diff mbox series

[SRU,OEM-5.14,07/11] x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data

Message ID 20220615121725.3995677-8-cascardo@canonical.com
State New
Headers show
Series MMIO Stale Data mitigations | expand

Commit Message

Thadeu Lima de Souza Cascardo June 15, 2022, 12:17 p.m. UTC 
From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>

commit 8d50cdf8b8341770bc6367bce40c0c1bb0e1d5b3 upstream

Add the sysfs reporting file for Processor MMIO Stale Data
vulnerability. It exposes the vulnerability and mitigation state similar
to the existing files for the other hardware vulnerabilities.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
CVE-2022-21166
CVE-2022-21123
CVE-2022-21125
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
---
 .../ABI/testing/sysfs-devices-system-cpu      |  1 +
 arch/x86/kernel/cpu/bugs.c                    | 22 +++++++++++++++++++
 drivers/base/cpu.c                            |  8 +++++++
 include/linux/cpu.h                           |  3 +++
 4 files changed, 34 insertions(+)
diff mbox series

Patch

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 160b10c029c0..79234aaafa57 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -511,6 +511,7 @@  What:		/sys/devices/system/cpu/vulnerabilities
 		/sys/devices/system/cpu/vulnerabilities/srbds
 		/sys/devices/system/cpu/vulnerabilities/tsx_async_abort
 		/sys/devices/system/cpu/vulnerabilities/itlb_multihit
+		/sys/devices/system/cpu/vulnerabilities/mmio_stale_data
 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 a39019760d9e..6108e5a294ea 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1832,6 +1832,20 @@  static ssize_t tsx_async_abort_show_state(char *buf)
 		       sched_smt_active() ? "vulnerable" : "disabled");
 }
 
+static ssize_t mmio_stale_data_show_state(char *buf)
+{
+	if (mmio_mitigation == MMIO_MITIGATION_OFF)
+		return sysfs_emit(buf, "%s\n", mmio_strings[mmio_mitigation]);
+
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
+		return sysfs_emit(buf, "%s; SMT Host state unknown\n",
+				  mmio_strings[mmio_mitigation]);
+	}
+
+	return sysfs_emit(buf, "%s; SMT %s\n", mmio_strings[mmio_mitigation],
+			  sched_smt_active() ? "vulnerable" : "disabled");
+}
+
 static char *stibp_state(void)
 {
 	if (spectre_v2_in_eibrs_mode(spectre_v2_enabled))
@@ -1932,6 +1946,9 @@  static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
 	case X86_BUG_SRBDS:
 		return srbds_show_state(buf);
 
+	case X86_BUG_MMIO_STALE_DATA:
+		return mmio_stale_data_show_state(buf);
+
 	default:
 		break;
 	}
@@ -1983,4 +2000,9 @@  ssize_t cpu_show_srbds(struct device *dev, struct device_attribute *attr, char *
 {
 	return cpu_show_common(dev, attr, buf, X86_BUG_SRBDS);
 }
+
+ssize_t cpu_show_mmio_stale_data(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return cpu_show_common(dev, attr, buf, X86_BUG_MMIO_STALE_DATA);
+}
 #endif
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 5ef14db97904..a6e7f71d882b 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -564,6 +564,12 @@  ssize_t __weak cpu_show_srbds(struct device *dev,
 	return sysfs_emit(buf, "Not affected\n");
 }
 
+ssize_t __weak cpu_show_mmio_stale_data(struct device *dev,
+					struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(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);
@@ -573,6 +579,7 @@  static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
 static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
 static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
 static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL);
+static DEVICE_ATTR(mmio_stale_data, 0444, cpu_show_mmio_stale_data, NULL);
 
 static struct attribute *cpu_root_vulnerabilities_attrs[] = {
 	&dev_attr_meltdown.attr,
@@ -584,6 +591,7 @@  static struct attribute *cpu_root_vulnerabilities_attrs[] = {
 	&dev_attr_tsx_async_abort.attr,
 	&dev_attr_itlb_multihit.attr,
 	&dev_attr_srbds.attr,
+	&dev_attr_mmio_stale_data.attr,
 	NULL
 };
 
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 94a578a96202..35807c5c8535 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -65,6 +65,9 @@  extern ssize_t cpu_show_tsx_async_abort(struct device *dev,
 extern ssize_t cpu_show_itlb_multihit(struct device *dev,
 				      struct device_attribute *attr, char *buf);
 extern ssize_t cpu_show_srbds(struct device *dev, struct device_attribute *attr, char *buf);
+extern ssize_t cpu_show_mmio_stale_data(struct device *dev,
+					struct device_attribute *attr,
+					char *buf);
 
 extern __printf(4, 5)
 struct device *cpu_device_create(struct device *parent, void *drvdata,