From 3d1905e3f5d8cf79928f02300a007cb492369b97 Mon Sep 17 00:00:00 2001
From: Aaron Andersen <aaron@fosslib.net>
Date: Mon, 22 Jul 2019 13:22:16 -0400
Subject: [PATCH] linux/kernel: enable automatic cpu hotplug support

---
 pkgs/os-specific/linux/kernel/common-config.nix | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pkgs/os-specific/linux/kernel/common-config.nix b/pkgs/os-specific/linux/kernel/common-config.nix
index 855f854b111d..b392dc853d35 100644
--- a/pkgs/os-specific/linux/kernel/common-config.nix
+++ b/pkgs/os-specific/linux/kernel/common-config.nix
@@ -699,11 +699,13 @@ let
       PREEMPT_VOLUNTARY = yes;
 
     } // optionalAttrs (stdenv.hostPlatform.system == "x86_64-linux" || stdenv.hostPlatform.system == "aarch64-linux") {
-      # Enable memory hotplug support
-      # Allows you to dynamically add & remove memory to a VM client running NixOS without requiring a reboot
+      # Enable CPU/memory hotplug support
+      # Allows you to dynamically add & remove CPUs/memory to a VM client running NixOS without requiring a reboot
+      ACPI_HOTPLUG_CPU = yes;
       ACPI_HOTPLUG_MEMORY = yes;
       MEMORY_HOTPLUG = yes;
       MEMORY_HOTREMOVE = yes;
+      HOTPLUG_CPU = yes;
       MIGRATION = yes;
       SPARSEMEM = yes;