Michael S. Tsirkin 668fffa3f8 kvm: better MWAIT emulation for guests ... Guests that are heavy on futexes end up IPI'ing each other a lot. That can lead to significant slowdowns and latency increase for those guests when running within KVM. If only a single guest is needed on a host, we have a lot of spare host CPU time we can throw at the problem. Modern CPUs implement a feature called "MWAIT" which allows guests to wake up sleeping remote CPUs without an IPI - thus without an exit - at the expense of never going out of guest context. The decision whether this is something sensible to use should be up to the VM admin, so to user space. We can however allow MWAIT execution on systems that support it properly hardware wise. This patch adds a CAP to user space and a KVM cpuid leaf to indicate availability of native MWAIT execution. With that enabled, the worst a guest can do is waste as many cycles as a "jmp ." would do, so it's not a privilege problem. We consciously do *not* expose the feature in our CPUID bitmap, as most people will want to benefit from sleeping vCPUs to allow for over commit. Reported-by: "Gabriel L. Somlo" <gsomlo@gmail.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> [agraf: fix amd, change commit message] Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2017-04-21 12:50:28 +02:00
..
ABI	RTC for 4.11	2017-02-27 19:59:21 -08:00
DocBook	A few fixes for the docs tree, including one for a 4.11 build regression.	2017-03-04 11:32:18 -08:00
EDID	…
PCI	A few fixes for the docs tree, including one for a 4.11 build regression.	2017-03-04 11:32:18 -08:00
RCU	Merge branches 'doc.2017.01.15b', 'dyntick.2017.01.23a', 'fixes.2017.01.23a', 'srcu.2017.01.25a' and 'torture.2017.01.15b' into HEAD	2017-01-25 12:56:05 -08:00
accounting	tools: move accounting tool from Documentation	2016-09-23 13:07:15 -06:00
acpi	scripts/spelling.txt: add "followings" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
admin-guide	Power management updates for v4.11-rc2	2017-03-09 16:30:37 -08:00
aoe	…
arm	arm: sunxi: add support for V3s SoC	2017-01-20 21:31:34 +01:00
arm64	irqchip/gicv3-its: Add workaround for QDF2400 ITS erratum 0065	2017-03-07 14:34:27 +00:00
auxdisplay	samples: move auxdisplay example code from Documentation	2016-09-23 11:52:32 -06:00
backlight	…
blackfin	samples: move blackfin gptimers-example from Documentation	2016-10-10 07:12:02 -06:00
block	A slightly quieter cycle for documentation this time around.	2017-02-22 18:51:29 -08:00
blockdev	scripts/spelling.txt: add "followings" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
bus-devices	…
cdrom	cdrom: Make device operations read-only	2017-02-14 08:29:56 -07:00
cgroup-v1	Merge branch 'for-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2017-02-27 21:41:08 -08:00
cma	…
connector	…
console	…
core-api	Documentation: Update CPU hotplug and move it to core-api	2017-01-13 10:32:32 -07:00
cpu-freq	A slightly quieter cycle for documentation this time around.	2017-02-22 18:51:29 -08:00
cpuidle	…
cris	…
crypto	crypto: doc - fix typo	2017-02-15 13:23:49 +08:00
dev-tools	scripts/spelling.txt: add "disble(d)" pattern and fix typo instances	2017-03-09 17:01:09 -08:00
device-mapper	scripts/spelling.txt: add "explictely" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
devicetree	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-03-14 21:31:23 -07:00
dmaengine	dmaengine: Documentation: Fix typo in pxa_dma.txt	2016-11-14 08:14:24 +05:30
doc-guide	docs-rst: parse-headers.pl: cleanup the documentation	2016-11-30 17:08:09 -07:00
driver-api	Less anger inducing pull request for 4.11	2017-02-23 18:58:18 -08:00
driver-model	irqdesc: Add a resource managed version of irq_alloc_descs()	2017-02-10 14:39:20 +01:00
early-userspace	…
extcon	extcon: int3496: Add Intel INT3496 ACPI device extcon driver	2017-01-09 10:04:11 +09:00
fault-injection	…
fb	Documentation: fb: fix spelling mistakes	2016-05-10 12:05:27 +03:00
features	2nd round of ARC udpates for 4.10rc1	2016-12-23 10:22:47 -08:00
filesystems	statx: Add a system call to make enhanced file info available	2017-03-02 20:51:15 -05:00
firmware_class	firmware: revamp firmware documentation	2017-01-11 09:42:59 +01:00
fmc	…
fpga	fpga: Add scatterlist based programming	2017-02-10 15:20:44 +01:00
frv	docs: fix locations of several documents that got moved	2016-10-24 08:12:35 -02:00
gpio	gpio: random documentation update	2017-01-31 15:43:05 +01:00
gpu	Less anger inducing pull request for 4.11	2017-02-23 18:58:18 -08:00
hid	Documentation: HID: Intel ISH HID document	2016-08-17 11:13:07 +02:00
hwmon	A slightly quieter cycle for documentation this time around.	2017-02-22 18:51:29 -08:00
i2c	i2c: i801: Add support for Intel Gemini Lake	2017-02-09 17:39:16 +01:00
ia64	selftests: move ia64 tests from Documentation/ia64	2016-09-20 09:58:12 -06:00
ide	…
iio	iio: Documentation: Correct the path used to create triggers.	2016-10-01 00:49:58 -06:00
infiniband	IB/hfi1: Document new sysfs entries for hfi1 driver	2016-10-02 08:42:19 -04:00
input	Documentation: input: fix path to input code definitions	2017-02-12 15:19:00 -07:00
ioctl	rpmsg updates for v4.11	2017-02-23 09:41:03 -08:00
isdn	docs: fix locations of several documents that got moved	2016-10-24 08:12:35 -02:00
kbuild	Kconfig: Introduce the "imply" keyword	2016-11-16 09:26:33 +01:00
kdump	Documentation: kdump: Add description of enable multi-cpus support	2016-09-20 18:02:54 -06:00
laptops	platform/x86: thinkpad_acpi: Add support for X1 Yoga (2016) Tablet Mode	2016-12-13 09:29:06 -08:00
leds	leds: class: Add new optional brightness_hw_changed attribute	2017-01-29 19:59:42 +01:00
livepatch	A slightly quieter cycle for documentation this time around.	2017-02-22 18:51:29 -08:00
locking	locking/ww_mutex/Documentation: Update the design document	2017-01-14 11:14:55 +01:00
m68k	docs: fix locations of several documents that got moved	2016-10-24 08:12:35 -02:00
md	MD: add doc for raid5-cache	2017-02-13 09:17:54 -08:00
media	A few fixes for the docs tree, including one for a 4.11 build regression.	2017-03-04 11:32:18 -08:00
memory-devices	…
metag	…
mic	samples: move mic/mpssd example code from Documentation	2016-09-20 12:38:48 -06:00
mips	…
misc-devices	samples: move misc-devices/mei example code from Documentation	2016-09-23 11:51:43 -06:00
mmc	mmc: core: Extend sysfs with DSR register	2016-07-25 10:34:51 +02:00
mn10300	…
mtd	spi-nor: Add support for Intel SPI serial flash controller	2017-01-03 17:33:36 +00:00
namespaces	…
netlabel	…
networking	Make IP 'forwarding' doc more precise	2017-03-12 23:28:43 -07:00
nfc	…
nios2	…
nvdimm	libnvdimm, btt: update the usage section in Documentation	2016-06-17 16:23:23 -07:00
nvmem	…
parisc	…
pcmcia	tools: move pcmcia crc32hash tool from Documentation	2016-09-23 13:07:27 -06:00
perf	perf: add qcom l2 cache perf events driver	2017-02-08 19:32:24 +00:00
phy	…
platform	…
power	More power management updates for v4.11-rc1	2017-03-02 17:33:52 -08:00
powerpc	powerpc updates for 4.9	2016-10-07 20:19:31 -07:00
pps	Doc: clarify source of jitter in USB1.1, and USB2.0	2017-01-04 14:40:52 -07:00
prctl	selftests: move prctl tests from Documentation/prctl	2016-09-20 09:09:09 -06:00
process	Doc: Correct typo, "Introdution" => "Introduction"	2016-12-01 10:44:08 -07:00
pti	…
ptp	selftests: move ptp tests from Documentation/ptp	2016-09-20 09:54:38 -06:00
rapidio	rapidio/documentation/mport_cdev: add missing parameter description	2016-09-01 17:52:02 -07:00
s390	Documentation: Update path to sysrq.txt	2017-03-03 15:48:38 -07:00
scheduler	sched/Documentation/sched-rt-group: Fix incorrect example	2017-01-22 10:34:17 +01:00
scsi	scripts/spelling.txt: add "varible" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
security	KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload()	2017-03-02 10:09:00 +11:00
serial	Documentation: rs485: Do not define manually the ioctl	2016-08-18 11:08:33 -06:00
sh	…
sound	scripts/spelling.txt: add "followings" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
sparc	Documentation/sparc: Steps for sending break on sunhv console	2017-02-23 08:27:25 -08:00
sphinx	docs: sphinx-extensions: make rstFlatTable work with docutils 0.13	2016-12-18 13:30:29 -07:00
sphinx-static	This is the documentation update pull for the 4.9 merge window.	2016-10-04 13:54:07 -07:00
spi	spi: spi-ep93xx: simplify GPIO chip selects	2017-02-16 20:10:26 +00:00
sysctl	A few fixes for the docs tree, including one for a 4.11 build regression.	2017-03-04 11:32:18 -08:00
target	target: make close_session optional	2016-05-10 01:19:26 -07:00
thermal	Documentation: fix spelling mistakes of "Celcius" -- > "Celsius"	2017-01-04 14:36:17 -07:00
timers	time: Remove CONFIG_TIMER_STATS	2017-02-10 11:15:08 +01:00
trace	perf/core: Rename CONFIG_[UK]PROBE_EVENT to CONFIG_[UK]PROBE_EVENTS	2017-03-01 10:26:39 +01:00
translations	doc/ko_KR/memory-barriers: Update control-dependencies section	2017-03-03 15:54:55 -07:00
usb	A slightly quieter cycle for documentation this time around.	2017-02-22 18:51:29 -08:00
virtual	kvm: better MWAIT emulation for guests	2017-04-21 12:50:28 +02:00
vm	userfaultfd: non-cooperative: rollback userfaultfd_exit	2017-03-09 17:01:09 -08:00
w1	…
watchdog	watchdog: Introduce watchdog_stop_on_unregister helper	2017-02-24 14:00:23 -08:00
wimax	…
x86	Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-02-28 11:46:00 -08:00
xtensa	xtensa: cleanup MMU setup and kernel layout macros	2016-07-24 06:33:58 +03:00
.gitignore	Add .pyc files to .gitignore	2016-06-30 13:07:33 -06:00
00-INDEX	Documentation: move MD related doc into a separate dir	2017-02-13 09:17:53 -08:00
Changes	docs: add back 'Documentation/Changes' file (as symlink)	2016-12-14 16:30:12 -08:00
CodingStyle	doc: re-add CodingStyle and SubmittingPatches	2016-10-24 08:12:35 -02:00
DMA-API-HOWTO.txt	Documentation: DMA-API-HOWTO: Fix a typo	2016-09-20 17:58:46 -06:00
DMA-API.txt	dma-mapping: add dma_{map,unmap}_resource	2016-09-26 22:16:41 +05:30
DMA-ISA-LPC.txt	Documentation: DMA-ISA-LPC.txt	2017-02-12 15:20:07 -07:00
DMA-attributes.txt	common: DMA-mapping: add DMA_ATTR_PRIVILEGED attribute	2017-01-19 15:56:19 +00:00
IPMI.txt	Documentation: Fix a typo in IPMI.txt.	2017-01-05 15:01:54 -06:00
IRQ-affinity.txt	…
IRQ-domain.txt	…
IRQ.txt	…
Intel-IOMMU.txt	…
Makefile	samples: move blackfin gptimers-example from Documentation	2016-10-10 07:12:02 -06:00
Makefile.sphinx	Add a target to check broken external links in the Documentation	2017-02-15 15:22:47 -07:00
SAK.txt	…
SM501.txt	…
SubmittingPatches	doc: re-add CodingStyle and SubmittingPatches	2016-10-24 08:12:35 -02:00
bcache.txt	bcache: documentation formatting, edited for clarity, stripe alignment notes	2016-06-23 07:58:38 -06:00
bt8xxgpio.txt	…
btmrvl.txt	…
bus-virt-phys-mapping.txt	…
cachetlb.txt	…
cgroup-v2.txt	cgroup: Fix indenting in PID controller documentation	2017-03-06 14:46:27 -05:00
circular-buffers.txt	Documentation: circular-buffers: use READ_ONCE()	2016-11-16 16:17:45 -07:00
clk.txt	Documentation: clk: update file names containing referenced structures	2016-08-14 12:12:36 -06:00
conf.py	Documentation/sphinx: fix primary_domain configuration	2017-03-03 16:12:30 -07:00
cpu-load.txt	…
cputopology.txt	topology/sysfs: provide drawer id and siblings attributes	2016-06-13 15:58:27 +02:00
crc32.txt	…
dcdbas.txt	…
debugging-modules.txt	…
debugging-via-ohci1394.txt	…
dell_rbu.txt	…
digsig.txt	…
docutils.conf	doc-rst: add docutils config file	2016-08-14 11:52:40 -06:00
dontdiff	Documentation: dontdiff: Update with additional entries	2017-01-26 15:08:06 -07:00
efi-stub.txt	…
eisa.txt	…
flexible-arrays.txt	…
futex-requeue-pi.txt	…
gcc-plugins.txt	GCC plugin infrastructure	2016-06-07 22:57:10 +02:00
highuid.txt	…
hw_random.txt	…
hwspinlock.txt	…
index.rst	docs/zh_CN: Add coding-style into docs build system	2017-01-26 15:30:34 -07:00
intel_txt.txt	…
io-mapping.txt	…
io_ordering.txt	…
iostats.txt	…
irqflags-tracing.txt	…
isa.txt	…
isapnp.txt	…
kernel-doc-nano-HOWTO.txt	docs-rst: doc-guide: split the kernel-documentation.rst contents	2016-11-19 10:22:04 -07:00
kernel-per-CPU-kthreads.txt	docs: fix locations of several documents that got moved	2016-10-24 08:12:35 -02:00
kobject.txt	…
kprobes.txt	Documentation: kprobes: Document jprobes stack copying limitations	2016-08-15 10:19:11 -06:00
kref.txt	…
kselftest.txt	scripts/spelling.txt: add "an user" pattern and fix typo instances	2017-02-27 18:43:46 -08:00
ldm.txt	…
lockup-watchdogs.txt	docs: fix locations of several documents that got moved	2016-10-24 08:12:35 -02:00
logo.gif	…
logo.txt	…
lzo.txt	…
mailbox.txt	…
memory-barriers.txt	doc: Update control-dependencies section of memory-barriers.txt	2017-01-14 21:29:15 -08:00
memory-hotplug.txt	scripts/spelling.txt: add "followings" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
men-chameleon-bus.txt	…
nommu-mmap.txt	…
ntb.txt	…
numastat.txt	…
padata.txt	…
parport-lowlevel.txt	…
percpu-rw-semaphore.txt	…
phy.txt	…
pi-futex.txt	…
pinctrl.txt	pinctrl: core: Fix regression caused by delayed work for hogs	2017-01-13 16:25:17 +01:00
pnp.txt	…
preempt-locking.txt	…
printk-formats.txt	…
pwm.txt	pwm: Update documentation	2016-05-17 14:48:04 +02:00
rbtree.txt	…
remoteproc.txt	remoteproc: Split driver and consumer dereferencing	2016-10-02 22:50:21 -07:00
rfkill.txt	docs: fix locations of several documents that got moved	2016-10-24 08:12:35 -02:00
robust-futex-ABI.txt	…
robust-futexes.txt	…
rpmsg.txt	rpmsg: use module_rpmsg_driver in existing drivers and examples	2016-05-06 11:09:01 -07:00
rtc.txt	…
sgi-ioc4.txt	…
siphash.txt	siphash: implement HalfSipHash1-3 for hash tables	2017-01-09 13:58:57 -05:00
smsc_ece1099.txt	…
static-keys.txt	jump_label: Reduce the size of struct static_key	2017-02-15 09:02:26 -05:00
svga.txt	…
sync_file.txt	dma-buf: Rename struct fence to dma_fence	2016-10-25 14:40:39 +02:00
this_cpu_ops.txt	…
unaligned-memory-access.txt	Documentation/unaligned-memory-access.txt: fix incorrect comparison operator	2016-12-27 13:08:42 -07:00
unshare.txt	…
vfio-mediated-device.txt	vfio-mdev: Make mdev_parent private	2016-12-30 08:13:41 -07:00
vfio.txt	…
video-output.txt	…
xillybus.txt	…
xz.txt	…
zorro.txt	…