From db7d3206fd1b7d11b786c9fb105f345f3471e396 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Lesimple?= <speed47_github@speed47.net>
Date: Tue, 14 May 2019 20:30:47 +0200
Subject: [PATCH] feat(mds): add detection of availability of MD_CLEAR
 instruction

---
 spectre-meltdown-checker.sh | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/spectre-meltdown-checker.sh b/spectre-meltdown-checker.sh
index 648aa5b..13b4f6c 100755
--- a/spectre-meltdown-checker.sh
+++ b/spectre-meltdown-checker.sh
@@ -2337,6 +2337,20 @@ check_cpu()
 		pstatus yellow UNKNOWN "is cpuid kernel module available?"
 	fi
 
+	if is_intel; then
+		_info "  * Microarchitecture Data Sampling"
+		_info_nol "    * MD_CLEAR instruction is available: "
+		read_cpuid 0x7 $EDX 10 1 1; ret=$?
+		if [ $ret -eq 0 ]; then
+			#cpuid_md_clear=1
+			pstatus green YES
+		elif [ $ret -eq 2 ]; then
+			pstatus yellow UNKNOWN "is cpuid kernel module available?"
+		else
+			pstatus yellow NO
+		fi
+	fi
+
 	if is_intel; then
 		_info     "  * Enhanced IBRS (IBRS_ALL)"
 		_info_nol "    * CPU indicates ARCH_CAPABILITIES MSR availability: "