This is a note to let you know that I've just added the patch titled x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-speculation-mmio-add-sysfs-reporting-for-processor-mmio-stale-data.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Tue Jun 14 07:10:28 PM CEST 2022 From: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx> Date: Thu, 19 May 2022 20:32:13 -0700 Subject: x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data From: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- Documentation/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(+) --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -361,6 +361,7 @@ What: /sys/devices/system/cpu/vulnerabi /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@xxxxxxxxxxxxxxx> Description: Information about CPU vulnerabilities --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1809,6 +1809,20 @@ static ssize_t tsx_async_abort_show_stat 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)) @@ -1906,6 +1920,9 @@ static ssize_t cpu_show_common(struct de case X86_BUG_SRBDS: return srbds_show_state(buf); + case X86_BUG_MMIO_STALE_DATA: + return mmio_stale_data_show_state(buf); + default: break; } @@ -1957,4 +1974,9 @@ ssize_t cpu_show_srbds(struct device *de { 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 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -556,6 +556,12 @@ ssize_t __weak cpu_show_srbds(struct dev return sprintf(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); @@ -565,6 +571,7 @@ static DEVICE_ATTR(mds, 0444, cpu_show_m 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, @@ -576,6 +583,7 @@ static struct attribute *cpu_root_vulner &dev_attr_tsx_async_abort.attr, &dev_attr_itlb_multihit.attr, &dev_attr_srbds.attr, + &dev_attr_mmio_stale_data.attr, NULL }; --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -62,6 +62,9 @@ extern ssize_t cpu_show_tsx_async_abort( 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, Patches currently in stable-queue which might be from pawan.kumar.gupta@xxxxxxxxxxxxxxx are queue-4.9/x86-speculation-add-a-common-function-for-md_clear-mitigation-update.patch queue-4.9/x86-speculation-mmio-reuse-srbds-mitigation-for-sbds.patch queue-4.9/x86-speculation-mmio-add-sysfs-reporting-for-processor-mmio-stale-data.patch queue-4.9/x86-speculation-srbds-update-srbds-mitigation-selection.patch queue-4.9/x86-speculation-mmio-enable-cpu-fill-buffer-clearing-on-idle.patch queue-4.9/x86-bugs-group-mds-taa-processor-mmio-stale-data-mitigations.patch queue-4.9/x86-speculation-mmio-enumerate-processor-mmio-stale-data-bug.patch queue-4.9/documentation-add-documentation-for-processor-mmio-stale-data.patch queue-4.9/kvm-x86-speculation-disable-fill-buffer-clear-within-guests.patch queue-4.9/x86-speculation-mmio-add-mitigation-for-processor-mmio-stale-data.patch