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

[Markus Armbruster]

Ani Sinha <anisinha@redhat.com> writes:

>> On 27 Aug 2024, at 12:00 PM, Markus Armbruster <armbru@redhat.com> wrote:
>> 
>> 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?
>
> Do you see any newlines in my proposed patch?

I see some in Philippe's suggestion.

Your patch's use of multiple error_report() for a single error condition
is inappropriate.

Questions?