From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 18 Feb 2019 21:51:43 +0000 (+0100)
Subject: x86/speculation/mds: Add sysfs reporting for MDS
X-Git-Tag: v5.2-rc1~75^2~13
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=8a4b06d391b0a42a373808979b5028f5c84d9c6a;p=tomoyo%2Ftomoyo-test1.git

x86/speculation/mds: Add sysfs reporting for MDS

Add the sysfs reporting file for MDS. It exposes the vulnerability and
mitigation state similar to the existing files for the other speculative
hardware vulnerabilities.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jon Masters <jcm@redhat.com>
Tested-by: Jon Masters <jcm@redhat.com>
---

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 9605dbd4b5b5..2db5c3407fd6 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -484,6 +484,7 @@ What:		/sys/devices/system/cpu/vulnerabilities
 		/sys/devices/system/cpu/vulnerabilities/spectre_v2
 		/sys/devices/system/cpu/vulnerabilities/spec_store_bypass
 		/sys/devices/system/cpu/vulnerabilities/l1tf
+		/sys/devices/system/cpu/vulnerabilities/mds
 Date:		January 2018
 Contact:	Linux kernel mailing list <linux-kernel@vger.kernel.org>
 Description:	Information about CPU vulnerabilities
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index c7b29d200d27..7ab16a6ed064 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1172,6 +1172,22 @@ static ssize_t l1tf_show_state(char *buf)
 }
 #endif
 
+static ssize_t mds_show_state(char *buf)
+{
+	if (!hypervisor_is_type(X86_HYPER_NATIVE)) {
+		return sprintf(buf, "%s; SMT Host state unknown\n",
+			       mds_strings[mds_mitigation]);
+	}
+
+	if (boot_cpu_has(X86_BUG_MSBDS_ONLY)) {
+		return sprintf(buf, "%s; SMT %s\n", mds_strings[mds_mitigation],
+			       sched_smt_active() ? "mitigated" : "disabled");
+	}
+
+	return sprintf(buf, "%s; SMT %s\n", mds_strings[mds_mitigation],
+		       sched_smt_active() ? "vulnerable" : "disabled");
+}
+
 static char *stibp_state(void)
 {
 	if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)
@@ -1238,6 +1254,10 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
 		if (boot_cpu_has(X86_FEATURE_L1TF_PTEINV))
 			return l1tf_show_state(buf);
 		break;
+
+	case X86_BUG_MDS:
+		return mds_show_state(buf);
+
 	default:
 		break;
 	}
@@ -1269,4 +1289,9 @@ ssize_t cpu_show_l1tf(struct device *dev, struct device_attribute *attr, char *b
 {
 	return cpu_show_common(dev, attr, buf, X86_BUG_L1TF);
 }
+
+ssize_t cpu_show_mds(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return cpu_show_common(dev, attr, buf, X86_BUG_MDS);
+}
 #endif
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index eb9443d5bae1..2fd6ca1021c2 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -546,11 +546,18 @@ ssize_t __weak cpu_show_l1tf(struct device *dev,
 	return sprintf(buf, "Not affected\n");
 }
 
+ssize_t __weak cpu_show_mds(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "Not affected\n");
+}
+
 static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
 static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
 static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
 static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
 static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL);
+static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
 
 static struct attribute *cpu_root_vulnerabilities_attrs[] = {
 	&dev_attr_meltdown.attr,
@@ -558,6 +565,7 @@ static struct attribute *cpu_root_vulnerabilities_attrs[] = {
 	&dev_attr_spectre_v2.attr,
 	&dev_attr_spec_store_bypass.attr,
 	&dev_attr_l1tf.attr,
+	&dev_attr_mds.attr,
 	NULL
 };
 
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 5041357d0297..3c87ad888ed3 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -57,6 +57,8 @@ extern ssize_t cpu_show_spec_store_bypass(struct device *dev,
 					  struct device_attribute *attr, char *buf);
 extern ssize_t cpu_show_l1tf(struct device *dev,
 			     struct device_attribute *attr, char *buf);
+extern ssize_t cpu_show_mds(struct device *dev,
+			    struct device_attribute *attr, char *buf);
 
 extern __printf(4, 5)
 struct device *cpu_device_create(struct device *parent, void *drvdata,