Description of the changes

During confidential VM creation, PageTable::copy_from_non_confidential_memory recursively traverses and copies the hypervisor's page table hierarchy into confidential memory, constructing the logical_representation for each page table level (up to 512 entries per page). Previously, building the entry list using .map(...).collect::Result<Vec, Error>>()? caused Rust's internal ResultShunt to report a lower size hint of 0 due to potential error short-circuiting. Consequently the vector started with capacity 0 and was repeatedly resized and reallocated on the heap as entries were processed. Because copy_from_non_confidential_memory runs recursively across every page table in the VM's address space, these redundant reallocations added noticeable latency to VM initialization and memory setup.

This PR replaced the map().collect::<Result<...>>()? pattern with .try_fold(Vec::with_capacity(), ...) eliminating all intermediate reallocations.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Formal verification
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactorization (non-breaking change which improves code quality)