From 0f94acd8fb2486b67fc5931653bd8ed88c5be214 Mon Sep 17 00:00:00 2001
From: Eric Schultz <eric@startuperic.com>
Date: Mon, 10 Feb 2020 04:35:23 -0600
Subject: [PATCH] VMs: enable cpu cache passthrough; AMD + multithreaded

---
 plugins/dynamix.vm.manager/include/libvirt.php | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/plugins/dynamix.vm.manager/include/libvirt.php b/plugins/dynamix.vm.manager/include/libvirt.php
index 80233d5be..e8c07c32b 100644
--- a/plugins/dynamix.vm.manager/include/libvirt.php
+++ b/plugins/dynamix.vm.manager/include/libvirt.php
@@ -321,11 +321,22 @@
 			$intCPUThreadsPerCore = 1;
 
 			$cpumode = '';
+			$cpucache = '';
+			$cpufeatures = '';
 			if (!empty($domain['cpumode']) && $domain['cpumode'] == 'host-passthrough') {
 				$cpumode .= "mode='host-passthrough'";
+				$cpucache = "<cache mode='passthrough'/>";
 
 				// detect if the processor is hyperthreaded:
 				$intCPUThreadsPerCore = max(intval(shell_exec('/usr/bin/lscpu | grep \'Thread(s) per core\' | awk \'{print $4}\'')), 1);
+				
+				// detect if the processor is AMD + multithreaded, and if so, enable topoext cpu feature
+				if ($intCPUThreadsPerCore > 1) {
+					$strCPUInfo = file_get_contents('/proc/cpuinfo');
+					if (strpos($strCPUInfo, 'AuthenticAMD') !== false) {
+						$cpufeatures .= "<feature policy='require' name='topoext'/>";
+					}
+				}
 
 				// even amount of cores assigned and cpu is hyperthreaded: pass that info along to the cpu section below
 				if ($intCPUThreadsPerCore > 1 && ($vcpus % $intCPUThreadsPerCore == 0)) {
@@ -336,6 +347,8 @@
 
 			$cpustr = "<cpu $cpumode>
 							<topology sockets='1' cores='{$intCores}' threads='{$intThreads}'/>
+							$cpucache
+							$cpufeatures
 						</cpu>
 						<vcpu placement='static'>{$vcpus}</vcpu>
 						<cputune>