Re: [Qemu-devel] [PATCH 03/11] pc: check if KVM has enough memory slots for DIMM devices

[Paolo Bonzini <pbonzini@redhat.com>]

On 31/10/2014 17:38, Igor Mammedov wrote:
> check amount of available KVM memory slots after all
> devices were initialized and exit with error if
> there isn't enough free memory slots for DIMMs.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---
>  hw/i386/pc.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
> 
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index f6dfd9b..41d91fb 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1125,6 +1125,36 @@ PcGuestInfo *pc_guest_info_init(ram_addr_t below_4g_mem_size,
>      return guest_info;
>  }
>  
> +static int pc_dimm_count(Object *obj, void *opaque)
> +{
> +    int *count = opaque;
> +
> +    if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
> +        (*count)++;
> +    }
> +
> +    object_child_foreach(obj, pc_dimm_count, opaque);
> +    return 0;
> +}
> +
> +static void pc_kvm_slot_check(Notifier *notifier, void *data)
> +{
> +    MachineState *ms = MACHINE(qdev_get_machine());
> +    int free_slots = kvm_free_slot_count(ms);
> +    int used_ram_slots = 0;
> +
> +    pc_dimm_count(OBJECT(ms), &used_ram_slots);
> +    if ((ms->ram_slots - used_ram_slots) > free_slots) {
> +        error_report("KVM doesn't support more than %d memory slots",
> +                     kvm_free_slot_count(ms));
> +        exit(EXIT_FAILURE);
> +    }
> +}
> +
> +static Notifier kvm_slot_check_on_machine_done = {
> +                        .notify = pc_kvm_slot_check
> +                     };
> +
>  /* setup pci memory address space mapping into system address space */
>  void pc_pci_as_mapping_init(Object *owner, MemoryRegion *system_memory,
>                              MemoryRegion *pci_address_space)
> @@ -1269,6 +1299,8 @@ FWCfgState *pc_memory_init(MachineState *machine,
>                             "hotplug-memory", hotplug_mem_size);
>          memory_region_add_subregion(system_memory, pcms->hotplug_memory_base,
>                                      &pcms->hotplug_memory);
> +
> +        qemu_add_machine_init_done_notifier(&kvm_slot_check_on_machine_done);
>      }
>  
>      /* Initialize PC system firmware */
> 

This will always be off by 4 or so due to system RAM and ROM slots.  I
think patch 1 is enough.

Paolo