Uhyve Interface V2

[jounathaen]

The old uhyve interface is based on the outb instruction (on x86_64). This creates issues, when the physical memory of the guest is beyond the 32-Bit boundary, as the outb instruction only accepts 32-bit parameters.

I think the best approach is to move to MMIO based hypercalls instead (as also suggested in the KVM docu). Drawback: They are slower than IO based hypercalls.

Whilst on it, I redefined the hypercall interface and added the definition for possible future hypercalls.

Summary:

• Adding serial read hypercalls.
• Adding shared memory hypercalls
• removing the cmdline/environment hypercalls (this should be a boot parameter instead: Added command line and environment to the hermit entry parameters hermit-entry#38)
• Removing the unused networking hypercalls (we can add network related hypercalls later)
• Adding GetTime and Sleep hypercalls

This is a non-breaking change, as the old hypercall interface can still be implemented in uhhve. However, Currently, the memory where the hypercalls are mapped is mapped as regular memory. However, this will be changed in #725
The old interface can be marked deprecated and be removed in future versions.

[codecov]

Codecov Report

Attention: Patch coverage is 4.87805% with 39 lines in your changes missing coverage. Please review.

Project coverage is 67.57%. Comparing base (c0a8bac) to head (588a92d).

Files with missing lines	Patch %	Lines
uhyve-interface/src/v2/mod.rs	0.00%	22 Missing ⚠️
uhyve-interface/src/v1/mod.rs	5.55%	17 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #754      +/-   ##
==========================================
- Coverage   67.79%   67.57%   -0.23%     
==========================================
  Files          19       20       +1     
  Lines        2453     2461       +8     
==========================================
  Hits         1663     1663              
- Misses        790      798       +8     

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