On Mon, Mar 16, 2015 at 06:33:52PM +0100, Markus Armbruster wrote:
> Doesn't work since commit 31bed55 changed qdev_device_help() to reject
> abstract devices and devices that have
> cannot_instantiate_with_device_add_yet set.
>
> The former makes sense: abstract devices are purely internal, and the
> implementation of the help feature can't cope with them.
>
> The latter makes less sense: the implementation works fine, and even
> though you can't -device such a device, the help may still be useful
> elsewhere, for instance with -global.
>
> Revert the latter by moving the cannot_instantiate_with_device_add_yet
> check back to the other caller of qdev_get_device_class(),
> qdev_device_add().
This reintroduces the following crash:
$ ./x86_64-softmmu/qemu-system-x86_64 -device host-x86_64-cpu,help
qemu-system-x86_64: /home/ehabkost/rh/proj/virt/qemu/target-i386/cpu.c:1391:
host_x86_cpu_initfn: Assertion `(kvm_allowed)' failed.
Aborted (core dumped)
And this (which is not x86-specific because other arches also call
cpu_exec_init() inside instance_init):
$ ./x86_64-softmmu/qemu-system-x86_64 -monitor stdio
QEMU 2.2.50 monitor - type 'help' for more information
(qemu) device_add Nehalem-x86_64-cpu,help
Nehalem-x86_64-cpu.filtered-features=X86CPUFeatureWordInfo
Nehalem-x86_64-cpu.feature-words=X86CPUFeatureWordInfo
Nehalem-x86_64-cpu.apic-id=int
Nehalem-x86_64-cpu.tsc-frequency=int
Nehalem-x86_64-cpu.model-id=string
Nehalem-x86_64-cpu.vendor=string
Nehalem-x86_64-cpu.xlevel=int
Nehalem-x86_64-cpu.level=int
Nehalem-x86_64-cpu.stepping=int
Nehalem-x86_64-cpu.model=int
Nehalem-x86_64-cpu.family=int
Nehalem-x86_64-cpu.kvm=bool
Nehalem-x86_64-cpu.enforce=bool
Nehalem-x86_64-cpu.check=bool
Nehalem-x86_64-cpu.hv-time=bool
Nehalem-x86_64-cpu.hv-vapic=bool
Nehalem-x86_64-cpu.hv-relaxed=bool
Nehalem-x86_64-cpu.hv-spinlocks=int
Nehalem-x86_64-cpu.pmu=bool
(qemu) Segmentation fault (core dumped)
Should we:
1) Live with the crashes until we move all code with side-effects outside
instance_init (including bot not limited to cpu_exec_init() calls on most
CPU classes);
2) add a "instance_init_is_unsafe" flag to those classes classes; or
3) Keep the current code until we fix the classes that have unsafe
instance_init functions?
>
> Signed-off-by: Markus Armbruster <arm...@redhat.com>
> ---
> qdev-monitor.c | 22 ++++++++++++----------
> 1 file changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/qdev-monitor.c b/qdev-monitor.c
> index 5d30ac5..b0b8cf1 100644
> --- a/qdev-monitor.c
> +++ b/qdev-monitor.c
> @@ -180,10 +180,14 @@ static const char *find_typename_by_alias(const char
> *alias)
> return NULL;
> }
>
> +
> +/**
> + * Return DeviceClass for concrete device type @driver.
> + * On error, store an error through @errp if non-null, and return %NULL.
> + */
> static DeviceClass *qdev_get_device_class(const char **driver, Error **errp)
> {
> ObjectClass *oc;
> - DeviceClass *dc;
>
> oc = object_class_by_name(*driver);
> if (!oc) {
> @@ -206,15 +210,7 @@ static DeviceClass *qdev_get_device_class(const char
> **driver, Error **errp)
> return NULL;
> }
>
> - dc = DEVICE_CLASS(oc);
> - if (dc->cannot_instantiate_with_device_add_yet ||
> - (qdev_hotplug && !dc->hotpluggable)) {
> - error_set(errp, QERR_INVALID_PARAMETER_VALUE, "driver",
> - "pluggable device type");
> - return NULL;
> - }
> -
> - return dc;
> + return DEVICE_CLASS(oc);
> }
>
>
> @@ -512,6 +508,12 @@ DeviceState *qdev_device_add(QemuOpts *opts)
> error_free(err);
> return NULL;
> }
> + if (dc->cannot_instantiate_with_device_add_yet ||
> + (qdev_hotplug && !dc->hotpluggable)) {
> + qerror_report(QERR_INVALID_PARAMETER_VALUE, "driver",
> + "pluggable device type");
> + return NULL;
> + }
>
> /* find bus */
> path = qemu_opt_get(opts, "bus");
> --
> 1.9.3
>
--
Eduardo
