linux/Documentation
Waiman Long 64870ed1b1 x86/speculation: Fix incorrect MDS/TAA mitigation status
For MDS vulnerable processors with TSX support, enabling either MDS or
TAA mitigations will enable the use of VERW to flush internal processor
buffers at the right code path. IOW, they are either both mitigated
or both not. However, if the command line options are inconsistent,
the vulnerabilites sysfs files may not report the mitigation status
correctly.

For example, with only the "mds=off" option:

  vulnerabilities/mds:Vulnerable; SMT vulnerable
  vulnerabilities/tsx_async_abort:Mitigation: Clear CPU buffers; SMT vulnerable

The mds vulnerabilities file has wrong status in this case. Similarly,
the taa vulnerability file will be wrong with mds mitigation on, but
taa off.

Change taa_select_mitigation() to sync up the two mitigation status
and have them turned off if both "mds=off" and "tsx_async_abort=off"
are present.

Update documentation to emphasize the fact that both "mds=off" and
"tsx_async_abort=off" have to be specified together for processors that
are affected by both TAA and MDS to be effective.

 [ bp: Massage and add kernel-parameters.txt change too. ]

Fixes: 1b42f01741 ("x86/speculation/taa: Add mitigation for TSX Async Abort")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-doc@vger.kernel.org
Cc: Mark Gross <mgross@linux.intel.com>
Cc: <stable@vger.kernel.org>
Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191115161445.30809-2-longman@redhat.com
2019-11-16 13:17:49 +01:00
..
ABI x86/bugs: Add ITLB_MULTIHIT bug infrastructure 2019-11-04 12:22:01 +01:00
accounting docs: add some documentation dirs to the driver-api book 2019-07-15 11:03:02 -03:00
admin-guide x86/speculation: Fix incorrect MDS/TAA mitigation status 2019-11-16 13:17:49 +01:00
arm Documentation/arm/samsung-s3c24xx: Remove stray U+FEFF character to fix title 2019-08-12 15:25:32 -06:00
arm64 arm64: apply ARM64_ERRATUM_843419 workaround for Brahma-B53 core 2019-11-01 10:47:37 +00:00
block docs: block: null_blk: enhance document style 2019-09-11 16:04:22 -06:00
bpf bpf/flow_dissector: document flags 2019-07-25 18:00:41 -07:00
cdrom docs: add some directories to the main documentation index 2019-07-15 11:03:03 -03:00
core-api Modules fixes for v5.4-rc3 2019-10-11 10:19:24 -07:00
cpu-freq Documentation: cpufreq: Update policy notifier documentation 2019-09-02 22:44:05 +02:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-09-18 12:11:14 -07:00
dev-tools mm, page_owner: decouple freeing stack trace from debug_pagealloc 2019-10-14 15:04:00 -07:00
devicetree ARM: SoC fixes 2019-10-25 16:00:47 -04:00
doc-guide docs: remove extra conf.py files 2019-07-17 06:57:52 -03:00
driver-api This is the bulk of pin control changes for the v5.4 kernel 2019-09-19 14:19:33 -07:00
EDID docs: driver-api: add a series of orphaned documents 2019-07-15 11:03:02 -03:00
fault-injection docs: add some directories to the main documentation index 2019-07-15 11:03:03 -03:00
fb docs conversion for v5.3-rc1 2019-07-16 12:21:41 -07:00
features It's a somewhat calmer cycle for docs this time, as the churn of the mass 2019-09-17 16:22:26 -07:00
filesystems add virtio-fs 2019-09-27 15:54:24 -07:00
firmware_class
firmware-guide Documentation: ACPI: DSD: Convert LED documentation to ReST 2019-08-20 23:53:46 +02:00
fpga Documentation: fpga: dfl: add descriptions for virtualization and new interfaces. 2019-09-03 19:35:42 -07:00
gpu Merge drm/drm-next into drm-intel-next-queued 2019-08-22 00:10:36 -07:00
hid docs: add some documentation dirs to the driver-api book 2019-07-15 11:03:02 -03:00
hwmon hwmon: docs: Extend inspur-ipsps1 title underline 2019-10-07 05:56:57 -07:00
i2c docs: i2c: convert to ReST and add to driver-api bookset 2019-07-31 13:25:27 -06:00
ia64 docs: add SPDX tags to new index files 2019-07-15 11:03:03 -03:00
ide docs: add some directories to the main documentation index 2019-07-15 11:03:03 -03:00
iio docs: add some documentation dirs to the driver-api book 2019-07-15 11:03:02 -03:00
infiniband Documentation/infiniband: update name of some functions 2019-09-13 16:55:55 -03:00
input Input: docs: fix spelling mistake "potocol" -> "protocol" 2019-08-06 11:24:49 -06:00
ioctl fs-verity: add UAPI header 2019-07-28 16:59:16 -07:00
isdn docs: isdn: convert to ReST and add to kAPI bookset 2019-07-31 13:30:25 -06:00
kbuild Modules fixes for v5.4-rc3 2019-10-11 10:19:24 -07:00
kernel-hacking docs: Add documentation for Symbol Namespaces 2019-09-10 10:30:49 +02:00
leds leds: core: Add support for composing LED class device names 2019-07-25 20:07:52 +02:00
livepatch docs: add some directories to the main documentation index 2019-07-15 11:03:03 -03:00
locking doc🔒 remove reference to clever use of read-write lock 2019-09-14 01:53:27 -06:00
m68k docs: README.buddha: convert to ReST and add to m68k book 2019-07-31 13:30:10 -06:00
maintainer docs: Fix typo on pull requests guide 2019-08-12 15:14:14 -06:00
media drm main pull for 5.4-rc1 2019-09-19 16:24:24 -07:00
mic docs: driver-api: add remaining converted dirs to it 2019-07-15 11:03:03 -03:00
mips Main MIPS changes for v5.4: 2019-09-22 09:30:30 -07:00
misc-devices Docs: misc: xilinx_sdfec: Add documentation 2019-08-15 17:54:38 +02:00
netlabel docs: add some directories to the main documentation index 2019-07-15 11:03:03 -03:00
networking Documentation: TLS: Add missing counter description 2019-11-05 18:34:06 -08:00
nios2 docs: nios2: add it to the main Documentation body 2019-07-31 13:31:51 -06:00
openrisc docs: openrisc: convert to ReST and add to documentation body 2019-07-31 13:30:20 -06:00
parisc docs: parisc: convert to ReST and add to documentation body 2019-07-31 13:30:15 -06:00
PCI Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-08-27 14:23:31 -07:00
pcmcia docs: add some directories to the main documentation index 2019-07-15 11:03:03 -03:00
power Merge branches 'pm-opp', 'pm-qos', 'acpi-pm', 'pm-domains' and 'pm-tools' 2019-09-17 09:49:19 +02:00
powerpc docs: powerpc: Add missing documentation reference 2019-09-17 23:59:34 +10:00
process Documentation/process: Add fallthrough pseudo-keyword 2019-10-11 09:26:05 -07:00
RCU Merge branches 'consolidate.2019.08.01b', 'fixes.2019.08.12a', 'lists.2019.08.13a' and 'torture.2019.08.01b' into HEAD 2019-08-13 14:30:30 -07:00
riscv It's a somewhat calmer cycle for docs this time, as the churn of the mass 2019-09-17 16:22:26 -07:00
s390 Documentation/s390: remove outdated debugging390 documentation 2019-08-21 12:41:43 +02:00
scheduler sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices 2019-08-08 09:09:30 +02:00
scsi scsi: ufs: Documentation: Announce ufs-tool v1.0 2019-06-26 22:47:51 -04:00
security Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2019-09-27 19:37:27 -07:00
sh docs: remove extra conf.py files 2019-07-17 06:57:52 -03:00
sound sound updates for 5.4 2019-09-17 17:43:33 -07:00
sparc docs: add arch doc directories to the index 2019-07-15 11:03:01 -03:00
sphinx Documentation: sphinx: Don't parse socket() as identifier reference 2019-08-12 14:55:30 -06:00
sphinx-static
spi spi: docs: convert to ReST and add it to the kABI bookset 2019-07-31 14:13:13 -06:00
target docs: add some directories to the main documentation index 2019-07-15 11:03:03 -03:00
timers docs: add some directories to the main documentation index 2019-07-15 11:03:03 -03:00
trace Tracing updates: 2019-09-20 11:19:48 -07:00
translations doc: arm64: fix grammar dtb placed in no attributes region 2019-09-06 08:44:34 -06:00
usb USB: rio500: Remove Rio 500 kernel driver 2019-10-04 10:53:36 +02:00
userspace-api docs: remove extra conf.py files 2019-07-17 06:57:52 -03:00
virt KVM/Hyper-V: Add new KVM capability KVM_CAP_HYPERV_DIRECT_TLBFLUSH 2019-09-24 13:37:13 +02:00
virtual cpuidle: add haltpoll governor 2019-07-30 17:27:37 +02:00
vm mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
w1 docs: w1: convert to ReST and add to the kAPI group of docs 2019-07-31 14:16:17 -06:00
watchdog linux-watchdog 5.4-rc1 tag 2019-09-27 11:17:38 -07:00
x86 x86/speculation/taa: Add documentation for TSX Async Abort 2019-10-28 08:37:00 +01:00
xtensa docs: add arch doc directories to the index 2019-07-15 11:03:01 -03:00
.gitignore
atomic_bitops.txt docs: atomic_bitops.txt: add a title for this document 2019-04-11 12:37:02 -06:00
atomic_t.txt Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 16:12:03 -07:00
bus-virt-phys-mapping.txt
Changes
CodingStyle
conf.py docs: conf.py: only use CJK if the font is available 2019-07-17 06:57:51 -03:00
COPYING-logo docs: logo.txt: rename it to COPYING-logo 2019-07-15 09:20:27 -03:00
crc32.txt
debugging-modules.txt
debugging-via-ohci1394.txt
digsig.txt
DMA-API-HOWTO.txt docs: DMA-API-HOWTO.txt: fix an unmarked code block 2019-07-15 09:20:24 -03:00
DMA-API.txt dma-mapping: remove dma_release_declared_memory 2019-09-04 11:13:19 +02:00
DMA-attributes.txt
DMA-ISA-LPC.txt
docutils.conf doc-rst: Add missing newline at end of file 2019-06-20 14:16:56 -06:00
dontdiff kbuild: create *.mod with full directory path and remove MODVERDIR 2019-07-18 02:19:31 +09:00
futex-requeue-pi.txt
hwspinlock.txt hwspinlock: add the 'in_atomic' API 2019-06-29 21:08:14 -07:00
index.rst Main MIPS changes for v5.4: 2019-09-22 09:30:30 -07:00
io_ordering.txt
io-mapping.txt
IPMI.txt
IRQ-affinity.txt
IRQ-domain.txt
IRQ.txt
irqflags-tracing.txt
Kconfig docs: Kbuild/Makefile: allow check for missing docs at build time 2019-06-07 11:33:16 -06:00
kobject.txt
kprobes.txt Merge branch 'parisc-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux 2019-05-07 19:34:17 -07:00
kref.txt
logo.gif
lzo.txt lib/lzo: fix bugs for very short or empty input 2019-04-05 16:02:30 -10:00
mailbox.txt
Makefile docs: Kbuild/Makefile: allow check for missing docs at build time 2019-06-07 11:33:16 -06:00
memory-barriers.txt docs: fix broken doc references due to renames 2019-07-17 06:57:51 -03:00
nommu-mmap.txt
padata.txt padata: allocate workqueue internally 2019-09-13 21:15:39 +10:00
percpu-rw-semaphore.txt
pi-futex.txt docs: locking: convert docs to ReST and rename to *.rst 2019-07-15 08:53:27 -03:00
preempt-locking.txt x86/fpu: Remove fpu__restore() 2019-04-09 19:27:42 +02:00
rbtree.txt docs: rbtree.txt: fix Sphinx build warnings 2019-07-15 09:20:24 -03:00
remoteproc.txt remoteproc: add vendor resources handling 2019-06-29 12:02:17 -07:00
robust-futex-ABI.txt
robust-futexes.txt futex: Update comments and docs about return values of arch futex code 2019-04-26 13:57:55 +01:00
rpmsg.txt
speculation.txt docs: speculation.txt: mark example blocks as such 2019-04-11 12:37:03 -06:00
static-keys.txt
SubmittingPatches
tee.txt Documentation: tee: Grammar s/the its/its/ 2019-06-07 11:23:38 -06:00
this_cpu_ops.txt
unaligned-memory-access.txt docs: unaligned-memory-access.txt: use a lowercase title 2019-04-11 12:37:03 -06:00
xz.txt