Re: [Qemu-devel] [PATCH v2 3/3] q35: allow dynamic sysbus

[Markus Armbruster <armbru@redhat.com>]

Marcel Apfelbaum <marcel@redhat.com> writes:

> Allow adding sysbus devices with -device on Q35.
>
> At first Q35 will support only intel-iommu to be added this way,
> however the command line will support all sysbus devices.
>
> Mark with 'cannot_instantiate_with_device_add_yet' the ones
> causing immediate problems (e.g. crashes).
>
> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
> ---
>  hw/i386/pc_q35.c                    | 1 +
>  hw/pci-bridge/pci_expander_bridge.c | 1 +
>  hw/pci-host/piix.c                  | 1 +
>  hw/pci-host/q35.c                   | 1 +
>  4 files changed, 4 insertions(+)
>
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index 04aae89..431eaed 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -281,6 +281,7 @@ static void pc_q35_machine_options(MachineClass *m)
>      m->default_machine_opts = "firmware=bios-256k.bin";
>      m->default_display = "std";
>      m->no_floppy = 1;
> +    m->has_dynamic_sysbus = true;
>  }
>  
>  static void pc_q35_2_6_machine_options(MachineClass *m)
> diff --git a/hw/pci-bridge/pci_expander_bridge.c b/hw/pci-bridge/pci_expander_bridge.c
> index ba320bd..40518a2 100644
> --- a/hw/pci-bridge/pci_expander_bridge.c
> +++ b/hw/pci-bridge/pci_expander_bridge.c
> @@ -149,6 +149,7 @@ static void pxb_host_class_init(ObjectClass *class, void *data)
>      PCIHostBridgeClass *hc = PCI_HOST_BRIDGE_CLASS(class);
>  
>      dc->fw_name = "pci";
> +    dc->cannot_instantiate_with_device_add_yet = true;
>      sbc->explicit_ofw_unit_address = pxb_host_ofw_unit_address;
>      hc->root_bus_path = pxb_host_root_bus_path;
>  }

Any assignment to cannot_instantiate_with_device_add_yet must have a
comment, like this:

       /* Reason: frobnicates some frobs backwards */
       dc->cannot_instantiate_with_device_add_yet = true;

We have one offender in master: hw/ppc/spapr_pci.c (commit 09aa9a52),
which I'll try to get fixed.  Please don't add more.

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