hw/arm/virt: Improve CPU help and fix testing under KVM

[PATCH 6/9] hw/arm/virt: Display list of valid CPUs for the Virt machine

Posted by Philippe Mathieu-Daudé 5 years ago

The Virt machine is restricted to a subset of the CPU provided
by QEMU. Instead of having the user run '--cpu help' and try
each CPUs until finding a match, display the list from start:

  $ qemu-system-aarch64 -M virt -cpu cortex-a8
  qemu-system-aarch64: mach-virt: CPU type cortex-a8 not supported
  qemu-system-aarch64: mach-virt: Please select one of the following CPU types:  cortex-a7, cortex-a15, cortex-a53, cortex-a57, cortex-a72, host, max

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/arm/virt.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 7802d3a66e8..6ffe091804f 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1830,9 +1830,20 @@ static void machvirt_init(MachineState *machine)
 
     if (!cpu_type_valid(machine->cpu_type)) {
         int len = strlen(machine->cpu_type) - strlen(ARM_CPU_TYPE_SUFFIX);
+        g_autoptr(GString) s = g_string_new(NULL);
 
         error_report("mach-virt: CPU type %.*s not supported",
                      len, machine->cpu_type);
+
+        for (n = 0; n < ARRAY_SIZE(valid_cpus); n++) {
+            len = strlen(valid_cpus[n]) - strlen(ARM_CPU_TYPE_SUFFIX);
+            g_string_append_printf(s, " %.*s", len, valid_cpus[n]);
+            if (n + 1 < ARRAY_SIZE(valid_cpus)) {
+                g_string_append_c(s, ',');
+            }
+        }
+        error_report("mach-virt: Please select one of the following CPU types: %s",
+                     g_string_free(s, FALSE));
         exit(1);
     }
 
-- 
2.26.2

Re: [PATCH 6/9] hw/arm/virt: Display list of valid CPUs for the Virt machine

Posted by Andrew Jones 5 years ago

On Fri, Feb 05, 2021 at 03:43:42PM +0100, Philippe Mathieu-Daudé wrote:
> The Virt machine is restricted to a subset of the CPU provided
> by QEMU. Instead of having the user run '--cpu help' and try
> each CPUs until finding a match, display the list from start:
> 
>   $ qemu-system-aarch64 -M virt -cpu cortex-a8
>   qemu-system-aarch64: mach-virt: CPU type cortex-a8 not supported
>   qemu-system-aarch64: mach-virt: Please select one of the following CPU types:  cortex-a7, cortex-a15, cortex-a53, cortex-a57, cortex-a72, host, max
> 
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  hw/arm/virt.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 7802d3a66e8..6ffe091804f 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -1830,9 +1830,20 @@ static void machvirt_init(MachineState *machine)
>  
>      if (!cpu_type_valid(machine->cpu_type)) {
>          int len = strlen(machine->cpu_type) - strlen(ARM_CPU_TYPE_SUFFIX);
> +        g_autoptr(GString) s = g_string_new(NULL);
>  
>          error_report("mach-virt: CPU type %.*s not supported",
>                       len, machine->cpu_type);
> +
> +        for (n = 0; n < ARRAY_SIZE(valid_cpus); n++) {
> +            len = strlen(valid_cpus[n]) - strlen(ARM_CPU_TYPE_SUFFIX);
> +            g_string_append_printf(s, " %.*s", len, valid_cpus[n]);
> +            if (n + 1 < ARRAY_SIZE(valid_cpus)) {
> +                g_string_append_c(s, ',');
> +            }
> +        }
> +        error_report("mach-virt: Please select one of the following CPU types: %s",
> +                     g_string_free(s, FALSE));
>          exit(1);
>      }
>  
> -- 
> 2.26.2
>

It'd be nice if './qemu-system-aarch64 -M virt -cpu \?' would only output
the CPUs that the virt machine type supports. Then this error message
could suggest running that in order to get the list.

Thanks,
drew

Re: [PATCH 6/9] hw/arm/virt: Display list of valid CPUs for the Virt machine

Posted by Philippe Mathieu-Daudé 5 years ago

On 2/5/21 4:12 PM, Andrew Jones wrote:
> On Fri, Feb 05, 2021 at 03:43:42PM +0100, Philippe Mathieu-Daudé wrote:
>> The Virt machine is restricted to a subset of the CPU provided
>> by QEMU. Instead of having the user run '--cpu help' and try
>> each CPUs until finding a match, display the list from start:
>>
>>   $ qemu-system-aarch64 -M virt -cpu cortex-a8
>>   qemu-system-aarch64: mach-virt: CPU type cortex-a8 not supported
>>   qemu-system-aarch64: mach-virt: Please select one of the following CPU types:  cortex-a7, cortex-a15, cortex-a53, cortex-a57, cortex-a72, host, max
>>
>> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>> ---
>>  hw/arm/virt.c | 11 +++++++++++
>>  1 file changed, 11 insertions(+)
>>
>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>> index 7802d3a66e8..6ffe091804f 100644
>> --- a/hw/arm/virt.c
>> +++ b/hw/arm/virt.c
>> @@ -1830,9 +1830,20 @@ static void machvirt_init(MachineState *machine)
>>  
>>      if (!cpu_type_valid(machine->cpu_type)) {
>>          int len = strlen(machine->cpu_type) - strlen(ARM_CPU_TYPE_SUFFIX);
>> +        g_autoptr(GString) s = g_string_new(NULL);
>>  
>>          error_report("mach-virt: CPU type %.*s not supported",
>>                       len, machine->cpu_type);
>> +
>> +        for (n = 0; n < ARRAY_SIZE(valid_cpus); n++) {
>> +            len = strlen(valid_cpus[n]) - strlen(ARM_CPU_TYPE_SUFFIX);
>> +            g_string_append_printf(s, " %.*s", len, valid_cpus[n]);
>> +            if (n + 1 < ARRAY_SIZE(valid_cpus)) {
>> +                g_string_append_c(s, ',');
>> +            }
>> +        }
>> +        error_report("mach-virt: Please select one of the following CPU types: %s",
>> +                     g_string_free(s, FALSE));
>>          exit(1);
>>      }
>>  
>> -- 
>> 2.26.2
>>
> 
> It'd be nice if './qemu-system-aarch64 -M virt -cpu \?' would only output
> the CPUs that the virt machine type supports. Then this error message
> could suggest running that in order to get the list.

+1 very nice =) But not how the command line options processing
works. Maybe later after John Snow command line rework is merged?