openvmm: pin overflow-free memory-expansion ranges

doc/openvmm-upstream-roadmap.md

@@ -8,10 +8,11 @@
   reorganization kept it there; see [Upstream status](#upstream-status).
 - Mapped fork tip: `7677ad8d56a59864475012b63b6f01a22575c30d`, position 131. The graph, PR
   summary, and commit mapping below cover positions 001-131.
-- NVX's pinned OpenVMM revision: `b4028c1aa775d8aafba1a170857acc032c7c86a1`, position 235, the
-  head of microsoft/openvmm#5001, whose commit follows position 234, `f41a1ecfc`, the head of
-  `feature/microvm/dev`, which microsoft/openvmm#4997 merged after position 233, `d501e5066`,
-  which microsoft/openvmm#4996 merged after position 232, `6cb6ba87c`, which
+- NVX's pinned OpenVMM revision: `ac3dc27a738808d38e1148d3caefc5e89111ee32`, position 236, the
+  head of microsoft/openvmm#5003, whose commit follows position 235, `b4028c1aa`, the head of
+  `feature/microvm/dev`, which microsoft/openvmm#5001 merged after position 234, `f41a1ecfc`,
+  which microsoft/openvmm#4997 merged after position 233, `d501e5066`, which
+  microsoft/openvmm#4996 merged after position 232, `6cb6ba87c`, which
   microsoft/openvmm#4995 merged after position 231, `98e5b3ca5`, which
   microsoft/openvmm#4994 merged with position 230 after position 229, `ed8fc0713`, which
   microsoft/openvmm#4993 merged after position 228, `d6addf8c1`, which
@@ -28,8 +29,8 @@
   position 221 into positions 035 and 036, and combined v5.1 positions 222 and 223, the two commits
   of microsoft/openvmm#4984, into position 220. Positions 001-147 keep their positions, v5.1
   positions 149-220 are positions 148-219, and the tree of position 220 is the tree of
-  `3f2ab4c2f`; see [The v6.0 reorganization](#the-v60-reorganization). The pin is 104 commits past
-  the mapped tip on the same first-parent chain. Positions 132-235 are not yet assigned to PRs; see
+  `3f2ab4c2f`; see [The v6.0 reorganization](#the-v60-reorganization). The pin is 105 commits past
+  the mapped tip on the same first-parent chain. Positions 132-236 are not yet assigned to PRs; see
   [Commits after the mapped tip](#commits-after-the-mapped-tip).
 - Upstream main: `ba105dd7f00499acc1862456c179c0930cb2c8f7` (2026-11-06), the fork base itself;
   see [Upstream main past the fork base](#upstream-main-past-the-fork-base).
@@ -992,7 +993,8 @@ ba105dd7f
   -> clone's activation record carried in the restore packet [233]
   -> no-replace snapshot publication on every target [234]
   -> kernel tuning admitted on platform command lines [235]
-  -> b4028c1aa (NVX pin)
+  -> memory-expansion ranges placed without overflow [236]
+  -> ac3dc27a7 (NVX pin)
 ```
 
 For upstream review, PR01-PR06 and PR14 can be rebased independently onto current upstream main,
@@ -1008,13 +1010,13 @@ reorganization folded the PR20 and PR12 fixups into the commits that they fix; s
 
 ## Commits after the mapped tip
 
-The NVX pin extends the chain past position 131 without merges. None of the 104 later commits is a
+The NVX pin extends the chain past position 131 without merges. None of the 105 later commits is a
 fixup of a mapped PR, and none is yet classified or assigned to PRs. Each of positions 132-186
 combines the v2.4 commits that the table lists, as v3.0 positions 145-160 and 162-200 did, which
 developed one concept; "(part)" marks a v2.4 fixup that split across commits. Positions 187-191
 followed the v3.0 reorganization, positions 192-205 are the ABI restart of the v4.0
 reorganization, positions 206-211 followed it, positions 212-218 followed the v5.0
-reorganization, positions 219 and 220 followed the v5.1 rebase, and positions 221-235 followed the
+reorganization, positions 219 and 220 followed the v5.1 rebase, and positions 221-236 followed the
 v6.0 reorganization, so they combine none, apart from position 220, which combines v5.1 positions
 222 and 223. Each commit has the position that it
 had in v5.1 through position 147, and one less from v5.1 position 149 on; see
@@ -1127,6 +1129,7 @@ at `e1ca353eb`, whose first 210 commits are those of `feature/microvm/release/v4
 | 233 | `d501e5066` | - | - | - | - | microvm: carry a clone's activation record in the restore packet (microsoft/openvmm#4996) |
 | 234 | `f41a1ecfc` | - | - | - | - | openvmm_helpers: don't publish a snapshot over an empty directory (microsoft/openvmm#4997) |
 | 235 | `b4028c1aa` | - | - | - | - | openvmm_helpers: admit kernel tuning on platform command lines (microsoft/openvmm#5001) |
+| 236 | `ac3dc27a7` | - | - | - | - | openvmm_helpers: compute memory-expansion ranges without overflow (microsoft/openvmm#5003) |
 
 The remarks that say whether commits apply to upstream main record what the v3.0 reorganization
 found on its base, `b2676222b`, at the positions that the commits have now.
@@ -1250,7 +1253,10 @@ Position 235 changes the platform tier's check of a snapshot's command line, whi
 allowlist of the command line's tokens also admits a closed set of kernel tuning parameters, and
 the check refuses a command line that repeats one of them, after position 097's check of the
 boot-online processor count. It also extends the `--snapshot-tier` entry that position 093 adds to
-the CLI reference.
+the CLI reference. Position 236 changes how the canonical memory-expansion ranges that PR20's
+position 099 adds to the machine contract of PR17's position 074 compute their start, which
+overflowed for a base RAM of at least 2^64 - 4 GiB, and adds a test beside position 099's tests
+of the memory capacity.
 Assigning the later commits therefore means revisiting those PRs, not only appending new ones.
 
 Position 177, by contrast, changes only `disk_blob`, which upstream main and the fork base
@@ -1490,6 +1496,13 @@ Replaying it on upstream main conflicts in both of its files: upstream main lack
 snapshot module of position 074, the tiers of position 093, and the microVM CLI of position 064, so
 it follows PR15, PR17, and PR19 upstream.
 
+Position 236 changes only the memory-expansion ranges of the microVM snapshot module of
+`openvmm_helpers`, which PR17's position 074 adds and PR20's position 099 extends with those
+ranges, and adds a test to that module, which uses the expandable-memory manifest of position 099.
+Replaying it on upstream main conflicts in its only file: upstream main lacks the microVM snapshot
+module of position 074 and the memory expansion of position 099, so it follows PR17 and PR20
+upstream.
+
 ## PR summary
 
 Each count is of v6.0 commits, which include the fixups that the v3.0, v4.0, v5.0, and v6.0