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Re: [Qemu-block] [Qemu-devel] [RFC PATCH 4/6] sysbus: Fix latent bug wit
From: |
Marc-André Lureau |
Subject: |
Re: [Qemu-block] [Qemu-devel] [RFC PATCH 4/6] sysbus: Fix latent bug with onboard devices |
Date: |
Tue, 26 Feb 2019 13:48:00 +0100 |
Hi
On Mon, Feb 25, 2019 at 7:40 PM Markus Armbruster <address@hidden> wrote:
>
> The first call of sysbus_get_default() creates the main system bus and
> stores it in QOM as "/machine/unattached/sysbus". This must not
> happen before main() creates "/machine", or else container_get() would
> "helpfully" create it as "container" object, and the real creation of
> "/machine" would later abort with "attempt to add duplicate property
> 'machine' to object (type 'container')". Has been that way ever since
> we wired up busses in QOM (commit f968fc6892d, v1.2.0).
>
> I believe the bug is latent. I got it to bite by trying to
> qdev_create() a sysbus device from a machine's .instance_init()
> method.
>
> The fix is obvious: store the main system bus in QOM right after
> creating "/machine".
>
> Signed-off-by: Markus Armbruster <address@hidden>
makes sense to me, but I might miss some subtleties..
Reviewed-by: Marc-André Lureau <address@hidden>
> ---
> hw/core/sysbus.c | 3 ---
> vl.c | 4 ++++
> 2 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/hw/core/sysbus.c b/hw/core/sysbus.c
> index 9f9edbcab9..307cf90a51 100644
> --- a/hw/core/sysbus.c
> +++ b/hw/core/sysbus.c
> @@ -357,9 +357,6 @@ static void main_system_bus_create(void)
> qbus_create_inplace(main_system_bus, system_bus_info.instance_size,
> TYPE_SYSTEM_BUS, NULL, "main-system-bus");
> OBJECT(main_system_bus)->free = g_free;
> - object_property_add_child(container_get(qdev_get_machine(),
> - "/unattached"),
> - "sysbus", OBJECT(main_system_bus), NULL);
> }
>
> BusState *sysbus_get_default(void)
> diff --git a/vl.c b/vl.c
> index e3fdce410f..6ce3d2d448 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -3990,6 +3990,10 @@ int main(int argc, char **argv, char **envp)
> }
> object_property_add_child(object_get_root(), "machine",
> OBJECT(current_machine), &error_abort);
> + object_property_add_child(container_get(OBJECT(current_machine),
> + "/unattached"),
> + "sysbus", OBJECT(sysbus_get_default()),
> + NULL);
>
> if (machine_class->minimum_page_bits) {
> if
> (!set_preferred_target_page_bits(machine_class->minimum_page_bits)) {
> --
> 2.17.2
>
>
--
Marc-André Lureau
- [Qemu-block] [RFC PATCH 0/6] pc: Support firmware configuration with -blockdev, Markus Armbruster, 2019/02/25
- [Qemu-block] [RFC PATCH 5/6] vl: Create block backends before setting machine properties, Markus Armbruster, 2019/02/25
- [Qemu-block] [RFC PATCH 4/6] sysbus: Fix latent bug with onboard devices, Markus Armbruster, 2019/02/25
- Re: [Qemu-block] [Qemu-devel] [RFC PATCH 4/6] sysbus: Fix latent bug with onboard devices,
Marc-André Lureau <=
- [Qemu-block] [RFC PATCH 3/6] vl: Fix latent bug with -global and onboard devices, Markus Armbruster, 2019/02/25
- [Qemu-block] [RFC PATCH 1/6] qdev: Fix latent bug with compat_props and onboard devices, Markus Armbruster, 2019/02/25
- [Qemu-block] [RFC PATCH 2/6] qom: Move compat_props machinery from qdev to QOM, Markus Armbruster, 2019/02/25
- [Qemu-block] [RFC PATCH 6/6] pc: Support firmware configuration with -blockdev, Markus Armbruster, 2019/02/25