kernel_optimize_test/arch/arm
Christoffer Dall 1a74847885 arm/arm64: KVM: Fix migration race in the arch timer
When a VCPU is no longer running, we currently check to see if it has a
timer scheduled in the future, and if it does, we schedule a host
hrtimer to notify is in case the timer expires while the VCPU is still
not running.  When the hrtimer fires, we mask the guest's timer and
inject the timer IRQ (still relying on the guest unmasking the time when
it receives the IRQ).

This is all good and fine, but when migration a VM (checkpoint/restore)
this introduces a race.  It is unlikely, but possible, for the following
sequence of events to happen:

 1. Userspace stops the VM
 2. Hrtimer for VCPU is scheduled
 3. Userspace checkpoints the VGIC state (no pending timer interrupts)
 4. The hrtimer fires, schedules work in a workqueue
 5. Workqueue function runs, masks the timer and injects timer interrupt
 6. Userspace checkpoints the timer state (timer masked)

At restore time, you end up with a masked timer without any timer
interrupts and your guest halts never receiving timer interrupts.

Fix this by only kicking the VCPU in the workqueue function, and sample
the expired state of the timer when entering the guest again and inject
the interrupt and mask the timer only then.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-03-14 13:48:00 +01:00
..
boot ARM: SoC fixes for 3.20-rc1 2015-02-21 19:21:54 -08:00
common
configs ARM: SoC defconfig changes 2015-02-17 09:44:50 -08:00
crypto
firmware
include arm/arm64: KVM: Implement Stage-2 page aging 2015-03-12 22:34:43 +01:00
kernel arm/arm64: KVM: Kill CONFIG_KVM_ARM_{VGIC,TIMER} 2015-03-12 15:15:27 +01:00
kvm arm/arm64: KVM: Fix migration race in the arch timer 2015-03-14 13:48:00 +01:00
lib
mach-asm9260
mach-at91 ARM: make of_device_ids const 2015-02-19 09:44:25 +01:00
mach-axxia ARM: make arrays containing machine compatible strings const 2015-02-19 09:44:17 +01:00
mach-bcm ARM: make arrays containing machine compatible strings const 2015-02-19 09:44:17 +01:00
mach-berlin
mach-clps711x
mach-cns3xxx Merge branch 'pci/config' into next 2015-02-02 14:49:29 -06:00
mach-davinci ARM: make of_device_ids const 2015-02-19 09:44:25 +01:00
mach-digicolor ARM: digicolor: select syscon and timer 2015-01-29 13:52:06 -08:00
mach-dove
mach-ebsa110
mach-efm32
mach-ep93xx
mach-exynos ARM: make of_device_ids const 2015-02-19 09:44:25 +01:00
mach-footbridge
mach-gemini
mach-highbank ARM: make arrays containing machine compatible strings const 2015-02-19 09:44:17 +01:00
mach-hisi ARM: make arrays containing machine compatible strings const 2015-02-19 09:44:17 +01:00
mach-imx ARM: make of_device_ids const 2015-02-19 09:44:25 +01:00
mach-integrator ARM: integrator: Convert PCI to use generic config accessors 2015-01-29 08:34:42 -06:00
mach-iop13xx
mach-iop32x
mach-iop33x
mach-ixp4xx ARM: ixp4xx: fix {in,out}s{bwl} data types 2015-02-18 12:20:27 +01:00
mach-keystone ARM: make of_device_ids const 2015-02-19 09:44:25 +01:00
mach-ks8695 Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm 2015-02-12 08:51:56 -08:00
mach-lpc32xx
mach-mediatek
mach-meson
mach-mmp ARM: make of_device_ids const 2015-02-19 09:44:25 +01:00
mach-moxart
mach-msm
mach-mv78xx0
mach-mvebu ARM: make of_device_ids const 2015-02-19 09:44:25 +01:00
mach-mxs
mach-netx
mach-nomadik
mach-nspire ARM: make arrays containing machine compatible strings const 2015-02-19 09:44:17 +01:00
mach-omap1 ARM: SoC cleanups 2015-02-17 09:17:33 -08:00
mach-omap2 ARM: SoC fixes for 3.20-rc1 2015-02-21 19:21:54 -08:00
mach-orion5x
mach-picoxcell
mach-prima2 ARM: make of_device_ids const 2015-02-19 09:44:25 +01:00
mach-pxa ARM: SoC cleanups 2015-02-17 09:17:33 -08:00
mach-qcom ARM: SoC platform changes 2015-02-17 09:27:54 -08:00
mach-realview arm: realview: specify PMU types 2015-02-06 00:12:55 -08:00
mach-rockchip ARM: rockchip: force built-in regulator support for PM 2015-02-18 12:20:30 +01:00
mach-rpc
mach-s3c24xx
mach-s3c64xx
mach-s5pv210 ARM: make arrays containing machine compatible strings const 2015-02-19 09:44:17 +01:00
mach-sa1100 Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm 2015-02-12 08:51:56 -08:00
mach-shmobile ARM: make arrays containing machine compatible strings const 2015-02-19 09:44:17 +01:00
mach-socfpga
mach-spear
mach-sti ARM: sti: always enable RESET_CONTROLLER 2015-02-18 12:20:29 +01:00
mach-sunxi
mach-tegra The clock framework changes for 3.20 contain the usual driver additions, 2015-02-21 12:30:30 -08:00
mach-u300
mach-ux500 ARM: make of_device_ids const 2015-02-19 09:44:25 +01:00
mach-versatile ARM: make arrays containing machine compatible strings const 2015-02-19 09:44:17 +01:00
mach-vexpress ARM: vexpress: use ARM_CPU_SUSPEND if needed 2015-02-18 12:19:09 +01:00
mach-vt8500
mach-w90x900
mach-zynq ARM: zynq: Simplify SLCR initialization 2015-01-29 15:38:17 +01:00
mm Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm 2015-02-22 09:57:16 -08:00
net
nwfpe
oprofile
plat-iop arm: iop: specify PMUs are for XScale CPUs 2015-02-06 00:12:59 -08:00
plat-omap
plat-orion
plat-pxa
plat-samsung ARM: SoC platform changes 2015-02-17 09:27:54 -08:00
plat-versatile
probes ARM: kprobes: Fix compilation error caused by superfluous '*' 2015-02-10 15:05:30 +08:00
tools
vfp
xen xen/grant-table: pre-populate kernel unmap ops for xen_gnttab_unmap_refs() 2015-01-28 14:03:10 +00:00
Kconfig ARM: SoC platform changes 2015-02-17 09:27:54 -08:00
Kconfig-nommu
Kconfig.debug ARM: SoC platform changes 2015-02-17 09:27:54 -08:00
Makefile