Re: [Qemu-devel] [PATCH v1 1/5] machine: Add a valid_cpu_types property

[Eduardo Habkost <ehabkost@redhat.com>]

On Tue, Oct 03, 2017 at 01:05:09PM -0700, Alistair Francis wrote:
> This patch add a MachineClass element that can be set in the machine C
> code to specify a list of supported CPU types. If the supported CPU
> types are specified the user enter CPU (by -cpu at runtime) is checked
> against the supported types and QEMU exits if they aren't supported.
> 
> Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
> ---

Thanks!

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>

However, I will squash the following changes before queueing,
because:

* object_class_dynamic_cast() is safe even if class is NULL,
  so there's no need to validate cpu_type here.
* "must not be valid" sounds like the CPU is not allowed to be a
  valid CPU, so I rewrote the comment.


diff --git a/hw/core/machine.c b/hw/core/machine.c
index 3afc6a7b5b..36c2fb069c 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -766,9 +766,6 @@ void machine_run_board_init(MachineState *machine)
         ObjectClass *class = object_class_by_name(machine->cpu_type);
         int i;
 
-        /* machine->cpu_type is supposed to be always a valid QOM type */
-        assert(class);
-
         for (i = 0; machine_class->valid_cpu_types[i]; i++) {
             if (object_class_dynamic_cast(class,
                                           machine_class->valid_cpu_types[i])) {
@@ -780,7 +777,7 @@ void machine_run_board_init(MachineState *machine)
         }
 
         if (!machine_class->valid_cpu_types[i]) {
-            /* The user specified CPU must not be a valid CPU */
+            /* The user specified CPU is not valid */
             error_report("Invalid CPU type: %s", machine->cpu_type);
             error_printf("The valid types are: %s",
                          machine_class->valid_cpu_types[0]);
> 
> V1:
>  - Use 'type' in the error message
>  - Move a uneeded operation out of the for loop
>  - Remove the goto
> RFC v2:
>  - Rebase on Igor's cpu_type work
>  - Use object_class_dynamic_cast()
>  - Use a NULL terminated cahr** list
>  - Do the check before the machine_class init() is called
> 
> 
>  hw/core/machine.c   | 35 +++++++++++++++++++++++++++++++++++
>  include/hw/boards.h |  1 +
>  2 files changed, 36 insertions(+)
> 
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index 80647edc2a..3afc6a7b5b 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -758,6 +758,41 @@ void machine_run_board_init(MachineState *machine)
>      if (nb_numa_nodes) {
>          machine_numa_finish_init(machine);
>      }
> +
> +    /* If the machine supports the valid_cpu_types check and the user
> +     * specified a CPU with -cpu check here that the user CPU is supported.
> +     */
> +    if (machine_class->valid_cpu_types && machine->cpu_type) {
> +        ObjectClass *class = object_class_by_name(machine->cpu_type);
> +        int i;
> +
> +        /* machine->cpu_type is supposed to be always a valid QOM type */
> +        assert(class);
> +
> +        for (i = 0; machine_class->valid_cpu_types[i]; i++) {
> +            if (object_class_dynamic_cast(class,
> +                                          machine_class->valid_cpu_types[i])) {
> +                /* The user specificed CPU is in the valid field, we are
> +                 * good to go.
> +                 */
> +                break;
> +            }
> +        }
> +
> +        if (!machine_class->valid_cpu_types[i]) {
> +            /* The user specified CPU must not be a valid CPU */
> +            error_report("Invalid CPU type: %s", machine->cpu_type);
> +            error_printf("The valid types are: %s",
> +                         machine_class->valid_cpu_types[0]);
> +            for (i = 1; machine_class->valid_cpu_types[i]; i++) {
> +                error_printf(", %s", machine_class->valid_cpu_types[i]);
> +            }
> +            error_printf("\n");
> +
> +            exit(1);
> +        }
> +    }
> +
>      machine_class->init(machine);
>  }
>  
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 156e0a5701..191a5b3cd8 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -191,6 +191,7 @@ struct MachineClass {
>      bool has_hotpluggable_cpus;
>      bool ignore_memory_transaction_failures;
>      int numa_mem_align_shift;
> +    const char **valid_cpu_types;
>      void (*numa_auto_assign_ram)(MachineClass *mc, NodeInfo *nodes,
>                                   int nb_nodes, ram_addr_t size);
>  
> -- 
> 2.11.0
> 

-- 
Eduardo