diff --git a/.github/workflows/cifuzz.yml b/.github/workflows/cifuzz.yml
index d4c1e0921..2fb9db43c 100644
--- a/.github/workflows/cifuzz.yml
+++ b/.github/workflows/cifuzz.yml
@@ -1,5 +1,7 @@
 name: CIFuzz
-on: [pull_request]
+on:
+  push:
+    branches: [ main, release-branch/* ]
 
 concurrency:
   group: ${{ github.workflow }}-$${{ github.head_ref || github.run_id }}
@@ -7,7 +9,7 @@ concurrency:
 
 jobs:
   Fuzzing:
-    runs-on: ubuntu-latest
+    runs-on: buildjet-4vcpu-ubuntu-2204
     steps:
     - name: Build Fuzzers
       id: build
@@ -20,7 +22,7 @@ jobs:
       uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
       with:
         oss-fuzz-project-name: 'tailscale'
-        fuzz-seconds: 300
+        fuzz-seconds: 900
         dry-run: false
         language: go
     - name: Upload Crash
diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
index 84d5b903e..c02a8b5f6 100644
--- a/.github/workflows/codeql-analysis.yml
+++ b/.github/workflows/codeql-analysis.yml
@@ -27,7 +27,7 @@ concurrency:
 jobs:
   analyze:
     name: Analyze
-    runs-on: ubuntu-latest
+    runs-on: buildjet-4vcpu-ubuntu-2204
     permissions:
       actions: read
       contents: read
diff --git a/.github/workflows/cross-darwin.yml b/.github/workflows/cross-darwin.yml
index 5dfab485e..e6cc2b7c6 100644
--- a/.github/workflows/cross-darwin.yml
+++ b/.github/workflows/cross-darwin.yml
@@ -14,7 +14,7 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: buildjet-4vcpu-ubuntu-2204
 
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
 
diff --git a/.github/workflows/cross-freebsd.yml b/.github/workflows/cross-freebsd.yml
index 684e31cf2..0a7b2be7f 100644
--- a/.github/workflows/cross-freebsd.yml
+++ b/.github/workflows/cross-freebsd.yml
@@ -14,7 +14,7 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: buildjet-4vcpu-ubuntu-2204
 
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
 
diff --git a/.github/workflows/cross-openbsd.yml b/.github/workflows/cross-openbsd.yml
index cc4cd11b2..a65110450 100644
--- a/.github/workflows/cross-openbsd.yml
+++ b/.github/workflows/cross-openbsd.yml
@@ -14,7 +14,7 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: buildjet-4vcpu-ubuntu-2204
 
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
 
diff --git a/.github/workflows/cross-wasm.yml b/.github/workflows/cross-wasm.yml
index 60a397add..93f82e9f7 100644
--- a/.github/workflows/cross-wasm.yml
+++ b/.github/workflows/cross-wasm.yml
@@ -14,7 +14,7 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: buildjet-4vcpu-ubuntu-2204
 
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
 
diff --git a/.github/workflows/cross-windows.yml b/.github/workflows/cross-windows.yml
index 470cc4a2f..8950e79e0 100644
--- a/.github/workflows/cross-windows.yml
+++ b/.github/workflows/cross-windows.yml
@@ -14,7 +14,7 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: buildjet-4vcpu-ubuntu-2204
 
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
 
diff --git a/.github/workflows/linux-race.yml b/.github/workflows/linux-race.yml
index cd92d717c..70812b885 100644
--- a/.github/workflows/linux-race.yml
+++ b/.github/workflows/linux-race.yml
@@ -14,7 +14,7 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: buildjet-4vcpu-ubuntu-2204
 
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
 
diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index 228b701b5..be1945e51 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -14,7 +14,7 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: buildjet-4vcpu-ubuntu-2204
 
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
 
@@ -38,10 +38,6 @@ jobs:
 
     - name: Get QEMU
       run: |
-        # The qemu in Ubuntu 20.04 (Focal) is too old; we need 5.x something
-        # to run Go binaries. 5.2.0 (Debian bullseye) empirically works, and
-        # use this PPA which brings in a modern qemu.
-        sudo add-apt-repository -y ppa:jacob/virtualisation
         sudo apt-get -y update
         sudo apt-get -y install qemu-user
 
diff --git a/.github/workflows/linux32.yml b/.github/workflows/linux32.yml
index c0a64a702..1cea03e15 100644
--- a/.github/workflows/linux32.yml
+++ b/.github/workflows/linux32.yml
@@ -14,7 +14,7 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: buildjet-4vcpu-ubuntu-2204
 
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
 
diff --git a/.github/workflows/static-analysis.yml b/.github/workflows/static-analysis.yml
index b50cf5a9a..8b06be804 100644
--- a/.github/workflows/static-analysis.yml
+++ b/.github/workflows/static-analysis.yml
@@ -40,7 +40,7 @@ jobs:
       if: failure() && github.event_name == 'push'
 
   vet:
-    runs-on: ubuntu-latest
+    runs-on: buildjet-4vcpu-ubuntu-2204
     steps:
     - name: Set up Go
       uses: actions/setup-go@v3
@@ -66,7 +66,7 @@ jobs:
       if: failure() && github.event_name == 'push'
 
   staticcheck:
-    runs-on: ubuntu-latest
+    runs-on: buildjet-4vcpu-ubuntu-2204
     strategy:
       matrix:
         goos: [linux, windows, darwin]
diff --git a/.github/workflows/vm.yml b/.github/workflows/vm.yml
index 53989bc9e..9f56bec9d 100644
--- a/.github/workflows/vm.yml
+++ b/.github/workflows/vm.yml
@@ -11,7 +11,7 @@ concurrency:
 
 jobs:
   ubuntu2004-LTS-cloud-base:
-    runs-on: [ self-hosted, linux, vm ]
+    runs-on: buildjet-4vcpu-ubuntu-2204
 
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
 
@@ -27,12 +27,17 @@ jobs:
         with:
           go-version-file: go.mod
 
+      - name: Get QEMU
+        run: |
+          sudo apt-get -y update
+          sudo apt-get -y install qemu-system-x86 qemu-user genisoimage qemu-utils
+
       - name: Run VM tests
         run: go test ./tstest/integration/vms -v -no-s3 -run-vm-tests -run=TestRunUbuntu2004
         env:
           HOME: "/tmp"
           TMPDIR: "/tmp"
-          XDG_CACHE_HOME: "/var/lib/ghrunner/cache"
+          XDG_CACHE_HOME: "/home/runner/cache"
 
       - uses: k0kubun/action-slack@v2.0.0
         with:
diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index 7b5706635..2b319ccc1 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -14,7 +14,7 @@ concurrency:
 
 jobs:
   test:
-    runs-on: windows-latest
+    runs-on: [ self-hosted, Windows ]
 
     if: "!contains(github.event.head_commit.message, '[ci skip]')"