162
Fixes: #253

Unsolved/for follow-up issues/prs:

• Mac Address generation is not implemented yet -> Network: Implement Mac Address generation #1333
• memory barriers: Use appropriate memory barriers for virtq accesses #1234
• MTU is hardcoded. -> Network: Adapt MTU to what the interface permits #1334

[codecov]

Codecov Report

❌ Patch coverage is 83.40381% with 157 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.80%. Comparing base (d7d66d0) to head (e37f7c2).
⚠️ Report is 9 commits behind head on main.

Files with missing lines	Patch %	Lines
src/virtio/net.rs	82.40%	79 Missing ⚠️
src/pci.rs	68.42%	30 Missing ⚠️
src/params.rs	4.34%	22 Missing ⚠️
src/linux/x86_64/kvm_cpu.rs	87.27%	7 Missing ⚠️
src/virtio/pci.rs	84.61%	6 Missing ⚠️
src/linux/x86_64/virtio_device.rs	94.87%	4 Missing ⚠️
src/net/tap.rs	94.80%	4 Missing ⚠️
src/vm.rs	85.00%	3 Missing ⚠️
src/bin/uhyve.rs	50.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #643      +/-   ##
==========================================
+ Coverage   76.39%   81.80%   +5.40%     
==========================================
  Files          29       33       +4     
  Lines        4266     4874     +608     
==========================================
+ Hits         3259     3987     +728     
+ Misses       1007      887     -120     

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[jounathaen]

If I get it right, using virtio-queue basically forces us to use virtio-mem as memory backend. (makes #645 obsolete).

[BaderSZ]

Some bugs were found when it comes to handling BARs: size/mode aren't handled correctly. I'll document progress and fix on BaderSZ#2

I believe all comments are sufficiently addressed now.

[jounathaen]

FINALLY!