qemu/hw/char
Daniel Henrique Barboza fb06411210 qmp hmp: Make system_wakeup check wake-up support and run state
The qmp/hmp command 'system_wakeup' is simply a direct call to
'qemu_system_wakeup_request' from vl.c. This function verifies if
runstate is SUSPENDED and if the wake up reason is valid before
proceeding. However, no error or warning is thrown if any of those
pre-requirements isn't met. There is no way for the caller to
differentiate between a successful wakeup or an error state caused
when trying to wake up a guest that wasn't suspended.

This means that system_wakeup is silently failing, which can be
considered a bug. Adding error handling isn't an API break in this
case - applications that didn't check the result will remain broken,
the ones that check it will have a chance to deal with it.

Adding to that, the commit before previous created a new QMP API called
query-current-machine, with a new flag called wakeup-suspend-support,
that indicates if the guest has the capability of waking up from suspended
state. Although such guest will never reach SUSPENDED state and erroring
it out in this scenario would suffice, it is more informative for the user
to differentiate between a failure because the guest isn't suspended versus
a failure because the guest does not have support for wake up at all.

All this considered, this patch changes qmp_system_wakeup to check if
the guest is capable of waking up from suspend, and if it is suspended.
After this patch, this is the output of system_wakeup in a guest that
does not have wake-up from suspend support (ppc64):

(qemu) system_wakeup
wake-up from suspend is not supported by this guest
(qemu)

And this is the output of system_wakeup in a x86 guest that has the
support but isn't suspended:

(qemu) system_wakeup
Unable to wake up: guest is not in suspended state
(qemu)

Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20181205194701.17836-4-danielhb413@gmail.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2018-12-18 07:55:47 +01:00
..
Makefile.objs hw/char: Implement nRF51 SoC UART 2018-11-02 14:03:33 +00:00
bcm2835_aux.c bcm2835_aux: Swap RX and TX interrupt assignments 2018-07-16 17:18:42 +01:00
cadence_uart.c maint: Fix macros with broken 'do/while(0); ' usage 2018-01-16 14:54:52 +01:00
cmsdk-apb-uart.c hw/char/cmsdk-apb-uart.c: Accept more input after character read 2018-05-04 18:05:50 +01:00
debugcon.c misc: drop old i386 dependency 2017-12-18 17:07:03 +03:00
digic-uart.c hw/digic: Add trailing '\n' to qemu_log() calls 2018-06-08 13:15:33 +01:00
escc.c hw/char: remove legacy interface escc_init() 2018-02-16 12:14:26 +11:00
etraxfs_ser.c char: add backend hotswap handler 2017-07-14 11:04:33 +02:00
exynos4210_uart.c hw/char/exynos4210_uart.c: Remove unneeded handling of NULL chardev 2018-04-26 13:57:00 +01:00
grlib_apbuart.c char/grlib_apbuart: Convert sysbus init function to realize function 2018-12-13 13:47:57 +00:00
imx_serial.c imx_serial: Generate interrupt on receive data ready if enabled 2018-08-20 11:24:31 +01:00
ipoctal232.c char: avoid chardevice direct access 2017-07-14 11:04:33 +02:00
lm32_juart.c char: add backend hotswap handler 2017-07-14 11:04:33 +02:00
lm32_uart.c char: add backend hotswap handler 2017-07-14 11:04:33 +02:00
mcf_uart.c hw: Do not include "exec/address-spaces.h" if it is not necessary 2018-06-01 14:15:10 +02:00
milkymist-uart.c char: add backend hotswap handler 2017-07-14 11:04:33 +02:00
nrf51_uart.c hw/char: Implement nRF51 SoC UART 2018-11-02 14:03:33 +00:00
omap_uart.c chardev: move headers to include/chardev 2017-06-02 11:33:52 +04:00
parallel-isa.c hw/isa: Move parallel_hds_isa_init() to hw/char/parallel-isa.c 2018-03-12 16:12:47 +01:00
parallel.c hw/char/parallel: Convert from pdebug() macro to trace events 2018-06-29 15:04:18 +01:00
pl011.c char: add backend hotswap handler 2017-07-14 11:04:33 +02:00
sclpconsole-lm.c s390x/sclp: clean up sclp masks 2018-03-08 15:49:23 +01:00
sclpconsole.c s390x/sclp: clean up sclp masks 2018-03-08 15:49:23 +01:00
serial-isa.c serial-isa: Use MAX_ISA_SERIAL_PORTS instead of MAX_SERIAL_PORTS 2018-04-26 13:57:00 +01:00
serial-pci.c pci: Add INTERFACE_CONVENTIONAL_PCI_DEVICE to Conventional PCI devices 2017-10-15 05:54:43 +03:00
serial.c qmp hmp: Make system_wakeup check wake-up support and run state 2018-12-18 07:55:47 +01:00
sh_serial.c hw/char/sh_serial: Add timeout handling to unbreak serial input 2018-10-02 18:47:55 +02:00
spapr_vty.c spapr: Implement bug in spapr-vty device to be compatible with PowerVM 2017-11-22 15:28:37 +11:00
stm32f2xx_usart.c hw/arm/stm32f205: Fix the UART and Timer region size 2018-11-19 15:29:08 +00:00
terminal3270.c chardev: introduce qemu_chr_timeout_add_ms() 2018-01-12 13:22:02 +01:00
trace-events hw/char: Implement nRF51 SoC UART 2018-11-02 14:03:33 +00:00
virtio-console.c qapi: Drop qapi_event_send_FOO()'s Error ** argument 2018-08-28 18:21:38 +02:00
virtio-serial-bus.c virtio: do not take address of packed members 2018-10-02 19:09:13 +02:00
xen_console.c chardev: mark the calls that allow an implicit mux monitor 2018-10-03 14:45:05 +04:00
xilinx_uartlite.c char: add backend hotswap handler 2017-07-14 11:04:33 +02:00