Add Wasmtime meeting minutes for 2022-02-17. (#3826)

Also move the verified fuzzing interpreter agenda item to today's agenda
from Mar 17, since it actually was discussed today.

meetings/wasmtime/2022/wasmtime-02-17.md

@@ -11,10 +11,91 @@
 1. Announcements
     1. _Submit a PR to add your announcement here_
 1. Other agenda items
-    1. _Submit a PR to add your item here_
+    1. Conrad Watt: verified Wasm interpreter as fuzzing oracle
 
 ## Notes
 
 ### Attendees
 
+- Conrad Watt
+- cfallin
+- acrichton
+- abrown
+- till
+- Dan
+- fitzgen
+- LGR
+- Anton Kirilov
+- Kevin Hoffman
+- jlbirch
+
 ### Notes
+
+- Spec interpreter and fuzzing (Conrad Watt)
+  - (slides)
+  - Conrad: reference interpreter; Wasmtime fuzzes with it; but quadratic
+    behavior
+  - Conrad: WasmCert-Isabelle (formally verified Wasm semantics) can extract an
+    interpreter; fixes quadratic behavior. Should we use this?
+  - fitzgen: does interpreter have a concept of execution fuel?
+  - Conrad: yes
+  - fitzgen: great; we can get rid of our wasm-smith fuel instrumentation
+  - Conrad: perf should be roughly equivalent to cfallin's fork of ref
+    interpreter with quadratic behavior fixed
+  - Conrad can open a PR
+  - Conrad: hazards: "teething pains" -- bugs once interpreter is exposed to fuzzing
+    - fitzgen: just fuzz locally a bit before turning on in ossfuzz
+  - Conrad: hazards: no line numbers
+    - cfallin: doesn't matter too much, we just verify that trap or no trap is
+      same on both sides
+  - abrown: add a toplevel CLI tool to run ref interpreter?
+  - Conrad: post-MVP story.
+    - SIMD: can defer to original ref interpreter
+    - cfallin: back to quadratic behavior then, or avoid?
+    - Conrad: no, just uses arithmetic library/semantics part
+  - cfallin: host interaction? GC, imports, etc
+    - Conrad: can call imports all the same; GC is mostly internal to interpreter
+  - fitzgen: multi-module?
+    - Conrad: should be handled
+  - Till: plans about component model?
+    - Conrad: two parts, standardized imports / WASI-like things, and semantics
+      of interface types
+    - Conrad: rely on polyfills for now
+    - fitzgen: module linking moved into component model, supporting that is
+      valuable
+    - Conrad: doable, needs Isabelle model of component model
+  - cfallin: can we fall back to unverified official reference interpreter at
+    the top level (for things like module linking, component model) in addition
+    to SIMD?
+    - Conrad: technically possible
+    - not clear whether this will be implemented in ref interpreter in same way
+      as "lower level" things like SIMD
+    - harder to do "middle-end" things like exception handling without
+      deferring all control flow back to unverified interpreter
+  - fitzgen: stack switching?
+    - Conrad: unclear current state; unaware of concrete proposal close to
+      being brought forward
+  - cfallin: future plans?
+    - Conrad: looking into reference types, bulk memory
+    - Conrad: within 6 mos-1 yr hope to support all currently standardized features
+    - Conrad: want to keep patce with standards track in general
+  - dgohman: checked against formal model in original Wasm paper?
+    - Conrad: "eyeball correspondence": formal model lines up with original
+      paper spec; then interpreter is mechanically verified against this formal
+      model
+
+- Till: CVE published yesterday in pooling allocator
+  - made us discuss more about ensuring we're fuzzing all configurations.
+    Previously had rule about fuzzing all implemented Wasm specs for two weeks;
+    now extended to all configs as well
+  - fitzgen wrote a GitHub bot to post a checklist on config changes ensuring this
+
+- cfallin: updates on memfd, lazy table, epochs
+  - instantiation got faster! SpiderMonkey.wasm instantiation from ~a few ms
+    down to 3µs
+  - not on by default in 0.34; should be in 0.35 (letting it bake in fuzzing
+    for one more week)
+  - epochs: faster way to do cooperative timeslicing than fuel; 1.5-2x better;
+    only downside is nondeterministism
+
+- Liam: KubeCon, call for talks

meetings/wasmtime/2022/wasmtime-03-17.md

@@ -11,7 +11,7 @@
 1. Announcements
     1. _Submit a PR to add your announcement here_
 1. Other agenda items
-    1. Conrad Watt: verified Wasm interpreter as fuzzing oracle
+    1. _Submit a PR to add your item here_
 
 ## Notes