membacking: label memory regions for smaps debugging

[jstarks]

Add SparseMapping::set_name() using prctl(PR_SET_VMA_ANON_NAME) on Linux to label anonymous mappings in /proc/{pid}/smaps. No-op on non-Linux platforms and Windows. Label the guest memory VA reservation as 'guest-memory' and private RAM allocations as 'guest-ram-private'.

Also add a name parameter to alloc_shared_memory() so memfd_create uses descriptive names visible as /memfd: in smaps: guest-ram, rom, vram, page-pool.

[github-actions]

⚠️ Unsafe Code Detected

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[Copilot]

Pull request overview

Adds optional, platform-appropriate naming for memory mappings to improve /proc/{pid}/smaps readability during debugging, and threads descriptive names through shared-memory allocation sites.

Changes:

• Add SparseMapping::set_name() (Linux prctl(PR_SET_VMA_ANON_NAME); no-op elsewhere) and use it to label guest VA reservations and private RAM allocations.
• Extend alloc_shared_memory() to accept a name so Linux memfd_create produces descriptive /memfd:<name> entries.
• Update call sites (tests/fuzz/OpenVMM/petri/page-pool) to pass appropriate mapping names (e.g., vram, rom, page-pool, guest-ram).

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
vm/page_pool_alloc/src/lib.rs	Passes a descriptive name (page-pool) into shared-memory allocation for smaps visibility.
support/sparse_mmap/src/windows.rs	Adds SparseMapping::set_name no-op and updates alloc_shared_memory signature to accept (ignored) name.
support/sparse_mmap/src/unix.rs	Implements Linux set_name via prctl, and threads name into memfd_create (and signature updates).
support/sparse_mmap/src/lib.rs	Updates tests to use new alloc_shared_memory(size, name) signature.
support/sparse_mmap/fuzz/fuzz_sparse_mmap.rs	Updates fuzz target to use new shared-memory allocation signature.
petri/src/vm/openvmm/construct.rs	Names VRAM shared memory (vram) for smaps debugging.
openvmm/openvmm_entry/src/lib.rs	Names VRAM shared memory (vram) for smaps debugging in CLI-driven VM construction.
openvmm/openvmm_core/src/worker/rom.rs	Names ROM shared memory (rom) for smaps debugging.
openvmm/membacking/src/memory_manager/mod.rs	Names guest RAM memfd (guest-ram) and private RAM anonymous mappings (guest-ram-private).
openvmm/membacking/src/mapping_manager/va_mapper.rs	Labels the guest VA reservation as guest-memory and exposes set_range_name().

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[github-actions]

At least one Petri test failed.

[smalis-msft]

Windows doesn't offer a similar feature? Unfortunate.

[Copilot]

Pull request overview

Adds smaps-friendly naming for guest memory mappings to improve debugging of OpenVMM memory usage on Linux, while keeping behavior as a no-op on non-Linux/Windows.

Changes:

• Introduce SparseMapping::set_name() (Linux via prctl(PR_SET_VMA_ANON_NAME), no-op elsewhere) and apply it to guest VA reservations and private RAM allocations.
• Extend alloc_shared_memory() to accept a descriptive name and pass it through to Linux memfd_create() (ignored on Windows / non-Linux Unix).
• Update call sites (OpenVMM, Petri, fuzz/tests) to provide descriptive names (e.g., guest-ram, rom, vram, page-pool).

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
vm/page_pool_alloc/src/lib.rs	Passes "page-pool" into alloc_shared_memory() for clearer memfd naming.
support/sparse_mmap/src/windows.rs	Adds no-op set_name() and updates alloc_shared_memory() signature to accept a name (ignored).
support/sparse_mmap/src/unix.rs	Implements Linux set_name() via prctl and threads name through memfd_create() / shm_open path.
support/sparse_mmap/src/lib.rs	Updates unit test to use new alloc_shared_memory(size, name) API.
support/sparse_mmap/fuzz/fuzz_sparse_mmap.rs	Updates fuzz harness to pass a name into alloc_shared_memory().
petri/src/vm/openvmm/construct.rs	Names VRAM shared memory "vram".
openvmm/openvmm_entry/src/lib.rs	Names VRAM shared memory "vram" for smaps visibility.
openvmm/openvmm_core/src/worker/rom.rs	Names ROM backing shared memory "rom".
openvmm/membacking/src/memory_manager/mod.rs	Names guest RAM shared memory "guest-ram" and labels private RAM ranges "guest-ram-private".
openvmm/membacking/src/mapping_manager/va_mapper.rs	Labels the VA reservation "guest-memory" and exposes set_range_name().

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[chris-oo]

other than stevens' comment about the CString conversion should never fail, LGTM. neat stuff

[github-actions]

At least one Petri test failed.