fix(swingset): retain vatParameters for vat creation and upgrade

All vats have `vatParameters`, a mostly-arbitrary data record,
delivered as the second argument to their `buildRootObject()`
function. Dynamic vats get their vatParameters from the options bag
given to `E(vatAdminSvc).createVat()`. Static vats get them from the
kernel config record. When a vat is upgraded, the new incarnation gets
new vatParameters; these come from the options bag on
`E(vatAdminSvc).upgradeVat()`.

When received via `createVat()` or `upgradeVat()`, the vatParameters
can contain object and device references. VatParameters cannot include
promises.

Previously, the kernel delivered vatParameters to the vat, but did not
keep a copy. With this commit, the kernel retains a copy of
vatParameters (including a refcount on any kernel objects
therein). Internally, `vatKeeper.getVatParameters()` can be used to
retrieve this copy.  Only vats created or upgraded after this commit
lands will get retained vatParameters: for older vats this will return
`undefined`.

Retained vat parameters should make it easier to implement "upgrade
all vats", where the kernel perform a unilateral `upgradeVat()` on all
vats without userspace asking for it. When this is implemented, the
new incarnations will receive the same vatParameters as their
predecessors.

fixes #8947

packages/SwingSet/src/kernel/kernel.js

@@ -743,6 +743,8 @@ export default function buildKernel(
       kdebug(`vat ${vatID} terminated before startVat delivered`);
       return NO_DELIVERY_CRANK_RESULTS;
     }
+    const vatKeeper = kernelKeeper.provideVatKeeper(vatID);
+    vatKeeper.setVatParameters(vatParameters);
     const { meterID } = vatInfo;
     /** @type { KernelDeliveryStartVat } */
     const kd = harden(['startVat', vatParameters]);
@@ -1022,6 +1024,7 @@ export default function buildKernel(
     });
     const vatOptions = harden({ ...origOptions, workerOptions });
     vatKeeper.setSourceAndOptions(source, vatOptions);
+    vatKeeper.setVatParameters(vatParameters);
     // TODO: decref the bundleID once setSourceAndOptions increfs it
 
     // pause, take a deep breath, appreciate this moment of silence

packages/SwingSet/src/kernel/state/kernelKeeper.js

@@ -117,6 +117,8 @@ export const CURRENT_SCHEMA_VERSION = 2;
 // old (v0): v$NN.reapCountdown = $NN or 'never'
 // v$NN.reapDirt = JSON({ deliveries, gcKrefs, computrons }) // missing keys treated as zero
 // (leave room for v$NN.snapshotDirt and options.snapshotDirtThreshold for #6786)
+// v$NN.vatParameters = JSON(capdata) // missing for vats created/upgraded before #8947
+//
 // exclude from consensus
 // local.*
 

packages/SwingSet/src/kernel/state/vatKeeper.js

@@ -7,6 +7,7 @@ import { isObject } from '@endo/marshal';
 import { parseKernelSlot } from '../parseKernelSlots.js';
 import { makeVatSlot, parseVatSlot } from '../../lib/parseVatSlots.js';
 import { insistVatID } from '../../lib/id.js';
+import { insistCapData } from '../../lib/capdata.js';
 import { kdebug } from '../../lib/kdebug.js';
 import {
   parseReachableAndVatSlot,
@@ -173,6 +174,35 @@ export function makeVatKeeper(
     return harden(options);
   }
 
+  /**
+   * @param {SwingSetCapData} newVPCD
+   */
+  function setVatParameters(newVPCD) {
+    insistCapData(newVPCD);
+    const key = `${vatID}.vatParameters`;
+    // increment-before-decrement to minimize spurious rc=0 checks
+    for (const kref of newVPCD.slots) {
+      incrementRefCount(kref, `${vatID}.vp`);
+    }
+    const old = kvStore.get(key) || '{"slots":[]}';
+    for (const kref of JSON.parse(old).slots) {
+      decrementRefCount(kref, `${vatID}.vp`);
+    }
+    kvStore.set(key, JSON.stringify(newVPCD));
+  }
+
+  /**
+   * @returns {SwingSetCapData | undefined} vpcd
+   */
+  function getVatParameters() {
+    const key = `${vatID}.vatParameters`;
+    const old = kvStore.get(key);
+    if (old) {
+      return JSON.parse(old);
+    }
+    return undefined;
+  }
+
   // This is named "addDirt" because it should increment all dirt
   // counters (both for reap/BOYD and for heap snapshotting). We don't
   // have `heapSnapshotDirt` yet, but when we do, it should get
@@ -768,6 +798,8 @@ export function makeVatKeeper(
     setSourceAndOptions,
     getSourceAndOptions,
     getOptions,
+    setVatParameters,
+    getVatParameters,
     addDirt,
     getReapDirt,
     clearReapDirt,

packages/SwingSet/test/state.test.js

@@ -592,6 +592,44 @@ test('vatKeeper.getOptions', async t => {
   t.is(name, 'fred');
 });
 
+test('vatKeeper.setVatParameters', async t => {
+  const store = buildKeeperStorageInMemory();
+  const k = makeKernelKeeper(store, 'uninitialized');
+  k.createStartingKernelState({ defaultManagerType: 'local' });
+  k.setInitialized();
+  const v1 = k.allocateVatIDForNameIfNeeded('name1');
+  const bundleID =
+    'b1-00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000';
+  const source = { bundleID };
+  const workerOptions = { type: 'local' };
+  const options = { workerOptions, name: 'fred', reapDirtThreshold: {} };
+  k.createVatState(v1, source, options);
+
+  const vk = k.provideVatKeeper(v1);
+  const ko1 = kslot('ko1');
+  const ko2 = kslot('ko2');
+  const vp1 = kser({ foo: 1, bar: ko1, baz: ko1 });
+  vk.setVatParameters(vp1);
+  t.deepEqual(JSON.parse(store.kvStore.get('v1.vatParameters')), vp1);
+  t.is(store.kvStore.get('ko1.refCount'), '1,1');
+  t.deepEqual(vk.getVatParameters(), vp1);
+
+  const vp2 = kser({ foo: 1, bar: ko1, baz: ko2 });
+  vk.setVatParameters(vp2);
+  t.deepEqual(JSON.parse(store.kvStore.get('v1.vatParameters')), vp2);
+  t.is(store.kvStore.get('ko1.refCount'), '1,1');
+  t.is(store.kvStore.get('ko2.refCount'), '1,1');
+  t.deepEqual(vk.getVatParameters(), vp2);
+
+  const vp3 = kser({ foo: 1, baz: ko2 });
+  vk.setVatParameters(vp3);
+  t.deepEqual(JSON.parse(store.kvStore.get('v1.vatParameters')), vp3);
+  // this test doesn't do processRefcounts, which would remove the 0,0
+  t.is(store.kvStore.get('ko1.refCount'), '0,0');
+  t.is(store.kvStore.get('ko2.refCount'), '1,1');
+  t.deepEqual(vk.getVatParameters(), vp3);
+});
+
 test('XS vatKeeper defaultManagerType', async t => {
   const store = buildKeeperStorageInMemory();
   const k = makeKernelKeeper(store, 'uninitialized');

packages/SwingSet/test/upgrade/bootstrap-scripted-upgrade.js

@@ -265,5 +265,26 @@ export const buildRootObject = () => {
 
       return [paramA, paramB];
     },
+
+    buildV1WithVatParameters: async () => {
+      const bcap1 = await E(vatAdmin).getNamedBundleCap('ulrik1');
+      const vp1 = { number: 1, marker };
+      const options1 = { vatParameters: vp1 };
+      const res = await E(vatAdmin).createVat(bcap1, options1);
+      ulrikAdmin = res.adminNode;
+      ulrikRoot = res.root;
+      const param1 = await E(ulrikRoot).getParameters();
+      return param1;
+    },
+
+    upgradeV2WithVatParameters: async () => {
+      const bcap2 = await E(vatAdmin).getNamedBundleCap('ulrik2');
+      const vp2 = { number: 2, marker };
+      const options2 = { vatParameters: vp2 };
+      await E(ulrikAdmin).upgrade(bcap2, options2);
+      const param2 = await E(ulrikRoot).getParameters();
+
+      return param2;
+    },
   });
 };

packages/SwingSet/test/upgrade/upgrade.test.js

@@ -930,3 +930,40 @@ test('failed vatAdmin upgrade - bad replacement code', async t => {
   // Just a taste to verify that the create went right; other tests check the rest
   t.deepEqual(v1result.data, ['some', 'data']);
 });
+
+test('vat upgrade retains vatParameters', async t => {
+  const config = makeConfigFromPaths('bootstrap-scripted-upgrade.js', {
+    defaultManagerType: 'xs-worker',
+    defaultReapInterval: 'never',
+    bundlePaths: {
+      ulrik1: 'vat-ulrik-1.js',
+      ulrik2: 'vat-ulrik-2.js',
+    },
+  });
+  const kft = await initKernelForTest(t, t.context.data, config);
+  const { messageToVat, kvStore } = kft;
+
+  // create initial version
+  const params1 = await messageToVat('bootstrap', 'buildV1WithVatParameters');
+  t.is(params1.number, 1);
+  const marker = params1.marker;
+  t.deepEqual(params1, { number: 1, marker });
+  const markerKref = marker.getKref();
+
+  // confirm the vatParameters were recorded in kvStore
+  const vatID = JSON.parse(kvStore.get('vat.dynamicIDs'))[0];
+  const vp1cd = kvStore.get(`${vatID}.vatParameters`);
+  const vp1 = kunser(JSON.parse(vp1cd));
+  t.is(vp1.number, 1);
+  t.is(vp1.marker.getKref(), markerKref);
+
+  // upgrade
+  const params2 = await messageToVat('bootstrap', 'upgradeV2WithVatParameters');
+  t.is(params2.number, 2);
+  t.is(params2.marker.getKref(), markerKref);
+  // kvStore should now hold the new vatParameters
+  const vp2cd = kvStore.get(`${vatID}.vatParameters`);
+  const vp2 = kunser(JSON.parse(vp2cd));
+  t.is(vp2.number, 2);
+  t.is(vp2.marker.getKref(), markerKref);
+});

packages/SwingSet/test/vat-admin/create-vat.test.js

@@ -276,13 +276,20 @@ test('createVat holds refcount', async t => {
   const { c, idRC, kernelStorage } = await doTestSetup(t, false, printSlog);
   const { kvStore } = kernelStorage;
 
+  // we typicaly get: v1-bootstrap, v2-vatAdmin, v6-export-held
+  // for (const name of JSON.parse(kvStore.get('vat.names'))) {
+  //   console.log(`${kvStore.get(`vat.name.${name}`)}: ${name}`);
+  // }
+  // and d7-vatAdmin
+
   // The bootstrap vat starts by fetching 'held' from vat-export-held, during
   // doTestSetup(), and retains it throughout the entire test. When we send
   // it refcount(), it will send VatAdminService.getBundleCap(), wait for the
   // response, then send VatAdminService.createVat(held). VAS will tell
   // device-vat-admin to push a create-vat event (including 'held') on the
   // run-queue. Some time later, the create-vat event reaches the front, and
-  // the new vat is created, receiving 'held' in vatParametesr.
+  // the new vat is created, receiving 'held' in vatParameters. The kernel
+  // retains a copy of those vatParameters for any future unilateral upgrade.
 
   // We want to check the refcounts during this sequence, to confirm that the
   // create-vat event holds a reference. Otherwise, 'held' might get GCed
@@ -292,7 +299,7 @@ test('createVat holds refcount', async t => {
   // nothing ever decrements it: devices hold eternal refcounts on their
   // c-list entries, and nothing ever removes a device c-list entry. But some
   // day when we fix that, we'll rely upon the create-vat event's refcount to
-  // keep these things alive.
+  // keep these things alive.)
 
   // We happen to know that 'held' will be allocated ko27, but we use
   // `getHeld()` to obtain the real value in case e.g. a new built-in vat is
@@ -365,9 +372,11 @@ test('createVat holds refcount', async t => {
   expectedRefcount -= 1; // kpid1 deleted, drops ref to 'held', now 2,2
   // it also does syscall.send(createVat), which holds a new reference
   expectedRefcount += 1; // arg to 'createVat'
-  // now we should see 3,3: v1-bootstrap, the kpResolution pin, and the
-  // send(createVat) arguments. Two of these are c-lists.
+  // now we should see 3,3: v1-bootstrap, the kpResolution pin, and
+  // the send(createVat) arguments. For c-lists, it is present in v1.c
+  // (import) and v6.c (export)
   const r1 = findRefs(kvStore, held);
+  // console.log(`r1:`, JSON.stringify(r1));
   t.deepEqual(r1.refcount, [expectedRefcount, expectedRefcount]);
   t.is(r1.refs.length, expectedCLists);
   // console.log(`---`);
@@ -384,13 +393,13 @@ test('createVat holds refcount', async t => {
   await stepUntil(seeCreateVat);
   // console.log(`---`);
 
-  // We should see 5,5: v2-bootstrap, the kpResolution pin, vat-vat-admin,
-  // device-vat-admin, and the create-vat run-queue event. Three of these are
-  // c-lists.
-  expectedRefcount += 1; // vat-vat-admin c-list
-  expectedCLists += 1; // vat-vat-admin c-list
-  expectedRefcount += 1; // device-vat-admin c-list
-  expectedCLists += 1; // device-vat-admin c-list
+  // We should see 5,5: v1-bootstrap, the kpResolution pin,
+  // v2-vatAdmin, d7-vatAdmin, and the create-vat run-queue
+  // event. c-lists: v1/v2/d7 imports, v6 export
+  expectedRefcount += 1; // v2-vatAdmin c-list
+  expectedCLists += 1; // v2-vatAdmin c-list
+  expectedRefcount += 1; // d7-vatAdmin c-list
+  expectedCLists += 1; // d7-vatAdmin c-list
 
   const r2 = findRefs(kvStore, held);
   // console.log(`r2:`, JSON.stringify(r2));
@@ -400,8 +409,8 @@ test('createVat holds refcount', async t => {
   // Allow the vat-admin bringOutYourDead to be delivered, which
   // allows it to drop its reference to 'held'.
 
-  expectedRefcount -= 1; // vat-vat-admin retires
-  expectedCLists -= 1; // vat-vat-admin retires
+  expectedRefcount -= 1; // v2-vatAdmin retires
+  expectedCLists -= 1; // v2-vatAdmin retires
 
   // In addition, device-vat-admin does not yet participate in GC, and holds
   // its references forever. So this -=1 remains commented out until we
@@ -415,25 +424,27 @@ test('createVat holds refcount', async t => {
   t.deepEqual(c.dump().reapQueue, []);
   // console.log(`---`);
 
-  // At this point we expected to see 5,5: v2-bootstrap, kpResolution pin,
-  // vat-vat-admin (because of the non-dropping bug), device-vat-admin
-  // (because of unimplemented GC), and the create-vat run-queue event. Two
-  // are c-lists.
+  // At this point we expected to see 4,4: v1-bootstrap, kpResolution
+  // pin, d7-vatAdmin (because of unimplemented GC), and the
+  // create-vat run-queue event. c-lists: v1/d7 imports, v6 export
 
   const r3 = findRefs(kvStore, held);
   // console.log(`r3:`, JSON.stringify(r3));
   t.deepEqual(r3.refcount, [expectedRefcount, expectedRefcount]);
   t.is(r3.refs.length, expectedCLists);
 
-  // Allow create-vat to be processed, removing the create-vat reference and
-  // adding a reference from the new vat's c-list
+  // Allow create-vat to be processed, removing the create-vat
+  // reference and adding a reference from the new vat's c-list, plus
+  // a second reference from the retained vatParameters
   await c.step();
   expectedRefcount -= 1; // remove send(createVat) argument
   expectedRefcount += 1; // new-vat c-list
+  expectedRefcount += 1; // retained vatParameters
   expectedCLists += 1; // new-vat c-list
   // console.log(`---`);
 
-  // v2-bootstrap, kpResolution pin, device-vat-admin, new-vat
+  // v1-bootstrap, kpResolution pin, d7-vatAdmin, new-vat, retained
+  // vatParameters
   const r4 = findRefs(kvStore, held);
   // console.log(`r4:`, JSON.stringify(r4));
   t.deepEqual(r4.refcount, [expectedRefcount, expectedRefcount]);