Re: [Qemu-devel] [PATCH v2 1/6] machine: Replace has_dynamic_sysbus with list of allowed devices

[Marcel Apfelbaum <marcel@redhat.com>]

On 25/11/2017 17:16, Eduardo Habkost wrote:
> The existing has_dynamic_sysbus flag makes the machine accept
> every user-creatable sysbus device type on the command-line.
> Replace it with a list of allowed device types, so machines can
> easily accept some sysbus devices while rejecting others.
> 
> To keep exactly the same behavior as before, the existing
> has_dynamic_sysbus=true assignments are replaced with a
> TYPE_SYS_BUS_DEVICE entry on the allowed list.  Other patches
> will replace the TYPE_SYS_BUS_DEVICE entries with more specific
> lists of devices.
> 
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Cc: Marcel Apfelbaum <marcel@redhat.com>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Alexander Graf <agraf@suse.de>
> Cc: David Gibson <david@gibson.dropbear.id.au>
> Cc: Stefano Stabellini <sstabellini@kernel.org>
> Cc: Anthony Perard <anthony.perard@citrix.com>
> Cc: qemu-arm@nongnu.org
> Cc: qemu-ppc@nongnu.org
> Cc: xen-devel@lists.xenproject.org
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
> Changes v1 -> v2:
> * Replace "dynamic sysbus whitelist" with "allowed sysbus devices"
> * Simply add TYPE_SYS_BUS_DEVICE to the list on existing
>    has_dynamic_sysbus=true machines, and make machine-types more
>    strict in separate patches
> ---
>   include/hw/boards.h  |  5 ++++-
>   hw/arm/virt.c        |  3 ++-
>   hw/core/machine.c    | 43 +++++++++++++++++++++++++++++--------------
>   hw/i386/pc_q35.c     |  3 ++-
>   hw/ppc/e500plat.c    |  4 +++-
>   hw/ppc/spapr.c       |  3 ++-
>   hw/xen/xen_backend.c |  7 ++++++-
>   7 files changed, 48 insertions(+), 20 deletions(-)
> 
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 156b16f7a6..041bc08971 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -76,6 +76,9 @@ void machine_set_cpu_numa_node(MachineState *machine,
>                                  const CpuInstanceProperties *props,
>                                  Error **errp);
>   
> +void machine_class_allow_dynamic_sysbus_dev(MachineClass *mc, const char *type);
> +
> +
>   /**
>    * CPUArchId:
>    * @arch_id - architecture-dependent CPU ID of present or possible CPU
> @@ -179,7 +182,6 @@ struct MachineClass {
>           no_floppy:1,
>           no_cdrom:1,
>           no_sdcard:1,
> -        has_dynamic_sysbus:1,
>           pci_allow_0_address:1,
>           legacy_fw_cfg_order:1;
>       int is_default;
> @@ -197,6 +199,7 @@ struct MachineClass {
>       bool ignore_memory_transaction_failures;
>       int numa_mem_align_shift;
>       const char **valid_cpu_types;
> +    strList *allowed_dynamic_sysbus_devices;
>       bool auto_enable_numa_with_memhp;
>       void (*numa_auto_assign_ram)(MachineClass *mc, NodeInfo *nodes,
>                                    int nb_nodes, ram_addr_t size);
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 9e18b410d7..fa6dc15fcd 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -1591,7 +1591,8 @@ static void virt_machine_class_init(ObjectClass *oc, void *data)
>        * configuration of the particular instance.
>        */
>       mc->max_cpus = 255;
> -    mc->has_dynamic_sysbus = true;
> +    /*TODO: allow only sysbus devices that really work with this machine */
> +    machine_class_allow_dynamic_sysbus_dev(mc, TYPE_SYS_BUS_DEVICE);
>       mc->block_default_type = IF_VIRTIO;
>       mc->no_cdrom = 1;
>       mc->pci_allow_0_address = true;
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index 36c2fb069c..ab2ec292f3 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -335,29 +335,44 @@ static bool machine_get_enforce_config_section(Object *obj, Error **errp)
>       return ms->enforce_config_section;
>   }
>   
> -static void error_on_sysbus_device(SysBusDevice *sbdev, void *opaque)
> +void machine_class_allow_dynamic_sysbus_dev(MachineClass *mc, const char *type)
>   {
> -    error_report("Option '-device %s' cannot be handled by this machine",
> -                 object_class_get_name(object_get_class(OBJECT(sbdev))));
> -    exit(1);
> +    strList *item = g_new0(strList, 1);
> +
> +    item->value = g_strdup(type);
> +    item->next = mc->allowed_dynamic_sysbus_devices;
> +    mc->allowed_dynamic_sysbus_devices = item;
>   }
>   
> -static void machine_init_notify(Notifier *notifier, void *data)
> +static void validate_sysbus_device(SysBusDevice *sbdev, void *opaque)
>   {
> -    Object *machine = qdev_get_machine();
> -    ObjectClass *oc = object_get_class(machine);
> -    MachineClass *mc = MACHINE_CLASS(oc);
> +    MachineState *machine = opaque;
> +    MachineClass *mc = MACHINE_GET_CLASS(machine);
> +    bool allowed = false;
> +    strList *wl;
>   
> -    if (mc->has_dynamic_sysbus) {
> -        /* Our machine can handle dynamic sysbus devices, we're all good */
> -        return;
> +    for (wl = mc->allowed_dynamic_sysbus_devices;
> +         !allowed && wl;
> +         wl = wl->next) {
> +        allowed |= !!object_dynamic_cast(OBJECT(sbdev), wl->value);
>       }
>   
> +    if (!allowed) {
> +        error_report("Option '-device %s' cannot be handled by this machine",
> +                     object_class_get_name(object_get_class(OBJECT(sbdev))));
> +        exit(1);
> +    }
> +}
> +
> +static void machine_init_notify(Notifier *notifier, void *data)
> +{
> +    MachineState *machine = MACHINE(qdev_get_machine());
> +
>       /*
> -     * Loop through all dynamically created devices and check whether there
> -     * are sysbus devices among them. If there are, error out.
> +     * Loop through all dynamically created sysbus devices and check if they are
> +     * all allowed.  If a device is not allowed, error out.
>        */
> -    foreach_dynamic_sysbus_device(error_on_sysbus_device, NULL);
> +    foreach_dynamic_sysbus_device(validate_sysbus_device, machine);
>   }
>   
>   HotpluggableCPUList *machine_query_hotpluggable_cpus(MachineState *machine)
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index d6060043ac..d0b0e5b422 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -299,7 +299,8 @@ 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;
> +    /*TODO: allow only sysbus devices that really work with this machine */
> +    machine_class_allow_dynamic_sysbus_dev(m, TYPE_SYS_BUS_DEVICE);
>       m->max_cpus = 288;
>   }
>   
> diff --git a/hw/ppc/e500plat.c b/hw/ppc/e500plat.c
> index e59e80fb9e..438118c29b 100644
> --- a/hw/ppc/e500plat.c
> +++ b/hw/ppc/e500plat.c
> @@ -15,6 +15,7 @@
>   #include "hw/boards.h"
>   #include "sysemu/device_tree.h"
>   #include "sysemu/kvm.h"
> +#include "hw/sysbus.h"
>   #include "hw/pci/pci.h"
>   #include "hw/ppc/openpic.h"
>   #include "kvm_ppc.h"
> @@ -63,7 +64,8 @@ static void e500plat_machine_init(MachineClass *mc)
>       mc->desc = "generic paravirt e500 platform";
>       mc->init = e500plat_init;
>       mc->max_cpus = 32;
> -    mc->has_dynamic_sysbus = true;
> +    /*TODO: allow only sysbus devices that really work with this machine */
> +    machine_class_allow_dynamic_sysbus_dev(mc, TYPE_SYS_BUS_DEVICE);
>       mc->default_cpu_type = POWERPC_CPU_TYPE_NAME("e500v2_v30");
>   }
>   
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index d682f013d4..82040cc5d1 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -3603,7 +3603,8 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
>       mc->default_boot_order = "";
>       mc->default_ram_size = 512 * M_BYTE;
>       mc->kvm_type = spapr_kvm_type;
> -    mc->has_dynamic_sysbus = true;
> +    /*TODO: allow only sysbus devices that really work with this machine */
> +    machine_class_allow_dynamic_sysbus_dev(mc, TYPE_SYS_BUS_DEVICE);
>       mc->pci_allow_0_address = true;
>       mc->get_hotplug_handler = spapr_get_hotplug_handler;
>       hc->pre_plug = spapr_machine_device_pre_plug;
> diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c
> index 0f849a26d2..82380ea9ee 100644
> --- a/hw/xen/xen_backend.c
> +++ b/hw/xen/xen_backend.c
> @@ -564,7 +564,12 @@ static void xen_set_dynamic_sysbus(void)
>       ObjectClass *oc = object_get_class(machine);
>       MachineClass *mc = MACHINE_CLASS(oc);
>   
> -    mc->has_dynamic_sysbus = true;
> +    /*
> +     * Emulate old mc->has_dynamic_sysbus=true assignment
> +     *
> +     *TODO: add only Xen devices to the list
> +     */
> +    machine_class_allow_dynamic_sysbus_dev(mc, TYPE_SYS_BUS_DEVICE);
>   }
>   
>   int xen_be_register(const char *type, struct XenDevOps *ops)
> 

Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>

Thanks,
Marcel