David Matlack ee3d1570b5 kvm: fix potentially corrupt mmio cache ... vcpu exits and memslot mutations can run concurrently as long as the vcpu does not aquire the slots mutex. Thus it is theoretically possible for memslots to change underneath a vcpu that is handling an exit. If we increment the memslot generation number again after synchronize_srcu_expedited(), vcpus can safely cache memslot generation without maintaining a single rcu_dereference through an entire vm exit. And much of the x86/kvm code does not maintain a single rcu_dereference of the current memslots during each exit. We can prevent the following case: vcpu (CPU 0) | thread (CPU 1) --------------------------------------------+-------------------------- 1 vm exit | 2 srcu_read_unlock(&kvm->srcu) | 3 decide to cache something based on | old memslots | 4 | change memslots | (increments generation) 5 | synchronize_srcu(&kvm->srcu); 6 retrieve generation # from new memslots | 7 tag cache with new memslot generation | 8 srcu_read_unlock(&kvm->srcu) | ... | <action based on cache occurs even | though the caching decision was based | on the old memslots> | ... | <action *continues* to occur until next | memslot generation change, which may | be never> | | By incrementing the generation after synchronizing with kvm->srcu readers, we ensure that the generation retrieved in (6) will become invalid soon after (8). Keeping the existing increment is not strictly necessary, but we do keep it and just move it for consistency from update_memslots to install_new_memslots. It invalidates old cached MMIOs immediately, instead of having to wait for the end of synchronize_srcu_expedited, which makes the code more clearly correct in case CPU 1 is preempted right after synchronize_srcu() returns. To avoid halving the generation space in SPTEs, always presume that the low bit of the generation is zero when reconstructing a generation number out of an SPTE. This effectively disables MMIO caching in SPTEs during the call to synchronize_srcu_expedited. Using the low bit this way is somewhat like a seqcount---where the protected thing is a cache, and instead of retrying we can simply punt if we observe the low bit to be 1. Cc: stable@vger.kernel.org Signed-off-by: David Matlack <dmatlack@google.com> Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Reviewed-by: David Matlack <dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2014-09-03 10:03:41 +02:00
..
ABI	xfs: update for 3.17-rc1	2014-08-13 17:49:53 -06:00
DocBook	drm/doc: Refer to proper source file	2014-08-15 09:50:41 +10:00
EDID	drm: Add 800x600 (SVGA) screen resolution to the built-in EDIDs	2014-05-26 12:53:40 +10:00
PCI	doc: replace "practise" with "practice" in Documentation	2014-06-19 15:28:56 +02:00
RCU	list: fix order of arguments for hlist_add_after(_rcu)	2014-08-06 18:01:24 -07:00
accounting	Documentation/accounting/getdelays.c: add missing null-terminate after strncpy call	2014-06-23 16:47:44 -07:00
acpi	ACPI / documentation: Remove reference to acpi_platform_device_ids from enumeration.txt	2014-07-12 00:07:05 +02:00
aoe	…
arm	ARM: SoC driver changes for 3.17	2014-08-08 11:34:32 -07:00
arm64	KVM/ARM New features for 3.17 include:	2014-08-05 09:47:45 +02:00
auxdisplay	…
backlight	…
blackfin	Documentation/: update 00-INDEX files	2014-02-10 16:01:40 -08:00
block	Documentation/: update 00-INDEX files	2014-02-10 16:01:40 -08:00
blockdev	zram: propagate error to user	2014-04-07 16:36:02 -07:00
bus-devices	…
cdrom	…
cgroups	mm: memcontrol: rewrite uncharge API	2014-08-08 15:57:17 -07:00
connector	w1: optional bundling of netlink kernel replies	2014-05-27 13:56:21 -07:00
console	…
cpu-freq	intel_pstate: Update documentation of {max,min}_perf_pct sysfs files	2014-07-07 01:22:19 +02:00
cpuidle	…
cris	…
crypto	…
development-process	…
device-mapper	dm switch: efficiently support repetitive patterns	2014-08-01 12:30:37 -04:00
devicetree	The branch contains the following device tree changes the v3.17 merge	2014-08-14 09:53:39 -06:00
driver-model	Documentation: devres: Sort managed interfaces	2014-07-11 17:56:55 -07:00
dvb	[media] get_dvb_firmware: Add firmware extractor for si2165	2014-07-27 17:01:12 -03:00
early-userspace	…
extcon	extcon: fix switch class porting guide (Documentation)	2014-01-07 11:54:28 +09:00
fault-injection	…
fb	doc: spelling error changes	2014-05-05 15:32:05 +02:00
filesystems	File locking related bugfixes for v3.17 (pile #2)	2014-08-16 08:58:47 -06:00
firmware_class	doc: fix minor typos in firmware_class README	2014-07-17 18:43:40 -07:00
fmc	FMC: make eeprom attribute writable	2014-02-28 15:12:08 -08:00
frv	…
gpio	gpio: add flags argument to gpiod_get*() functions	2014-07-28 12:28:05 +02:00
hid	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial into next	2014-06-04 08:50:34 -07:00
hwmon	hwmon: Add pwm-fan driver	2014-08-04 07:01:38 -07:00
i2c	i2c: i801: Add device ID for Intel Wildcat Point PCH	2014-07-17 19:56:23 +02:00
i2o	…
ia64	…
ide	Documentation/: update 00-INDEX files	2014-02-10 16:01:40 -08:00
infiniband	IB/mad: add new ioctl to ABI to support new registration options	2014-08-10 20:36:00 -07:00
input	Merge branch 'next' into for-linus	2014-08-06 23:36:12 -07:00
ioctl	Documentation: add How to avoid botching up ioctls	2014-08-09 09:13:40 -07:00
isdn	…
ja_JP	Documentation: Update stable address in Chinese and Japanese translations	2014-04-16 14:13:27 -07:00
kbuild	Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild	2014-08-14 11:14:29 -06:00
kdump	…
ko_KR	Documentation: HOWTO: Updates on subsystem trees, patchwork, -next (vs. -mm) in ko_KR	2014-01-08 15:32:51 -08:00
laptops	Documentation: Add file about toshiba_haps module	2014-08-16 01:23:56 -07:00
leds	Documentation/: update 00-INDEX files	2014-02-10 16:01:40 -08:00
m68k	Documentation/: update 00-INDEX files	2014-02-10 16:01:40 -08:00
memory-devices	…
metag	…
mic	misc: mic: add support for loading/unloading dma driver	2014-07-11 18:31:12 -07:00
mips	…
misc-devices	Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging	2014-01-29 18:56:27 -08:00
mmc	…
mn10300	…
mtd	MTD updates for 3.16:	2014-06-11 08:35:34 -07:00
namespaces	…
netlabel	…
networking	i40e: adds FCoE to build and updates its documentation	2014-08-02 19:41:13 -07:00
nfc	…
parisc	…
pcmcia	…
phy	phy: Add new Exynos USB 2.0 PHY driver	2014-03-08 12:39:44 +05:30
platform	Documentation: Add list of laptop models supported by the Compal driver	2014-06-10 19:11:06 -04:00
power	ACPI and power management updates for 3.17-rc1	2014-08-06 20:34:19 -07:00
powerpc	KVM: PPC: Remove 440 support	2014-07-28 15:23:15 +02:00
pps	…
prctl	…
pti	…
ptp	ptp: In the testptp utility, use clock_adjtime from glibc when available	2014-06-16 21:32:31 -07:00
rapidio	rapidio/tsi721_dma: rework scatter-gather list handling	2014-08-08 15:57:24 -07:00
s390	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial into next	2014-06-04 08:50:34 -07:00
scheduler	asm/system.h: clean asm/system.h from docs	2014-04-07 16:36:11 -07:00
scsi	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2014-08-06 21:03:53 -07:00
security	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2014-08-06 21:03:53 -07:00
serial	tty/serial: Add GPIOLIB helpers for controlling modem lines	2014-05-28 12:49:14 -07:00
sh	…
sound	ALSA: virtuoso: add Xonar Essence STX II support	2014-08-04 15:20:48 +02:00
spi	Merge remote-tracking branches 'spi/topic/s3c64xx', 'spi/topic/sc18is602', 'spi/topic/sh-hspi', 'spi/topic/sh-msiof', 'spi/topic/sh-sci', 'spi/topic/sirf' and 'spi/topic/spidev' into spi-next	2014-03-30 00:51:34 +00:00
sysctl	panic: add TAINT_SOFTLOCKUP	2014-08-08 15:57:24 -07:00
target	…
thermal	drm/nouveau/doc: update the thermal documentation	2014-06-17 14:50:17 +10:00
timers	clocksource: document some basic timekeeping concepts	2014-07-23 15:07:13 -07:00
tpm	…
trace	mm: trace-vmscan-postprocess.pl: report the number of file/anon pages respectively	2014-08-06 18:01:20 -07:00
usb	usb: doc: hotplug.txt code typos	2014-07-09 16:05:42 -07:00
vDSO	x86/vdso/doc: Make vDSO examples more portable	2014-06-12 19:01:24 -07:00
video4linux	[media] update cx23885 and em28xx cardlists	2014-07-26 11:55:10 -03:00
virtual	kvm: fix potentially corrupt mmio cache	2014-09-03 10:03:41 +02:00
vm	mm: mark remap_file_pages() syscall as deprecated	2014-06-06 16:08:17 -07:00
w1	w1: new w1_ds2406 driver	2014-06-19 17:45:14 -07:00
watchdog	Documentation: fix two typos in watchdog-api.txt	2014-08-05 22:43:21 +02:00
wimax	…
x86	x86/mm: New tunable for single vs full TLB flush	2014-07-31 08:48:51 -07:00
xtensa	xtensa: remap io area defined in device tree	2014-01-15 00:25:14 +04:00
zh_CN	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2014-08-06 21:03:53 -07:00
.gitignore	…
00-INDEX	Merge branch 'x86-nuke-platforms-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-04-02 13:15:58 -07:00
BUG-HUNTING	…
Changes	Documentation/Changes: clean up mcelog paragraph	2014-07-12 11:30:36 -07:00
CodingStyle	Documentation: expand/clarify debug documentation	2014-06-04 16:54:17 -07:00
DMA-API-HOWTO.txt	DMA-API: Update dma_pool_create ()and dma_pool_alloc() descriptions	2014-05-26 17:28:28 -06:00
DMA-API.txt	DMA-API: Capitalize "CPU" consistently	2014-05-26 17:28:27 -06:00
DMA-ISA-LPC.txt	DMA-API: Clarify physical/bus address distinction	2014-05-20 16:54:21 -06:00
DMA-attributes.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
HOWTO	…
IPMI.txt	…
IRQ-affinity.txt	…
IRQ-domain.txt	genirq: Improve documentation to match current implementation	2014-05-27 10:16:44 +02:00
IRQ.txt	…
Intel-IOMMU.txt	…
Makefile	…
ManagementStyle	…
SAK.txt	…
SM501.txt	…
SecurityBugs	…
SubmitChecklist	…
SubmittingDrivers	doc: SubmittingPatches: remove dead link, kerneltrap.org no longer works	2014-06-19 15:15:27 +02:00
SubmittingPatches	Documentation: SubmittingPatches: overhaul changelog description	2014-08-09 09:13:40 -07:00
VGA-softcursor.txt	…
applying-patches.txt	…
assoc_array.txt	…
atomic_ops.txt	arch,doc: Convert smp_mb__*()	2014-04-18 14:20:48 +02:00
bad_memory.txt	…
basic_profiling.txt	…
bcache.txt	…
binfmt_misc.txt	…
braille-console.txt	…
bt8xxgpio.txt	…
btmrvl.txt	…
bus-virt-phys-mapping.txt	…
cachetlb.txt	…
circular-buffers.txt	…
clk.txt	clk: Improve clk_ops documentation	2014-05-12 17:08:33 -07:00
coccinelle.txt	…
cpu-hotplug.txt	Doc/cpu-hotplug: Specify race-free way to register CPU hotplug callbacks	2014-03-20 13:43:40 +01:00
cpu-load.txt	…
cputopology.txt	…
crc32.txt	…
dcdbas.txt	…
debugging-modules.txt	…
debugging-via-ohci1394.txt	firewire: revert to 4 GB RDMA, fix protocols using Memory Space	2014-05-29 15:50:30 +02:00
dell_rbu.txt	…
devices.txt	Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media	2014-04-04 09:50:07 -07:00
digsig.txt	…
dma-buf-sharing.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
dmaengine.txt	dmaengine: Clarify device parameter for dma_sync_*_for_*()	2014-07-25 14:21:23 +05:30
dmatest.txt	…
dontdiff	Documentation: LLVMLinux: Update Documentation/dontdiff	2014-04-09 13:44:34 -07:00
dynamic-debug-howto.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
edac.txt	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial into next	2014-06-04 08:50:34 -07:00
efi-stub.txt	doc: arm64: add description of EFI stub support	2014-04-30 19:57:05 +01:00
eisa.txt	…
email-clients.txt	Documentation: add section about git to email-clients.txt	2014-06-29 13:38:33 -07:00
flexible-arrays.txt	…
futex-requeue-pi.txt	doc: fix double words	2014-03-21 13:16:58 +01:00
gcov.txt	…
highuid.txt	…
hsi.txt	Documentation: HSI: Add some general description for the HSI subsystem	2014-05-04 09:49:46 +02:00
hw_random.txt	…
hwspinlock.txt	…
init.txt	…
initrd.txt	…
intel_txt.txt	…
io-mapping.txt	…
io_ordering.txt	…
iostats.txt	…
irqflags-tracing.txt	asm/system.h: clean asm/system.h from docs	2014-04-07 16:36:11 -07:00
isapnp.txt	…
java.txt	Documentation: update java sample wrapper for java 7	2014-05-25 12:39:00 -07:00
kernel-doc-nano-HOWTO.txt	…
kernel-docs.txt	…
kernel-parameters.txt	Merge branch 'x86-xsave-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-08-13 18:20:04 -06:00
kernel-per-CPU-kthreads.txt	Documentation/kernel-per-CPU-kthreads.txt: Workqueue affinity	2014-02-17 14:56:08 -08:00
kmemcheck.txt	doc: fix double words	2014-03-21 13:16:58 +01:00
kmemleak.txt	mm: introduce kmemleak_update_trace()	2014-06-06 16:08:17 -07:00
kobject.txt	…
kprobes.txt	kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist	2014-04-24 10:02:56 +02:00
kref.txt	…
ldm.txt	…
local_ops.txt	…
lockdep-design.txt	…
lockstat.txt	…
lockup-watchdogs.txt	…
logo.gif	…
logo.txt	…
magic-number.txt	Documentation/serial: Delete obsolete driver documentation	2014-04-16 14:20:34 -07:00
md.txt	…
media-framework.txt	…
memory-barriers.txt	documentation: Add acquire/release barriers to pairing rules	2014-07-08 08:32:51 -07:00
memory-hotplug.txt	mm, hotplug: probe interface is available on several platforms	2014-06-23 16:47:43 -07:00
module-signing.txt	Nothing major: the stricter permissions checking for sysfs broke	2014-04-06 09:38:07 -07:00
mono.txt	…
mutex-design.txt	locking/mutexes: Documentation update/rewrite	2014-06-05 13:29:37 +02:00
nommu-mmap.txt	…
numastat.txt	…
oops-tracing.txt	panic: add TAINT_SOFTLOCKUP	2014-08-08 15:57:24 -07:00
padata.txt	…
parport-lowlevel.txt	…
parport.txt	…
percpu-rw-semaphore.txt	…
phy.txt	phy: core: Let node ptr of PHY point to PHY and not of PHY provider	2014-07-22 12:46:11 +05:30
pi-futex.txt	…
pinctrl.txt	pinctrl: Fix some typos and grammar issues in the documentation	2014-01-15 13:59:50 +01:00
pnp.txt	…
preempt-locking.txt	…
printk-formats.txt	doc: printk-formats: do not mention casts for u64/s64	2014-05-05 15:32:42 +02:00
pwm.txt	pwm: modify PWM_LOOKUP to initialize all struct pwm_lookup members	2014-05-21 11:19:36 +02:00
ramoops.txt	…
rbtree.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
remoteproc.txt	…
rfkill.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
robust-futex-ABI.txt	…
robust-futexes.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
rpmsg.txt	…
rt-mutex-design.txt	…
rt-mutex.txt	…
rtc.txt	…
serial-console.txt	…
sgi-ioc4.txt	…
smsc_ece1099.txt	…
sparse.txt	…
spinlocks.txt	…
stable_api_nonsense.txt	…
stable_kernel_rules.txt	stable_kernel_rules: Add pointer to netdev-FAQ for network patches	2014-07-09 15:54:27 -07:00
static-keys.txt	…
svga.txt	…
sysfs-rules.txt	…
sysrq.txt	…
this_cpu_ops.txt	…
unaligned-memory-access.txt	…
unicode.txt	…
unshare.txt	…
vfio.txt	drivers/vfio: EEH support for VFIO PCI device	2014-08-05 15:28:48 +10:00
vgaarbiter.txt	…
video-output.txt	…
vme_api.txt	…
volatile-considered-harmful.txt	…
workqueue.txt	…
ww-mutex-design.txt	…
xz.txt	…
zorro.txt	…