A direct memory page mapped at one guest address now lives in private
MEM_WRITE_WATCH memory at that address, and its writes are collected with
GetWriteWatch like flexible memory: no fault is raised. A page mapped at a
second address moves its whole resident run into the section, behind a
read-only fence while it is copied, and every address becomes a view of it,
tracked by write protection. Unmapped resident pages that are not blank are
kept in a private reservation until they are mapped again, not in the
section.
Ported onto main's 4 KiB subpage tracking of shared views: resident runs
keep a per-page collected bit and enter the fresh ranges, so Fresh and
Armed collections select them like shared views; a demoted run carries its
collected bits into the views and reports every page once. MapAlias throws
through refuse() when a resident run extends outside the aliased range, and
the caller keeps main's fallback.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V1W4jdNSKTV7xwuS6xQPJV
d9852df2a2