From 2b1b6f0a4d5cd950b3df76454f8cc0da1a6ef316 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=89=A7=E7=80=AC=E7=B4=85=E8=8E=89=E6=A0=96?=
 <MakiseKurisu@users.noreply.github.com>
Date: Mon, 25 Oct 2021 16:48:46 +0800
Subject: [PATCH] Implement CPU pinning

While this can be done by [3rd party script](https://github.com/ayufan/pve-helpers/), running on non SMP system requires this to be set before KVM was even started, otherwise you get error [qemu kvm_arm_vcpu_init failed: Invalid argument"](https://forum.armbian.com/topic/16830-virtualization-support/). This is a [known limitation](https://www.mail-archive.com/qemu-devel@nongnu.org/msg755010.html) of QEMU.
---
 PVE/QemuServer.pm | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 975cca3..f17bf06 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -686,6 +686,15 @@ EODESCR
 	description => "Configure a VirtIO-based Random Number Generator.",
 	optional => 1,
     },
+    cpu_taskset => {
+	optional => 1,
+	type => 'string',
+	description => "CPU pinning config.",
+	verbose_description => "When specified VM will be launched with `cpuset -c {cpu_taskset} kvm ...`\n"
+	    ."No argument test is performed so please make sure the value matches VM cpu total thread count.\n"
+	    ."This is required when VM is sensitive to host context switching (e.g. gaming),"
+	    ." or when host is not SMP so VM thread could be switched to a different CPU architecture (e.g. big.LITTLE for ARM).",
+    },
 };
 
 my $cicustom_fmt = {
@@ -3219,6 +3228,10 @@ sub config_to_command {
     my $cpuunits = defined($conf->{cpuunits}) ?
             $conf->{cpuunits} : $defaults->{cpuunits};
 
+    if (defined($conf->{cpu_taskset})) {
+        push @$cmd, 'taskset', '-c', $conf->{cpu_taskset};
+    }
+
     push @$cmd, $kvm_binary;
 
     push @$cmd, '-id', $vmid;