dotfiles: drop the non-elevated ETW tracing, it never worked

[dotfiles] / README.md

diff --git a/README.md b/README.md
index e9b2005a102612211dd1725b2dc1449c1c3d842d..7c986501ecf46e0774cc835dd779883fad3bcc3f 100644 (file)
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ throwaway VM reachable from a Linux host.
 | --- | --- |
 | `setup-windows.bat` | Entry point. Runs the winget installs, then launches the elevated half and prints its log, then runs the non-elevated script. |
 | `setup-windows-no-uac.ps1` | The non-elevated, per-user half: WinMerge and BinSkim on the user `PATH`, and the global git config (identity, plus `core.sshCommand`). Can also be run directly from an ordinary prompt. |
 | --- | --- |
 | `setup-windows.bat` | Entry point. Runs the winget installs, then launches the elevated half and prints its log, then runs the non-elevated script. |
 | `setup-windows-no-uac.ps1` | The non-elevated, per-user half: WinMerge and BinSkim on the user `PATH`, and the global git config (identity, plus `core.sshCommand`). Can also be run directly from an ordinary prompt. |

-| `setup-windows-with-uac.ps1` | The elevated half, started via UAC by the batch file. Enables `ssh-agent`, installs the OpenSSH Client and Server capabilities and starts `sshd`, unpacks the `rsync-windows` release zip for this architecture (`rsync.exe` plus the `ssh.exe` it runs) into `C:\Tools\rsync` on the machine `PATH`, then installs Visual Studio 2022 Community with the required components, the WDK, and the Windows Performance Toolkit, and reports whether Intel VTune Profiler is present. It also puts one ordinary account into `Performance Log Users`, so it can run user-mode ETW sessions unelevated. Can also be run directly from an Administrator prompt — pass `-TraceUser DOMAIN\user` to name that account, and `-EtwRightsOnly` to do that step alone. |
+| `setup-windows-with-uac.ps1` | The elevated half, started via UAC by the batch file. Enables `ssh-agent`, installs the OpenSSH Client and Server capabilities and starts `sshd`, unpacks the `rsync-windows` release zip for this architecture (`rsync.exe` plus the `ssh.exe` it runs) into `C:\Tools\rsync` on the machine `PATH`, then installs Visual Studio 2022 Community with the required components, the WDK, and the Windows Performance Toolkit, and reports whether Intel VTune Profiler is present. Can also be run directly from an Administrator prompt. |

 | `setup-windows-7-test-env.bat` | Prepares a **Windows 7 VM** as a test target driven from the host by `VBoxManage guestcontrol`. Copy it into the guest and run it there; it is idempotent, so re-run it after any snapshot restore. The per-user half needs no UAC (crash-dialog suppression, no screen blanking, a staging directory, the shared folder on `Z:`); the machine-wide half is skipped with a notice unless run elevated inside the guest. It then reports what the box can actually test: DWM composition, printers, audio capture devices. |
 
 ## Usage
 | `setup-windows-7-test-env.bat` | Prepares a **Windows 7 VM** as a test target driven from the host by `VBoxManage guestcontrol`. Copy it into the guest and run it there; it is idempotent, so re-run it after any snapshot restore. The per-user half needs no UAC (crash-dialog suppression, no screen blanking, a staging directory, the shared folder on `Z:`); the machine-wide half is skipped with a notice unless run elevated inside the guest. It then reports what the box can actually test: DWM composition, printers, audio capture devices. |
 
 ## Usage


@@ -151,71 +151,52 @@ throwaway VM reachable from a Linux host.
   intel-vtune-<version>_offline.exe -a --silent --cli --eula accept
   ```
 
   intel-vtune-<version>_offline.exe -a --silent --cli --eula accept
   ```
 

-  **Running it needs no elevation, but hardware sampling does.** A standard user
-  gets the User-Mode Sampling analyses — `vtune -collect hotspots` and threading
-  — and they work: measured here, collection and finalization, exit 0. Hardware
-  event-based sampling (`uarch-exploration`, `memory-access`, `hotspots -knob
-  sampling-mode=hw`) wants administrator, and VTune says so in a warning at the
-  top of every unelevated run. Note the failure it actually gives is *"cannot
+  **Run it from an administrator account, elevated.** Hardware event-based
+  sampling (`uarch-exploration`, `memory-access`, `hotspots -knob
+  sampling-mode=hw`) requires it, and VTune warns about that at the top of every
+  unelevated run. Worth knowing that the failure it gives there is *"cannot

   recognize the processor"*, which reads like a hardware problem and is not one:
   the drivers (`sepdrv5`, `sepdal`, `vtss`) are installed and running, and VTune
   recognize the processor"*, which reads like a hardware problem and is not one:
   the drivers (`sepdrv5`, `sepdal`, `vtss`) are installed and running, and VTune

-  identifies the PMU through them. Unlike ETW there is no group to join for this
-  — the Linux driver can be handed to a `vtune` group, but on Windows the
+  identifies the PMU through them. There is no group to join to get around it —
+  the Linux driver can be handed to a `vtune` group, but on Windows the

   documented answer is to run as administrator.
 
   documented answer is to run as administrator.
 

-- **User-mode ETW tracing without a UAC prompt — and the kernel logger's hard
-  limit.** Out of the box a standard user cannot start *any* event tracing
-  session, not even a user-mode one naming a single provider:
+- **Collect traces from an elevated Administrator session. Non-elevated
+  collection was tried here and abandoned.** The attempt was to put one ordinary
+  account into `BUILTIN\Performance Log Users`, which appears in the default
+  security descriptors ETW keeps per provider GUID under
+  `HKLM\SYSTEM\CurrentControlSet\Control\WMI\Security`, and collect without a UAC
+  prompt. It does not survive contact with the real workflow: `xperf -on base`
+  and `wpr -start` drive the *NT Kernel Logger*, reserved for Administrators and
+  LocalSystem, and granting the group `SeSystemProfilePrivilege` ("Profile system
+  performance") plus an explicit ACE for `TRACELOG_ACCESS_KERNEL_LOGGER` on
+  `SystemTraceControlGuid` — all three in place, across a reboot — still answered

 
   ```text
 
   ```text

-  xperf -start T -on Microsoft-Windows-Kernel-Process -f trace.etl
-      -> Access is denied. (0x5)
+  xperf: error: NT Kernel Logger: Access is denied. (0x5).

   ```
 
   ```
 

-  Session control is checked against the security descriptor ETW keeps per
-  provider GUID under `HKLM\SYSTEM\CurrentControlSet\Control\WMI\Security`, whose
-  default grants those rights to SYSTEM, Administrators, the service accounts and
-  `BUILTIN\Performance Log Users` — and to nobody else. So the elevated half puts
-  the account named by `-TraceUser` into that group, and the command above then
-  works unelevated; enabling another account later is just
-  `net localgroup "Performance Log Users" <user> /add`. Membership is read into
-  the access token **at logon**, so sign out and back in first — any new logon
-  does it, and an `ssh` login into the box is the quick way to check without
-  dropping the desktop.
-
-  **Kernel traces are not available this way, and cannot be made to be.**
-  `xperf -on base` and `wpr -start` drive the *NT Kernel Logger*, which is
-  reserved for Administrators and LocalSystem — Microsoft documents Performance
-  Log Users access as explicitly not extending to it. That was measured rather
-  than assumed, and the negative result is recorded here so nobody repeats the
-  experiment: with the account in the group, `SeSystemProfilePrivilege` ("Profile
-  system performance") granted to that group, and an explicit ACE giving the
-  group `TRACELOG_ACCESS_KERNEL_LOGGER` on `SystemTraceControlGuid` — all three
-  in place, across a reboot — `xperf -on base` still answered `NT Kernel Logger:
-  Access is denied. (0x5)`. It is not a check an ACE overrides. The privilege
-  grant and the ACE were dropped again rather than left on the box earning
-  nothing: CPU sampling and whole-system traces are elevated work, with `xperf`,
-  `wpr` or VTune from an Administrator prompt.
-
-  Analysis was never affected — `wpa.exe` opens an existing `.etl` as a plain
-  user. This is only about collection.
-
-  The step runs **first** in the elevated half, and `-EtwRightsOnly` runs it and
-  nothing else, which matters because a full run is dominated by the three Visual
-  Studio passes that take minutes even with nothing to do:
+  It is not a check an ACE overrides, and the same wall turned up often enough
+  elsewhere that the whole approach was dropped rather than carried as a
+  half-working path. **Sign in to an administrator account and run `xperf`, `wpr`
+  and VTune from an elevated prompt.** Analysis is the exception and never needed
+  any of this: `wpa.exe` opens an existing `.etl` as a plain user.
+
+  If an earlier revision of these scripts ran on a box, it left that account in
+  the group. Take it back out with:

 
   ```powershell
 
   ```powershell

-  Start-Process powershell -Verb RunAs -ArgumentList '-NoProfile','-ExecutionPolicy','Bypass',
-      '-File','<repo>\setup-windows-with-uac.ps1','-TraceUser','DOMAIN\user','-EtwRightsOnly'
+  net localgroup "Performance Log Users" DOMAIN\user /delete

   ```
 
   ```
 

-  If you ran an earlier revision of this script, it left both of the grants above
-  on the box. Undo the privilege in `secpol.msc` > Local Policies > User Rights
-  Assignment > "Profile system performance" by removing Performance Log Users.
-  The ACEs sit in the `{9e814aad-3204-11d2-9a82-006008a86939}` value under
+  Two revisions also granted the privilege and the ACE. Undo the privilege in
+  `secpol.msc` > Local Policies > User Rights Assignment > "Profile system
+  performance" by removing Performance Log Users. The ACEs sit in the
+  `{9e814aad-3204-11d2-9a82-006008a86939}` value under

   `HKLM\SYSTEM\CurrentControlSet\Control\WMI\Security`: strip the `LU` entries
   from that descriptor rather than deleting the value, which also carries entries
   for SYSTEM, Administrators and two service accounts.
   `HKLM\SYSTEM\CurrentControlSet\Control\WMI\Security`: strip the `LU` entries
   from that descriptor rather than deleting the value, which also carries entries
   for SYSTEM, Administrators and two service accounts.

+

 - The scripts were extracted from a native Windows project, so the component
   selection is tuned for that: Spectre-mitigated runtimes, the v141/XP toolset,
   and driver-kit headers. Trim the component lists in the `.ps1` if you don't
 - The scripts were extracted from a native Windows project, so the component
   selection is tuned for that: Spectre-mitigated runtimes, the v141/XP toolset,
   and driver-kit headers. Trim the component lists in the `.ps1` if you don't