Cc'ing David
On Tue, 23 Mar 2021 17:48:36 +0100
Thomas Huth <th...@redhat.com> wrote:
>
> In case anyone is interested in fixing those, there are two regressions with
> qemu-system-ppc64 in the current master branch:
>
> $ ./qemu-system-ppc64 -M ppce500 -device macio-oldworld
> qemu-system-ppc64: ../../devel/qemu/softmmu/memory.c:2443:
> memory_region_add_subregion_common: Assertion `!subregion->container' failed.
>
> $ ./qemu-system-ppc64 -device power8_v2.0-spapr-cpu-core,help
> /home/thuth/devel/qemu/include/hw/boards.h:24:MACHINE: Object 0x5635bd53af10
> is not an instance of type machine
> Aborted (core dumped)
>
I've bisected this one to:
3df261b6676b5850e93d6fab3f7a98f8ee8f19c5 is the first bad commit
commit 3df261b6676b5850e93d6fab3f7a98f8ee8f19c5
Author: Peter Maydell <peter.mayd...@linaro.org>
Date: Fri Mar 13 17:24:47 2020 +0000
softmmu/vl.c: Handle '-cpu help' and '-device help' before 'no default
machine'
Currently if you try to ask for the list of CPUs for a target
architecture which does not specify a default machine type
you just get an error:
$ qemu-system-arm -cpu help
qemu-system-arm: No machine specified, and there is no default
Use -machine help to list supported machines
Since the list of CPUs doesn't depend on the machine, this is
unnecessarily unhelpful. "-device help" has a similar problem.
Move the checks for "did the user ask for -cpu help or -device help"
up so they precede the select_machine() call which checks that the
user specified a valid machine type.
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
softmmu/vl.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
bisect run success
This change is fine but it unveils a bad assumption.
0 0x00007ffff64a3708 in raise () at /lib64/power9/libc.so.6
#1 0x00007ffff6483bcc in abort () at /lib64/power9/libc.so.6
#2 0x00000001008db940 in object_dynamic_cast_assert
(obj=0x10126f670, typename=0x100c20380 "machine", file=0x100b34878
"/home/greg/Work/qemu/qemu-ppc/include/hw/boards.h", line=<optimized out>,
func=0x100bcd320 <__func__.30338> "MACHINE") at ../../qom/object.c:883
#3 0x0000000100456e00 in MACHINE (obj=<optimized out>) at
/home/greg/Work/qemu/qemu-ppc/include/hw/boards.h:24
#4 0x0000000100456e00 in cpu_core_instance_init (obj=0x10118e2c0) at
../../hw/cpu/core.c:69
#5 0x00000001008d9f44 in object_init_with_type (obj=obj@entry=0x10118e2c0,
ti=0x1011fd470) at ../../qom/object.c:375
#6 0x00000001008d9f24 in object_init_with_type (obj=obj@entry=0x10118e2c0,
ti=0x101211ad0) at ../../qom/object.c:371
#7 0x00000001008d9f24 in object_init_with_type (obj=obj@entry=0x10118e2c0,
ti=ti@entry=0x101212760) at ../../qom/object.c:371
#8 0x00000001008dc474 in object_initialize_with_type
(obj=obj@entry=0x10118e2c0, size=size@entry=160, type=type@entry=0x101212760)
at ../../qom/object.c:517
#9 0x00000001008dc678 in object_new_with_type (type=0x101212760) at
../../qom/object.c:732
#10 0x00000001009fbad8 in qmp_device_list_properties (typename=<optimized out>,
errp=<optimized out>) at ../../qom/qom-qmp-cmds.c:146
#11 0x00000001005a4bf0 in qdev_device_help (opts=0x10126c200) at
../../softmmu/qdev-monitor.c:285
#12 0x0000000100760afc in device_help_func (opaque=<optimized out>,
opts=<optimized out>, errp=<optimized out>) at ../../softmmu/vl.c:1204
#13 0x0000000100ad1050 in qemu_opts_foreach (list=<optimized out>,
func=0x100760ae0 <device_help_func>, opaque=0x0, errp=0x0) at
../../util/qemu-option.c:1167
#14 0x00000001007653cc in qemu_process_help_options () at
../../softmmu/vl.c:2451
#15 0x00000001007653cc in qemu_init (argc=<optimized out>, argv=<optimized
out>, envp=<optimized out>) at ../../softmmu/vl.c:3521
#16 0x00000001002f4f88 in main (argc=<optimized out>, argv=<optimized out>,
envp=<optimized out>) at ../../softmmu/main.c:49
Basically, "-device power8_v2.0-spapr-cpu-core,help" ends up
instantiating an object of the "power8_v2.0-spapr-cpu-core" type,
which derives from "cpu-core". The "cpu-core" type has an instance
init function that assumes that qdev_get_machine() returns an object
of type "machine"...
static void cpu_core_instance_init(Object *obj)
{
MachineState *ms = MACHINE(qdev_get_machine());
^^
...here.
qdev_get_machine() cannot return a valid machine type since
select_machine() hasn't been called yet... an instance init
function is probably not the best place to use qdev_get_machine()
if any.
CPUCore *core = CPU_CORE(obj);
core->nr_threads = ms->smp.threads;
}
It seems that this should rather sit in a device realize function,
when the machine type is known.
> Thomas
>
>
