Sean Christopherson 919f6cd8bb KVM: doc: Document the life cycle of a VM and its resources ... The series to add memcg accounting to KVM allocations[1] states: There are many KVM kernel memory allocations which are tied to the life of the VM process and should be charged to the VM process's cgroup. While it is correct to account KVM kernel allocations to the cgroup of the process that created the VM, it's technically incorrect to state that the KVM kernel memory allocations are tied to the life of the VM process. This is because the VM itself, i.e. struct kvm, is not tied to the life of the process which created it, rather it is tied to the life of its associated file descriptor. In other words, kvm_destroy_vm() is not invoked until fput() decrements its associated file's refcount to zero. A simple example is to fork() in Qemu and have the child sleep indefinitely; kvm_destroy_vm() isn't called until Qemu closes its file descriptor *and* the rogue child is killed. The allocations are guaranteed to be *accounted* to the process which created the VM, but only because KVM's per-{VM,vCPU} ioctls reject the ioctl() with -EIO if kvm->mm != current->mm. I.e. the child can keep the VM "alive" but can't do anything useful with its reference. Note that because 'struct kvm' also holds a reference to the mm_struct of its owner, the above behavior also applies to userspace allocations. Given that mucking with a VM's file descriptor can lead to subtle and undesirable behavior, e.g. memcg charges persisting after a VM is shut down, explicitly document a VM's lifecycle and its impact on the VM's resources. Alternatively, KVM could aggressively free resources when the creating process exits, e.g. via mmu_notifier->release(). However, mmu_notifier isn't guaranteed to be available, and freeing resources when the creator exits is likely to be error prone and fragile as KVM would need to ensure that it only freed resources that are truly out of reach. In practice, the existing behavior shouldn't be problematic as a properly configured system will prevent a child process from being moved out of the appropriate cgroup hierarchy, i.e. prevent hiding the process from the OOM killer, and will prevent an unprivileged user from being able to to hold a reference to struct kvm via another method, e.g. debugfs. [1]https://patchwork.kernel.org/patch/10806707/ Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2019-03-28 17:29:51 +01:00
..
ABI	device-dax for 5.1	2019-03-16 13:05:32 -07:00
accelerators	ocxl: Document new OCXL IOCTLs	2018-06-03 20:40:33 +10:00
accounting	psi: cgroup support	2018-10-26 16:26:32 -07:00
acpi	ACPI: Documentation: Fix path for acpidbg tool	2019-03-07 11:28:33 +01:00
admin-guide	for-5.1/block-post-20190315	2019-03-16 12:36:39 -07:00
aoe
arm	ARM: 8833/1: Ensure that NEON code always compiles with Clang	2019-02-12 15:20:09 +00:00
arm64	arm64 updates for 5.1:	2019-03-10 10:17:23 -07:00
auxdisplay	Doc: misc-devices: move lcd-panel-cgram.txt to auxdisplay/	2018-04-12 16:08:02 +02:00
backlight
block	block: document usage of bio iterator helpers	2019-02-15 08:40:12 -07:00
blockdev	zram: idle writeback fixes and cleanup	2019-01-08 17:15:10 -08:00
bpf	docs/bpf: minor casing/punctuation fixes	2019-03-02 00:40:04 +01:00
bus-devices
cdrom	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00
cgroup-v1	A fairly routine cycle for docs - lots of typo fixes, some new documents,	2019-03-09 09:56:17 -08:00
cma
connector
console	Documentation: corrections to console/console.txt	2018-08-10 16:09:40 -06:00
core-api	Merge branch 'akpm' (patches from Andrew)	2019-03-12 10:39:53 -07:00
cpu-freq	Documentation: cpu-freq: Frequencies aren't always sorted	2018-11-07 13:29:04 +01:00
crypto	crypto: skcipher - remove remnants of internal IV generators	2018-12-23 11:52:45 +08:00
dev-tools	Documentation/dev-tools: Use gcc version number instead svn revision number	2019-01-14 17:25:41 -07:00
device-mapper	dm cache: add support for discard passdown to the origin device	2019-03-05 14:53:52 -05:00
devicetree	irqchip updates for 5.1, take #2	2019-03-21 12:30:54 +01:00
doc-guide	docs: kernel-doc: typo "if ... if" -> "if ... is"	2019-02-17 15:38:47 -07:00
driver-api	dmaengine updates for v5.1-rc1	2019-03-14 09:11:54 -07:00
driver-model	Merge branches 'clk-optional', 'clk-devm-clkdev-register', 'clk-allwinner', 'clk-meson' and 'clk-renesas' into clk-next	2019-03-08 10:27:21 -08:00
early-userspace	Correct gen_init_cpio tool's documentation	2018-11-25 12:25:53 -07:00
EDID	Docs/EDID: Calculate CRC while building the code	2018-11-06 07:36:22 -07:00
extcon
fault-injection	doc: fault-injection: fix macro name in example	2019-01-07 15:36:11 -07:00
fb	fbdev: fbmem: convert CONFIG_FB_LOGO_CENTER into a cmd line option	2019-01-16 17:42:35 +01:00
features	Documentation/features: Add csky kernel features	2019-01-07 22:22:16 +08:00
filesystems	various tracing and debugging improvements, crediting fixes, some cleanup, and important fallocate fix (fixes three xfstests) and lock fix	2019-03-15 18:52:12 -07:00
firmware_class
fmc	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00
fpga	docs: fpga: add a document for FPGA Device Feature List (DFL) Framework Overview	2018-07-15 13:55:44 +02:00
gpio	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00
gpu	Merge drm/drm-next into drm-misc-next	2019-02-11 10:35:35 +01:00
hid	HID: doc: fix wrong data structure reference for UHID_OUTPUT	2018-12-18 14:55:22 +01:00
hwmon	A fairly routine cycle for docs - lots of typo fixes, some new documents,	2019-03-09 09:56:17 -08:00
i2c	i2c: gpio: fault-injector: add 'inject_panic' injector	2019-02-23 10:34:08 +01:00
ia64
ide	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00
iio
infiniband	Documentation/infiniband: update from locked to pinned_vm	2019-02-07 12:56:23 -07:00
input	doc: Change LXR references to elixir.bootlin.com	2019-02-01 16:05:03 -07:00
interconnect	interconnect: Add generic on-chip interconnect API	2019-01-22 13:37:25 +01:00
ioctl	seccomp: add a return code to trap to userspace	2018-12-11 16:28:41 -08:00
isdn	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00
kbuild	kbuild: force all architectures except um to include mandatory-y	2019-03-17 12:56:32 +09:00
kdump	kdump: Document kernel data exported in the vmcoreinfo note	2019-01-15 11:05:28 +01:00
kernel-hacking	doc:it_IT: translation for kernel-hacking	2018-07-26 16:21:09 -06:00
laptops	Documentation: fix lg-laptop.rst warnings	2019-02-11 08:27:47 -07:00
leds	Documentation: Use "while" instead of "whilst"	2018-11-20 09:30:43 -07:00
lightnvm
livepatch	livepatch: Remove signal sysfs attribute	2019-01-16 22:09:33 +01:00
locking	Documentation/locking/lockdep: Drop last two chars of sample states	2019-03-04 12:55:18 -07:00
m68k	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00
maintainer	docs: Fix more broken references	2018-06-15 18:11:26 -03:00
md
media	media: Documentation: fix several typos	2019-03-01 09:54:06 -05:00
memory-devices
mic
mips	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00
misc-devices	Documentation: add ibmvmc to toctree(index) and fix warnings	2019-01-14 08:37:17 -07:00
mmc	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00
mtd	Documentation: mtd: remove stale pxa3xx NAND controller documentation	2018-09-04 23:37:38 +02:00
namespaces
netlabel	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00
networking	A fairly routine cycle for docs - lots of typo fixes, some new documents,	2019-03-09 09:56:17 -08:00
nfc
nios2
nvdimm	libnvdimm/security: Add documentation for nvdimm security support	2018-12-21 12:44:41 -08:00
nvmem	Documentation: nvmem: document cell tables and lookup entries	2018-09-28 15:14:54 +02:00
openrisc
parisc	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00
PCI	pci-v4.20-changes	2018-10-25 06:50:48 -07:00
pcmcia	pcmcia: remove long deprecated pcmcia_request_exclusive_irq() function	2018-08-18 12:30:42 -07:00
perf	Documentation: perf: Add documentation for ThunderX2 PMU uncore driver	2018-12-06 12:29:47 +00:00
phy
platform
power	PM/EM: Document the Energy Model framework	2019-01-27 12:29:37 +01:00
powerpc	powerpc/fadump: Reservationless firmware assisted dump	2018-12-21 11:32:49 +11:00
pps
process	A fairly routine cycle for docs - lots of typo fixes, some new documents,	2019-03-09 09:56:17 -08:00
pti
ptp
rapidio
RCU	A fairly routine cycle for docs - lots of typo fixes, some new documents,	2019-03-09 09:56:17 -08:00
riscv	perf: riscv: Add Document for Future Porting Guide	2018-06-04 14:02:11 -07:00
s390	Documentation: Use "while" instead of "whilst"	2018-11-20 09:30:43 -07:00
scheduler	sched/doc: Document Energy Aware Scheduling	2019-01-27 12:29:37 +01:00
scsi	scsi: ufs-bsg: Allow reading descriptors	2019-02-27 09:00:02 -05:00
security	doc: security: Add kern-doc for lsm_hooks.h	2019-02-22 08:54:09 -07:00
serial	Documentation: Use "while" instead of "whilst"	2018-11-20 09:30:43 -07:00
sh	sh: remove board_time_init() callback	2018-12-18 16:13:04 +01:00
sound	ASoC: More changes for v5.1	2019-02-28 13:30:55 +01:00
sparc
sphinx	Documentation/sphinx: allow "functions" with no parameters	2018-06-30 07:52:42 -06:00
sphinx-static	docs: improve readability for people with poorer eyesight	2018-10-07 09:16:50 -06:00
spi	pxa2xx: replace spi_master with spi_controller	2019-01-23 10:59:56 +00:00
sysctl	A fairly routine cycle for docs - lots of typo fixes, some new documents,	2019-03-09 09:56:17 -08:00
target	scsi: target/core: Remove the write_pending_status() callback function	2019-02-04 21:23:59 -05:00
thermal	Documentation: Use "while" instead of "whilst"	2018-11-20 09:30:43 -07:00
timers	Docs: Correct /proc/stat path	2019-02-22 08:50:17 -07:00
trace	doc: trace: Fix documentation for uprobe_profile	2019-02-21 10:28:55 -05:00
translations	A fairly routine cycle for docs - lots of typo fixes, some new documents,	2019-03-09 09:56:17 -08:00
usb	usb: core: add option of only authorizing internal devices	2019-02-22 09:27:55 +01:00
userspace-api	x86/speculation: Add PR_SPEC_DISABLE_NOEXEC	2019-01-29 22:11:49 +01:00
virtual	KVM: doc: Document the life cycle of a VM and its resources	2019-03-28 17:29:51 +01:00
vm	docs: Use underscore not hyphen in label	2019-02-01 16:04:01 -07:00
w1	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00
watchdog	Documentation/watchdog: Add documentation mlx-wdt driver	2019-03-02 15:28:20 +01:00
wimax
x86	x86/resctrl: Avoid confusion over the new X86_RESCTRL config	2019-02-02 10:34:52 +01:00
xilinx	Documentation: xilinx: Add documentation for eemi APIs	2018-10-09 13:26:05 +02:00
xtensa	xtensa: document boot parameter passing	2019-02-03 18:06:19 -08:00
.gitignore
atomic_bitops.txt
atomic_t.txt
bt8xxgpio.txt
btmrvl.txt
bus-virt-phys-mapping.txt
Changes
clearing-warn-once.txt
CodingStyle
conf.py	This is a fairly typical cycle for documentation. There's some welcome	2018-10-24 18:01:11 +01:00
cpu-load.txt
cputopology.txt
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt	Documentation: remove stale firmware API reference	2018-05-14 16:44:41 +02:00
digsig.txt
DMA-API-HOWTO.txt	Documentation/DMA-API-HOWTO: update dma_mask sections	2019-02-20 07:29:47 -07:00
DMA-API.txt	virtio: fixes, cleanups	2019-03-10 12:47:57 -07:00
DMA-attributes.txt
DMA-ISA-LPC.txt	Documentation/DMA-ISA-LPC: fix an incorrect reference	2019-02-11 08:23:07 -07:00
docutils.conf
dontdiff	kernel/configs: use .incbin directive to embed config_data.gz	2019-03-07 18:32:02 -08:00
efi-stub.txt	efi_stub: update documentation on dtb= parameter	2018-09-09 14:46:44 -06:00
eisa.txt
futex-requeue-pi.txt
gcc-plugins.txt
highuid.txt
hw_random.txt
hwspinlock.txt
index.rst	Documentation: add ibmvmc to toctree(index) and fix warnings	2019-01-14 08:37:17 -07:00
intel_txt.txt
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt	block: Track DISCARD statistics and output them in stat and diskstat	2018-07-18 08:44:22 -06:00
IPMI.txt
IRQ-affinity.txt
IRQ-domain.txt
IRQ.txt
irqflags-tracing.txt
isa.txt
isapnp.txt
kernel-per-CPU-kthreads.txt	doc: Update removal of RCU-bh/sched update machinery	2018-08-30 10:59:48 -07:00
kobject.txt	kref/kobject: Improve documentation	2018-12-06 13:57:03 +01:00
kprobes.txt	kprobes/Documentation: Fix various typos	2018-06-22 11:10:55 +02:00
kref.txt
ldm.txt
lockup-watchdogs.txt
logo.gif
logo.txt
lsm.txt
lzo.txt	lib/lzo: separate lzo-rle from lzo	2019-03-07 18:32:03 -08:00
mailbox.txt
Makefile	kbuild: Add support for DT binding schema checks	2018-12-13 09:41:32 -06:00
memory-barriers.txt	Documentation: Use "while" instead of "whilst"	2018-11-20 09:30:43 -07:00
men-chameleon-bus.txt
nommu-mmap.txt	Documentation: nommu-map: Fix duplicate word typo	2018-06-26 09:01:27 -06:00
ntb.txt
numastat.txt
padata.txt
parport-lowlevel.txt
percpu-rw-semaphore.txt
phy.txt
pi-futex.txt
pnp.txt
preempt-locking.txt	Documentation: preempt-locking: Use better example	2018-10-12 11:35:47 -06:00
pwm.txt
rbtree.txt
remoteproc.txt
rfkill.txt	rfkill: Fix several typos in documentation	2018-06-15 13:36:08 +02:00
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
rtc.txt
SAK.txt
sgi-ioc4.txt
siphash.txt
SM501.txt
smsc_ece1099.txt
speculation.txt
static-keys.txt	static_keys.txt: Fix trivial spelling mistake	2019-02-06 16:44:16 -07:00
SubmittingPatches
svga.txt
switchtec.txt	NTB: switchtec_ntb: Update switchtec documentation with prerequisites for NTB	2018-10-11 11:28:53 -05:00
sync_file.txt
tee.txt
this_cpu_ops.txt
unaligned-memory-access.txt
vfio-mediated-device.txt	vfio/mdev: Check globally for duplicate devices	2018-06-08 10:24:27 -06:00
vfio.txt	vfio: fix documentation	2018-05-08 09:16:41 -06:00
video-output.txt
xillybus.txt
xz.txt
zorro.txt