From 7320f8360ec24159b4fa6e5cdea124f3308384de Mon Sep 17 00:00:00 2001
From: Danny Canter <danny_canter@apple.com>
Date: Wed, 11 Jun 2025 08:39:39 -0700
Subject: [PATCH] VZVirtualMachineInstance: Adjust silent success behavior of
 nested virt (#88)

Fixes #85

The virtualization bool on LinuxContainer mostly just forwards to
VZVirtualMachineInstance which today would silently take your boolean
and do nothing if the underlying platform doesn't have support for it.
This is (to me) arguably worse than erroring, as it gives the client a
false security that the setting is on, and they should have virt
capabilities in the container/guest now.

This change makes it so that we throw a ContainerizationError for this
case, with a code of .unsupported so it's checkable by a user if they
want more information on the "why".
---
 .../VZVirtualMachineInstance.swift            | 14 +++++++-----
 Sources/Integration/Suite.swift               | 22 +++++++++++++++++--
 Sources/Integration/VMTests.swift             | 13 +++++++++--
 3 files changed, 39 insertions(+), 10 deletions(-)

diff --git a/Sources/Containerization/VZVirtualMachineInstance.swift b/Sources/Containerization/VZVirtualMachineInstance.swift
index a5107ea2..87af204d 100644
--- a/Sources/Containerization/VZVirtualMachineInstance.swift
+++ b/Sources/Containerization/VZVirtualMachineInstance.swift
@@ -294,16 +294,18 @@ extension VZVirtualMachineInstance.Configuration {
             try mount.configure(config: &config)
         }
 
-        #if arch(arm64)
-
         let platform = VZGenericPlatformConfiguration()
-        if VZGenericPlatformConfiguration.isNestedVirtualizationSupported {
-            platform.isNestedVirtualizationEnabled = self.nestedVirtualization
+        // We shouldn't silently succeed if the user asked for virt and their hardware does
+        // not support it.
+        if !VZGenericPlatformConfiguration.isNestedVirtualizationSupported && self.nestedVirtualization {
+            throw ContainerizationError(
+                .unsupported,
+                message: "nested virtualization is not supported on the platform"
+            )
         }
+        platform.isNestedVirtualizationEnabled = self.nestedVirtualization
         config.platform = platform
 
-        #endif
-
         try config.validate()
         return config
     }
diff --git a/Sources/Integration/Suite.swift b/Sources/Integration/Suite.swift
index d7cfb07e..b5760ada 100644
--- a/Sources/Integration/Suite.swift
+++ b/Sources/Integration/Suite.swift
@@ -37,6 +37,14 @@ enum IntegrationError: Swift.Error {
     case noOutput
 }
 
+struct SkipTest: Swift.Error, CustomStringConvertible {
+    let reason: String
+
+    var description: String {
+        reason
+    }
+}
+
 @main
 struct IntegrationSuite: AsyncParsableCommand {
     static let appRoot: URL = {
@@ -209,6 +217,7 @@ struct IntegrationSuite: AsyncParsableCommand {
         ]
 
         var passed = 0
+        var skipped = 0
         for (name, test) in tests {
             do {
                 log.info("test \(name) started...")
@@ -218,15 +227,24 @@ struct IntegrationSuite: AsyncParsableCommand {
                 let lasted = CFAbsoluteTimeGetCurrent() - started
                 log.info("✅ test \(name) complete in \(lasted)s.")
                 passed += 1
+            } catch let err as SkipTest {
+                log.info("⏭️ skipped test: \(err)")
+                skipped += 1
             } catch {
                 log.error("❌ test \(name) failed: \(error)")
             }
         }
 
         let ended = CFAbsoluteTimeGetCurrent() - suiteStarted
-        log.info("\nintegration suite completed in \(ended)s with \(passed)/\(tests.count) passed!")
+        var finishingText = "\n\nIntegration suite completed in \(ended)s with \(passed)/\(tests.count) passed"
+        if skipped > 0 {
+            finishingText += " and \(skipped)/\(tests.count) skipped"
+        }
+        finishingText += "!"
 
-        if passed < tests.count {
+        log.info("\(finishingText)")
+
+        if passed + skipped < tests.count {
             log.error("❌")
             throw ExitCode(1)
         }
diff --git a/Sources/Integration/VMTests.swift b/Sources/Integration/VMTests.swift
index e20013ad..682558b9 100644
--- a/Sources/Integration/VMTests.swift
+++ b/Sources/Integration/VMTests.swift
@@ -17,6 +17,7 @@
 
 import ArgumentParser
 import Containerization
+import ContainerizationError
 import ContainerizationOCI
 import Foundation
 import Logging
@@ -69,8 +70,16 @@ extension IntegrationSuite {
 
         container.virtualization = true
 
-        try await container.create()
-        try await container.start()
+        do {
+            try await container.create()
+            try await container.start()
+        } catch {
+            if let err = error as? ContainerizationError {
+                if err.code == .unsupported {
+                    throw SkipTest(reason: err.message)
+                }
+            }
+        }
 
         let status = try await container.wait()
         try await container.stop()