qemu-patch-raspberry4/include/hw
Daniel Henrique Barboza d1c2e3ce3d spapr_drc.c: add hotunplug timeout for CPUs
There is a reliable way to make a CPU hotunplug fail in the pseries
machine. Hotplug a CPU A, then offline all other CPUs inside the guest
but A. When trying to hotunplug A the guest kernel will refuse to do it,
because A is now the last online CPU of the guest. PAPR has no 'error
callback' in this situation to report back to the platform, so the guest
kernel will deny the unplug in silent and QEMU will never know what
happened. The unplug pending state of A will remain until the guest is
shutdown or rebooted.

Previous attempts of fixing it (see [1] and [2]) were aimed at trying to
mitigate the effects of the problem. In [1] we were trying to guess
which guest CPUs were online to forbid hotunplug of the last online CPU
in the QEMU layer, avoiding the scenario described above because QEMU is
now failing in behalf of the guest. This is not robust because the last
online CPU of the guest can change while we're in the middle of the
unplug process, and our initial assumptions are now invalid. In [2] we
were accepting that our unplug process is uncertain and the user should
be allowed to spam the IRQ hotunplug queue of the guest in case the CPU
hotunplug fails.

This patch presents another alternative, using the timeout
infrastructure introduced in the previous patch. CPU hotunplugs in the
pSeries machine will now timeout after 15 seconds. This is a long time
for a single CPU unplug to occur, regardless of guest load - although
the user is *strongly* encouraged to *not* hotunplug devices from a
guest under high load - and we can be sure that something went wrong if
it takes longer than that for the guest to release the CPU (the same
can't be said about memory hotunplug - more on that in the next patch).

Timing out the unplug operation will reset the unplug state of the CPU
and allow the user to try it again, regardless of the error situation
that prevented the hotunplug to occur. Of all the not so pretty
fixes/mitigations for CPU hotunplug errors in pSeries, timing out the
operation is an admission that we have no control in the process, and
must assume the worst case if the operation doesn't succeed in a
sensible time frame.

[1] https://lists.gnu.org/archive/html/qemu-devel/2021-01/msg03353.html
[2] https://lists.gnu.org/archive/html/qemu-devel/2021-01/msg04400.html

Reported-by: Xujun Ma <xuma@redhat.com>
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1911414
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210222194531.62717-5-danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-03-10 09:07:09 +11:00
..
acpi acpi/core: always set SCI_EN when SMM isn't supported 2021-02-23 10:58:42 -05:00
adc hw/adc: Add an ADC module for NPCM7XX 2021-01-12 21:19:02 +00:00
arm hw/arm/mps2: Update old infocenter.arm.com URLs 2021-03-08 11:54:16 +00:00
audio qom: Put name parameter before value / visitor parameter 2020-07-10 15:18:08 +02:00
block qdev: Move softmmu properties to qdev-properties-system.h 2020-12-18 15:20:17 -05:00
char hw/char/pl011: add a clock input 2020-10-27 11:10:44 +00:00
core accel/tcg: Precompute curr_cflags into cpu->tcg_cflags 2021-03-06 11:53:57 -08:00
cpu Use OBJECT_DECLARE_SIMPLE_TYPE when possible 2020-09-18 14:12:32 -04:00
cris sysbus: Convert to sysbus_realize() etc. with Coccinelle 2020-06-15 22:05:28 +02:00
display Clean up includes 2020-12-10 17:16:44 +01:00
dma arm: Update infocenter.arm.com URLs 2021-02-11 11:50:14 +00:00
firmware machine: Refactor smp-related call chains to pass MachineState 2019-07-05 17:07:36 -03:00
gpio hw/gpio: Add GPIO model for Nuvoton NPCM7xx 2020-10-27 11:10:32 +00:00
hyperv Use OBJECT_DECLARE_SIMPLE_TYPE when possible 2020-09-18 14:12:32 -04:00
i2c hw/i2c: Implement NPCM7XX SMBus Module FIFO Mode 2021-02-16 14:12:54 +00:00
i386 i386/acpi: restore device paths for pre-5.1 vms 2021-03-02 05:40:35 -05:00
ide nomaintainer: Fix Lesser GPL version number 2020-11-15 17:04:40 +01:00
input input: tsc2xxx fix. 2020-09-22 21:11:10 +01:00
intc hw/ppc: Remove unused ppcuic_init() 2021-01-19 10:20:29 +11:00
ipack Use OBJECT_DECLARE_SIMPLE_TYPE when possible 2020-09-18 14:12:32 -04:00
ipmi Use OBJECT_DECLARE_SIMPLE_TYPE when possible 2020-09-18 14:12:32 -04:00
isa vt82c686: Make vt82c686b-pm an abstract base class and add vt8231-pm based on it 2021-02-21 19:42:34 +01:00
kvm target/i386: always create kvmclock device 2020-09-30 19:11:36 +02:00
lm32 Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
m68k hw/m68k/next-cube: Add missing header comment to next-cube.h 2021-01-19 09:11:52 +01:00
mem acpi: Permit OEM ID and OEM table ID fields to be changed 2021-02-05 08:52:59 -05:00
mips hw/mips: Add a bootloader helper 2021-02-21 18:41:04 +01:00
misc hw/arm/mps2: Update old infocenter.arm.com URLs 2021-03-08 11:54:16 +00:00
net hw/net: Add npcm7xx emc model 2021-03-05 15:17:34 +00:00
nubus Use OBJECT_DECLARE_SIMPLE_TYPE when possible 2020-09-18 14:12:32 -04:00
nvram fw_cfg: Refactor extra pci roots addition 2020-12-08 13:48:57 -05:00
pci vt82c686: Make vt82c686b-pm an abstract base class and add vt8231-pm based on it 2021-02-21 19:42:34 +01:00
pci-bridge Use OBJECT_DECLARE_SIMPLE_TYPE when possible 2020-09-18 14:12:32 -04:00
pci-host Pull request 2021-02-10 15:42:20 +00:00
ppc spapr_drc.c: add hotunplug timeout for CPUs 2021-03-10 09:07:09 +11:00
rdma Use DECLARE_*CHECKER* macros 2020-09-09 09:27:09 -04:00
remote multi-process: perform device reset in the remote process 2021-02-10 09:23:28 +00:00
riscv hw/riscv: sifive_u: Change SIFIVE_U_GEM_IRQ to decimal value 2021-03-04 09:43:29 -05:00
rtc m48t59: remove legacy m48t59_init() function 2020-10-18 16:21:42 +01:00
rx Use DECLARE_*CHECKER* macros 2020-09-09 09:27:09 -04:00
s390x s390: Recognize confidential-guest-support option 2021-02-08 16:57:38 +11:00
scsi qemu-sparc queue 2021-03-09 13:50:35 +00:00
sd Pull request trivial patches 20210220 2021-02-21 12:12:18 +00:00
semihosting semihosting: Fix Lesser GPL version number 2020-11-15 16:38:03 +01:00
sh4 hw/sh4: Add missing license 2021-03-06 16:18:42 +01:00
southbridge Use DECLARE_*CHECKER* macros 2020-09-09 09:27:09 -04:00
sparc include/hw/sparc/grlib.h: Remove unused set_pil_in_fn typedef 2021-01-06 11:41:37 +00:00
ssi hw/ssi: Add SiFive SPI controller support 2021-03-04 09:43:29 -05:00
timer arm: Remove frq properties on CMSDK timer, dualtimer, watchdog, ARMSSE 2021-01-29 15:54:44 +00:00
tricore Include hw/irq.h a lot less 2019-08-16 13:31:52 +02:00
unicore32 hw/unicore32: restrict hw addr defines to source file 2017-12-18 17:07:02 +03:00
usb usb: xlnx-usb-subsystem: Add xilinx usb subsystem 2020-12-15 12:04:30 +00:00
vfio vfio: Change default dirty pages tracking behavior during migration 2020-11-23 10:05:58 -07:00
virtio display/ui: add a callback to indicate GL state is flushed 2021-02-04 15:58:54 +01:00
watchdog arm: Remove frq properties on CMSDK timer, dualtimer, watchdog, ARMSSE 2021-01-29 15:54:44 +00:00
xen xen: remove GNUC check 2020-12-15 12:53:13 -05:00
xtensa Include hw/irq.h a lot less 2019-08-16 13:31:52 +02:00
boards.h confidential guest support: Rework the "memory-encryption" property 2021-02-08 16:57:38 +11:00
clock.h clock: Add new clock_has_source() function 2021-01-29 15:54:42 +00:00
elf_ops.h elf_ops: correct loading of 32 bit PVH kernel 2021-03-06 11:41:54 +01:00
fw-path-provider.h Use DECLARE_*CHECKER* macros 2020-09-09 09:27:09 -04:00
hotplug.h Use DECLARE_*CHECKER* macros 2020-09-09 09:27:09 -04:00
hw.h Include hw/hw.h exactly where needed 2019-08-16 13:31:52 +02:00
ide.h hw/ide: Move MAX_IDE_DEVS define to hw/ide/internal.h 2020-03-17 12:22:36 -04:00
irq.h include/hw/irq.h: New function qemu_irq_is_connected() 2020-08-03 17:55:03 +01:00
loader-fit.h nomaintainer: Fix Lesser GPL version number 2020-11-15 17:04:40 +01:00
loader.h hw/core/loader: Let load_elf() populate a field with CPU-specific flags 2020-01-29 19:28:52 +01:00
nmi.h Use DECLARE_*CHECKER* macros 2020-09-09 09:27:09 -04:00
or-irq.h Use DECLARE_*CHECKER* macros 2020-09-09 09:27:09 -04:00
pcmcia.h Use OBJECT_DECLARE_TYPE when possible 2020-09-18 14:12:32 -04:00
platform-bus.h nomaintainer: Fix Lesser GPL version number 2020-11-15 17:04:40 +01:00
ptimer.h ptimer: Add new ptimer_set_period_from_clock() function 2021-01-29 15:54:42 +00:00
qdev-clock.h hw/qdev-clock: Avoid calling qdev_connect_clock_in after DeviceRealize 2020-08-28 10:02:46 +01:00
qdev-core.h machine: introduce MachineInitPhase 2020-12-15 12:51:52 -05:00
qdev-dma.h Supply missing header guards 2019-06-12 13:20:21 +02:00
qdev-properties-system.h qdev: Reuse DEFINE_PROP in all DEFINE_PROP_* macros 2020-12-18 15:20:17 -05:00
qdev-properties.h qdev: Rename qdev_get_prop_ptr() to object_field_prop_ptr() 2020-12-18 15:20:18 -05:00
register.h Use DECLARE_*CHECKER* macros 2020-09-09 09:27:09 -04:00
registerfields.h hw/registerfields: Prefix local variables with underscore in macros 2020-05-27 11:23:07 -07:00
resettable.h Use DECLARE_*CHECKER* macros 2020-09-09 09:27:09 -04:00
stream.h hw/core/stream: Rename StreamSlave as StreamSink 2020-12-10 12:15:04 -05:00
sysbus.h qom: Remove module_obj_name parameter from OBJECT_DECLARE* macros 2020-09-18 14:12:32 -04:00
usb.h usb: add pcap support. 2021-01-22 14:51:35 +01:00
vmstate-if.h Use DECLARE_*CHECKER* macros 2020-09-09 09:27:09 -04:00