From 40ffbd5093d6f9a6ea584c01aedb40c87231abdd Mon Sep 17 00:00:00 2001
From: Elliot Michlin <31219104+theelliotm@users.noreply.github.com>
Date: Mon, 21 Sep 2026 12:03:43 -0700
Subject: [PATCH 1/3] wslc scripts now check for ARM target on ARM systems

---
 scripts/setup-wslc.ps1                         |  6 +++++-
 tests/scripts/run_wslc_all_tests.ps1           | 11 ++++++++---
 tests/scripts/run_wslc_denied_masking_test.ps1 |  9 +++++++--
 tests/scripts/run_wslc_dotdot_alias_test.ps1   |  9 +++++++--
 tests/scripts/run_wslc_most_specific_test.ps1  |  9 +++++++--
 tests/scripts/run_wslc_object_test.ps1         |  9 +++++++--
 tests/scripts/run_wslc_proxy_test.ps1          |  9 +++++++--
 tests/scripts/run_wslc_state_aware_tests.ps1   |  8 +++++++-
 8 files changed, 55 insertions(+), 15 deletions(-)

diff --git a/scripts/setup-wslc.ps1 b/scripts/setup-wslc.ps1
index e37e79046..f931bafd7 100644
--- a/scripts/setup-wslc.ps1
+++ b/scripts/setup-wslc.ps1
@@ -66,7 +66,11 @@ $ErrorActionPreference = "Stop"
 $RepoRoot = Split-Path -Parent $PSScriptRoot
 
 # Discover wxc-exec.exe -- prefer explicit path, then probe target dirs.
-$Target = "x86_64-pc-windows-msvc"
+$Target = if ($env:PROCESSOR_ARCHITECTURE -eq 'ARM64') {
+    'aarch64-pc-windows-msvc'
+} else {
+    'x86_64-pc-windows-msvc'
+}
 if ($WxcExecPath) {
     $WxcExec = $WxcExecPath
 } else {
diff --git a/tests/scripts/run_wslc_all_tests.ps1 b/tests/scripts/run_wslc_all_tests.ps1
index 586ec6200..a8a5d4351 100644
--- a/tests/scripts/run_wslc_all_tests.ps1
+++ b/tests/scripts/run_wslc_all_tests.ps1
@@ -46,8 +46,13 @@ $ErrorActionPreference = "Stop"
 $RepoRoot = Split-Path -Parent (Split-Path -Parent $PSScriptRoot)
 $TestConfigs = Join-Path $RepoRoot "tests\configs"
 
-# Find binary -- prefer explicit path, then probe target-specific and default dirs.
-$Target = "x86_64-pc-windows-msvc"
+# Find binary -- prefer explicit path, then probe target-specific and default
+# dirs. Use the host arch to determine which target to use. 
+$Target = if ($env:PROCESSOR_ARCHITECTURE -eq 'ARM64') {
+    'aarch64-pc-windows-msvc'
+} else {
+    'x86_64-pc-windows-msvc'
+}
 $Profile = if ($Debug) { "debug" } else { "release" }
 
 if ($WxcExecPath) {
@@ -64,7 +69,7 @@ if (-not $WxcExec -or -not (Test-Path $WxcExec)) {
     Write-Host "ERROR: wxc-exec.exe not found." -ForegroundColor Red
     Write-Host "Searched:" -ForegroundColor Yellow
     foreach ($p in $CandidatePaths) { Write-Host "  - $p" -ForegroundColor Yellow }
-    Write-Host "Build with: cargo build --features wslc $(if (-not $Debug) { '--release ' })--target $Target" -ForegroundColor Yellow
+    Write-Host "Build with: cargo build --features wslc $(if (-not $Debug) { '--release ' })--target $HostTarget" -ForegroundColor Yellow
     Write-Host "Or pass -WxcExecPath explicitly." -ForegroundColor Yellow
     exit 1
 }
diff --git a/tests/scripts/run_wslc_denied_masking_test.ps1 b/tests/scripts/run_wslc_denied_masking_test.ps1
index 8ff54ef74..70c3954e9 100644
--- a/tests/scripts/run_wslc_denied_masking_test.ps1
+++ b/tests/scripts/run_wslc_denied_masking_test.ps1
@@ -30,8 +30,13 @@ $ErrorActionPreference = "Stop"
 $RepoRoot = Split-Path -Parent (Split-Path -Parent $PSScriptRoot)
 $ConfigPath = Join-Path $RepoRoot "tests\configs\wslc_denied_masking.json"
 
-# Resolve the binary: explicit path, then target-specific and default dirs.
-$Target = "x86_64-pc-windows-msvc"
+# Find binary -- prefer explicit path, then probe target-specific and default
+# dirs. Use the host arch to determine which target to use. 
+$Target = if ($env:PROCESSOR_ARCHITECTURE -eq 'ARM64') {
+    'aarch64-pc-windows-msvc'
+} else {
+    'x86_64-pc-windows-msvc'
+}
 $Profile = if ($Debug) { "debug" } else { "release" }
 if ($WxcExecPath) {
     $WxcExec = $WxcExecPath
diff --git a/tests/scripts/run_wslc_dotdot_alias_test.ps1 b/tests/scripts/run_wslc_dotdot_alias_test.ps1
index de3aa3a0e..83e5286bb 100644
--- a/tests/scripts/run_wslc_dotdot_alias_test.ps1
+++ b/tests/scripts/run_wslc_dotdot_alias_test.ps1
@@ -32,8 +32,13 @@ $ErrorActionPreference = "Stop"
 $RepoRoot = Split-Path -Parent (Split-Path -Parent $PSScriptRoot)
 $ConfigPath = Join-Path $RepoRoot "tests\configs\wslc_denied_dotdot_alias.json"
 
-# Resolve the binary: explicit path, then target-specific and default dirs.
-$Target = "x86_64-pc-windows-msvc"
+# Find binary -- prefer explicit path, then probe target-specific and default
+# dirs. Use the host arch to determine which target to use. 
+$Target = if ($env:PROCESSOR_ARCHITECTURE -eq 'ARM64') {
+    'aarch64-pc-windows-msvc'
+} else {
+    'x86_64-pc-windows-msvc'
+}
 $Profile = if ($Debug) { "debug" } else { "release" }
 if ($WxcExecPath) {
     $WxcExec = $WxcExecPath
diff --git a/tests/scripts/run_wslc_most_specific_test.ps1 b/tests/scripts/run_wslc_most_specific_test.ps1
index 9fec04434..4b8618403 100644
--- a/tests/scripts/run_wslc_most_specific_test.ps1
+++ b/tests/scripts/run_wslc_most_specific_test.ps1
@@ -27,8 +27,13 @@ $ErrorActionPreference = "Stop"
 $RepoRoot = Split-Path -Parent (Split-Path -Parent $PSScriptRoot)
 $ConfigPath = Join-Path $RepoRoot "tests\configs\wslc_most_specific_denied_parent.json"
 
-# Resolve the binary: explicit path, then target-specific and default dirs.
-$Target = "x86_64-pc-windows-msvc"
+# Find binary -- prefer explicit path, then probe target-specific and default
+# dirs. Use the host arch to determine which target to use. 
+$Target = if ($env:PROCESSOR_ARCHITECTURE -eq 'ARM64') {
+    'aarch64-pc-windows-msvc'
+} else {
+    'x86_64-pc-windows-msvc'
+}
 $Profile = if ($Debug) { "debug" } else { "release" }
 if ($WxcExecPath) {
     $WxcExec = $WxcExecPath
diff --git a/tests/scripts/run_wslc_object_test.ps1 b/tests/scripts/run_wslc_object_test.ps1
index b6b909acd..2dab253bb 100644
--- a/tests/scripts/run_wslc_object_test.ps1
+++ b/tests/scripts/run_wslc_object_test.ps1
@@ -28,8 +28,13 @@ $ErrorActionPreference = "Stop"
 $RepoRoot = Split-Path -Parent (Split-Path -Parent $PSScriptRoot)
 $ConfigPath = Join-Path $RepoRoot "tests\configs\wslc_filesystem_object.json"
 
-# Resolve the binary: explicit path, then target-specific and default dirs.
-$Target = "x86_64-pc-windows-msvc"
+# Find binary -- prefer explicit path, then probe target-specific and default
+# dirs. Use the host arch to determine which target to use. 
+$Target = if ($env:PROCESSOR_ARCHITECTURE -eq 'ARM64') {
+    'aarch64-pc-windows-msvc'
+} else {
+    'x86_64-pc-windows-msvc'
+}
 $Profile = if ($Debug) { "debug" } else { "release" }
 if ($WxcExecPath) {
     $WxcExec = $WxcExecPath
diff --git a/tests/scripts/run_wslc_proxy_test.ps1 b/tests/scripts/run_wslc_proxy_test.ps1
index d7f9ffbf0..92b6282c4 100644
--- a/tests/scripts/run_wslc_proxy_test.ps1
+++ b/tests/scripts/run_wslc_proxy_test.ps1
@@ -37,8 +37,13 @@ $ErrorActionPreference = "Stop"
 $RepoRoot = Split-Path -Parent (Split-Path -Parent $PSScriptRoot)
 $ConfigPath = Join-Path $RepoRoot "tests\configs\wslc_network_proxy.json"
 
-# Resolve the binary: explicit path, then target-specific and default dirs.
-$Target = "x86_64-pc-windows-msvc"
+# Find binary -- prefer explicit path, then probe target-specific and default
+# dirs. Use the host arch to determine which target to use. 
+$Target = if ($env:PROCESSOR_ARCHITECTURE -eq 'ARM64') {
+    'aarch64-pc-windows-msvc'
+} else {
+    'x86_64-pc-windows-msvc'
+}
 $Profile = if ($Debug) { "debug" } else { "release" }
 if ($WxcExecPath) {
     $WxcExec = $WxcExecPath
diff --git a/tests/scripts/run_wslc_state_aware_tests.ps1 b/tests/scripts/run_wslc_state_aware_tests.ps1
index 6b95515d1..f1642b2bb 100644
--- a/tests/scripts/run_wslc_state_aware_tests.ps1
+++ b/tests/scripts/run_wslc_state_aware_tests.ps1
@@ -66,7 +66,13 @@ $RepoRoot = Split-Path -Parent (Split-Path -Parent $PSScriptRoot)
 
 # ---------------- Locate wxc-exec.exe + daemon ----------------
 
-$Target = "x86_64-pc-windows-msvc"
+# Find binary -- prefer explicit path, then probe target-specific and default
+# dirs. Use the host arch to determine which target to use. 
+$Target = if ($env:PROCESSOR_ARCHITECTURE -eq 'ARM64') {
+    'aarch64-pc-windows-msvc'
+} else {
+    'x86_64-pc-windows-msvc'
+}
 $Prof = if ($Debug) { "debug" } else { "release" }
 
 if ($WxcExecPath) {

From cef5e60eec6cfc9c0a0f338229fea61d445ccb67 Mon Sep 17 00:00:00 2001
From: Elliot Michlin <31219104+theelliotm@users.noreply.github.com>
Date: Mon, 21 Sep 2026 12:12:00 -0700
Subject: [PATCH 2/3] Correct documentation

---
 docs/wsl/wsl-container-getting-started.md    | 5 +++++
 docs/wsl/wslc-sdk-bindings.md                | 2 +-
 tests/scripts/run_wslc_all_tests.ps1         | 4 ++--
 tests/scripts/run_wslc_state_aware_tests.ps1 | 2 +-
 4 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/docs/wsl/wsl-container-getting-started.md b/docs/wsl/wsl-container-getting-started.md
index a4a1943c2..8fca81e32 100644
--- a/docs/wsl/wsl-container-getting-started.md
+++ b/docs/wsl/wsl-container-getting-started.md
@@ -101,6 +101,11 @@ Verify the binary starts without errors:
 .\src\target\x86_64-pc-windows-msvc\release\wxc-exec.exe --help
 ```
 
+> **Note:** paths in this guide use the x64 target directory. On an ARM64 host
+> `build.bat` targets `aarch64-pc-windows-msvc`, so substitute that directory.
+> The WSLC scripts under `scripts\` and `tests\scripts\` pick the host-arch
+> directory themselves.
+
 > **Note:** `wxc-exec.exe` does **not** require `wslcsdk.dll` at startup. The
 > DLL is loaded at runtime only when the WSLC backend is invoked. All other
 > backends (Process Container, Windows Sandbox) work without it.
diff --git a/docs/wsl/wslc-sdk-bindings.md b/docs/wsl/wslc-sdk-bindings.md
index 9858cc5c6..a7c375182 100644
--- a/docs/wsl/wslc-sdk-bindings.md
+++ b/docs/wsl/wslc-sdk-bindings.md
@@ -108,7 +108,7 @@ match the pinned SDK.
    staged next to `wxc-exec.exe`, then:
 
    ```powershell
-   cargo build -p wxc --features wslc --release --target x86_64-pc-windows-msvc
+   cargo build -p wxc --features wslc --release --target x86_64-pc-windows-msvc  # aarch64-pc-windows-msvc on ARM64
    .\tests\scripts\run_wslc_all_tests.ps1
    ```
 
diff --git a/tests/scripts/run_wslc_all_tests.ps1 b/tests/scripts/run_wslc_all_tests.ps1
index a8a5d4351..db29d7a29 100644
--- a/tests/scripts/run_wslc_all_tests.ps1
+++ b/tests/scripts/run_wslc_all_tests.ps1
@@ -47,7 +47,7 @@ $RepoRoot = Split-Path -Parent (Split-Path -Parent $PSScriptRoot)
 $TestConfigs = Join-Path $RepoRoot "tests\configs"
 
 # Find binary -- prefer explicit path, then probe target-specific and default
-# dirs. Use the host arch to determine which target to use. 
+# dirs. Use the host arch to determine which target to use.
 $Target = if ($env:PROCESSOR_ARCHITECTURE -eq 'ARM64') {
     'aarch64-pc-windows-msvc'
 } else {
@@ -69,7 +69,7 @@ if (-not $WxcExec -or -not (Test-Path $WxcExec)) {
     Write-Host "ERROR: wxc-exec.exe not found." -ForegroundColor Red
     Write-Host "Searched:" -ForegroundColor Yellow
     foreach ($p in $CandidatePaths) { Write-Host "  - $p" -ForegroundColor Yellow }
-    Write-Host "Build with: cargo build --features wslc $(if (-not $Debug) { '--release ' })--target $HostTarget" -ForegroundColor Yellow
+    Write-Host "Build with: cargo build --features wslc $(if (-not $Debug) { '--release ' })--target $Target" -ForegroundColor Yellow
     Write-Host "Or pass -WxcExecPath explicitly." -ForegroundColor Yellow
     exit 1
 }
diff --git a/tests/scripts/run_wslc_state_aware_tests.ps1 b/tests/scripts/run_wslc_state_aware_tests.ps1
index f1642b2bb..965f49ecd 100644
--- a/tests/scripts/run_wslc_state_aware_tests.ps1
+++ b/tests/scripts/run_wslc_state_aware_tests.ps1
@@ -37,7 +37,7 @@
     provision so the spawned daemon inherits them.
 
 .PARAMETER WxcExecPath
-    Path to wxc-exec.exe. Default probes the x64 target release/debug dirs.
+    Path to wxc-exec.exe. Default probes the host-arch target release/debug dirs.
 
 .PARAMETER ConfigDir
     Directory holding the state-aware request fixtures. Defaults to

From 24f0049faaac06e927b1d2281d3352a3f4e4f50b Mon Sep 17 00:00:00 2001
From: Elliot Michlin <31219104+theelliotm@users.noreply.github.com>
Date: Mon, 21 Sep 2026 16:49:12 -0700
Subject: [PATCH 3/3] WSLC in CI no longer blocks ARM either

---
 scripts/ci/run_backend_validation_tests.ps1 | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/scripts/ci/run_backend_validation_tests.ps1 b/scripts/ci/run_backend_validation_tests.ps1
index 66caf27d3..830f31ad1 100644
--- a/scripts/ci/run_backend_validation_tests.ps1
+++ b/scripts/ci/run_backend_validation_tests.ps1
@@ -217,10 +217,6 @@ switch ($Backend) {
         }
     }
     'wslc' {
-        # The current WSLC helper hardcodes the x64 target when locating assets.
-        if ($Architecture -ne 'x64') {
-            throw 'The existing WSLC test harness is not architecture-portable yet.'
-        }
         Invoke-TestScript -Path (Join-Path $testScriptRoot 'run_wslc_all_tests.ps1') -Arguments @{
             WxcExecPath = $wxc
         }