Move and rename some Vm traits

[ludfjig]

Some follow up items from #924. Please review commit by commit

• Moves kvm.rs/hyperv_linux.rs/hyperv_windows.rs into new vm module.
• Renames Hyperv_linux.rs to mshv.rs. Renames hyperv_windows.rs to whp.rs
• Renames Hypervisor trait to Vm trait
• Renames HyperlightExit to VmExit
• Moves some hypervisor specific code out from sandbox module, to hypervisor/vm module

Note that this PR does not modify any code (with exception of renames and moves)

[Copilot]

Pull request overview

This PR performs a significant refactoring of VM-related code to improve organization and naming consistency. It moves hypervisor-specific implementation files from the root hypervisor module and the sandbox module into a new hypervisor/vm submodule, renames files to use shorter and more descriptive names (mshv, whp), and renames core abstractions (Hypervisor trait → Vm trait, HyperlightExit → VmExit) to better reflect their purpose.

Key Changes:

• Created new hypervisor/vm module to consolidate VM implementations (KVM, MSHV, WHP)
• Renamed Hypervisor trait to Vm and HyperlightExit enum to VmExit for clearer semantics
• Moved hypervisor detection logic from sandbox::hypervisor to hypervisor::vm

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/hyperlight_host/src/sandbox/mod.rs	Removed hypervisor submodule and moved is_hypervisor_present() to hypervisor/vm module
src/hyperlight_host/src/sandbox/hypervisor.rs	Deleted - functionality moved to hypervisor/vm/mod.rs
src/hyperlight_host/src/lib.rs	Updated public export to reference hypervisor::vm::is_hypervisor_present
src/hyperlight_host/src/hypervisor/vm/mod.rs	New module containing VM trait, VmExit enum, hypervisor detection, and test moved from sandbox
src/hyperlight_host/src/hypervisor/vm/whp.rs	Renamed from hyperv_windows.rs; updated trait implementation and imports
src/hyperlight_host/src/hypervisor/vm/mshv.rs	Renamed from hyperv_linux.rs; updated trait implementation and imports
src/hyperlight_host/src/hypervisor/vm/kvm.rs	Moved to vm submodule; updated trait implementation and imports
src/hyperlight_host/src/hypervisor/mod.rs	Removed Hypervisor trait, HyperlightExit enum, and old module declarations
src/hyperlight_host/src/hypervisor/hyperlight_vm.rs	Updated imports to reference vm module and new Vm/VmExit names; updated comments
src/hyperlight_host/src/hypervisor/gdb/mod.rs	Updated DebuggableVm trait to extend Vm instead of Hypervisor

[danbugs]

I like the change from Hypervisor → Vm. I agree that it is more accurate. Same for VmExit over HyperlightExit.

Though, iirc, in the past, when we considered changing from hyperv_* to mshv/whp, we opted to keep the previous names.

[ludfjig]

I like the change from Hypervisor → Vm. I agree that it is more accurate. Same for VmExit over HyperlightExit.

Though, iirc, in the past, when we considered changing from hyperv_* to mshv/whp, we opted to keep the previous names.

THanks. I think the renaming was discarded in the past due to making a PR too hard to review

[danbugs]

I like the change from Hypervisor → Vm. I agree that it is more accurate. Same for VmExit over HyperlightExit.
Though, iirc, in the past, when we considered changing from hyperv_* to mshv/whp, we opted to keep the previous names.

THanks. I think the renaming was discarded in the past due to making a PR too hard to review

I think Simon also mentioned the hyperv_* names are more descriptive: #517 (comment)

[jsturtevant]

LGTM, I tend to agree that I perfer hyperv_linux and hyperv_windows over mshv and whp.

[ludfjig]

I like whp (windows hypervisor platform) because it's the name of the API we use https://learn.microsoft.com/en-us/virtualization/api/hypervisor-platform/hypervisor-platform