Re: [PATCH v3] kvm: replace fprintf with error_report/printf() in kvm_init()

[Markus Armbruster <armbru@redhat.com>]

Philippe Mathieu-Daudé <philmd@linaro.org> writes:

> Hi Ani,
>
> On 9/8/24 08:49, Ani Sinha wrote:
>> error_report() is more appropriate for error situations. Replace fprintf with
>> error_report. Cosmetic. No functional change.
>> CC: qemu-trivial@nongnu.org
>> CC: zhao1.liu@intel.com
>
> (Pointless to carry Cc line when patch is already reviewed next line)
>
>> Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
>> Signed-off-by: Ani Sinha <anisinha@redhat.com>
>> ---
>>   accel/kvm/kvm-all.c | 40 ++++++++++++++++++----------------------
>>   1 file changed, 18 insertions(+), 22 deletions(-)
>> changelog:
>> v2: fix a bug.
>> v3: replace one instance of error_report() with error_printf(). added tags.
>> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
>> index 75d11a07b2..5bc9d35b61 100644
>> --- a/accel/kvm/kvm-all.c
>> +++ b/accel/kvm/kvm-all.c
>> @@ -2427,7 +2427,7 @@ static int kvm_init(MachineState *ms)
>>       QLIST_INIT(&s->kvm_parked_vcpus);
>>       s->fd = qemu_open_old(s->device ?: "/dev/kvm", O_RDWR);
>>       if (s->fd == -1) {
>> -        fprintf(stderr, "Could not access KVM kernel module: %m\n");
>> +        error_report("Could not access KVM kernel module: %m");
>>           ret = -errno;
>>           goto err;
>>       }
>> @@ -2437,13 +2437,13 @@ static int kvm_init(MachineState *ms)
>>           if (ret >= 0) {
>>               ret = -EINVAL;
>>           }
>> -        fprintf(stderr, "kvm version too old\n");
>> +        error_report("kvm version too old");
>>           goto err;
>>       }
>>         if (ret > KVM_API_VERSION) {
>>           ret = -EINVAL;
>> -        fprintf(stderr, "kvm version not supported\n");
>> +        error_report("kvm version not supported");
>>           goto err;
>>       }
>>   @@ -2488,26 +2488,22 @@ static int kvm_init(MachineState *ms)
>>       } while (ret == -EINTR);
>>         if (ret < 0) {
>> -        fprintf(stderr, "ioctl(KVM_CREATE_VM) failed: %d %s\n", -ret,
>> -                strerror(-ret));
>> +        error_report("ioctl(KVM_CREATE_VM) failed: %d %s", -ret,
>> +                    strerror(-ret));
>>     #ifdef TARGET_S390X
>>           if (ret == -EINVAL) {
>> -            fprintf(stderr,
>> -                    "Host kernel setup problem detected. Please verify:\n");
>> -            fprintf(stderr, "- for kernels supporting the switch_amode or"
>> -                    " user_mode parameters, whether\n");
>> -            fprintf(stderr,
>> -                    "  user space is running in primary address space\n");
>> -            fprintf(stderr,
>> -                    "- for kernels supporting the vm.allocate_pgste sysctl, "
>> -                    "whether it is enabled\n");
>> +            error_report("Host kernel setup problem detected.
>
> \n"
>
> Should we use error_printf_unless_qmp() for the following?
>
> " Please verify:");
>> +            error_report("- for kernels supporting the switch_amode or"
>> +                        " user_mode parameters, whether");
>> +            error_report("  user space is running in primary address space");
>> +            error_report("- for kernels supporting the vm.allocate_pgste "
>> +                        "sysctl, whether it is enabled");

Do not put newlines into error messages.  error_report()'s function
comment demands "The resulting message should be a single phrase, with
no newline or trailing punctuation."

You can do this:

    error_report(... the actual error message ...);
    error_printf(... hints on what to do about it ...);

Questions?

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