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x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data

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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>
This commit is contained in:
Pawan Gupta 2022-05-19 20:32:13 -07:00 committed by Borislav Petkov
parent 99a83db5a6
commit 8d50cdf8b8
4 changed files with 34 additions and 0 deletions
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1
Documentation/ABI/testing/sysfs-devices-system-cpu
View File

@ -526,6 +526,7 @@ 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

22
arch/x86/kernel/cpu/bugs.c
View File

@ -1902,6 +1902,20 @@ 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))
@ -2002,6 +2016,9 @@ 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;
}
@ -2053,4 +2070,9 @@ 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

8
drivers/base/cpu.c
View File

@ -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
};

3
include/linux/cpu.h
View File

@ -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,