Re: [PATCH v2 1/2] kvm: replace fprintf with error_report() in kvm_init() for error conditions

[Zhao Liu <zhao1.liu@intel.com>]

On Fri, Aug 09, 2024 at 10:40:53AM +0530, Ani Sinha wrote:
> Date: Fri,  9 Aug 2024 10:40:53 +0530
> From: Ani Sinha <anisinha@redhat.com>
> Subject: [PATCH v2 1/2] kvm: replace fprintf with error_report() in
>  kvm_init() for error conditions
> X-Mailer: git-send-email 2.45.2
> 
> 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
> 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.

Generally good to me. Only some nits below, otherwise,

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>

>  #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. Please verify:");

The doc of error_report() said it doesn't want multiple sentences or trailing
punctuation:

"The resulting message should be a single phrase, with no newline or trailing
punctuation."

So I think these extra messages (with complex formatting & content) are
better printed with error_printf() as I suggested in [1].

[1]: https://lore.kernel.org/qemu-devel/ZrWP0fWPNzeAvjja@intel.com/T/#m953afd879eb6279fcdf03cda594c43f1829bdffe

> +            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");
>          }
>  #elif defined(TARGET_PPC)
>          if (ret == -EINVAL) {
> -            fprintf(stderr,
> -                    "PPC KVM module is not loaded. Try modprobe kvm_%s.\n",
> -                    (type == 2) ? "pr" : "hv");
> +            error_report("PPC KVM module is not loaded. Try modprobe kvm_%s.",
> +                        (type == 2) ? "pr" : "hv");

Same here. A trailing punctuation. If possible, feel free to refer to
the comment in [1].

>          }
>  #endif

[snip]

> @@ -2542,8 +2538,8 @@ static int kvm_init(MachineState *ms)
>      }
>      if (missing_cap) {
>          ret = -EINVAL;
> -        fprintf(stderr, "kvm does not support %s\n%s",
> -                missing_cap->name, upgrade_note);
> +        error_report("kvm does not support %s", missing_cap->name);
> +        error_report("%s", upgrade_note);

"upgrade_note" string also has the trailing punctuation, and it's
also better to use error_printf() to replace the 2nd error_report().

For this patch, error_report() is already a big step forward, so I think
these few nits doesn't block this patch.

Thank you for your patience.
Zhao