[PATCH for-7.1?] kvm: don't use perror() without useful errno

[PATCH for-7.1?] kvm: don't use perror() without useful errno

[Cornelia Huck]

perror() is designed to append the decoded errno value to a
string. This, however, only makes sense if we called something that
actually sets errno prior to that.

For the callers that check for split irqchip support that is not the
case, and we end up with confusing error messages that end in
"success". Use error_report() instead.

Signed-off-by: Cornelia Huck <cohuck@redhat.com>
---

Not sure if that is still 7.1 material; on the one hand, it's a small
fix; on the other hand, it has been like that forever...

I've kept the Arm-specific message in place, although it might be redundant.

---
 accel/kvm/kvm-all.c | 2 +-
 target/arm/kvm.c    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 99aede73b7cb..6955c0b23a22 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -2265,7 +2265,7 @@ static void kvm_irqchip_create(KVMState *s)
     ret = kvm_arch_irqchip_create(s);
     if (ret == 0) {
         if (s->kernel_irqchip_split == ON_OFF_AUTO_ON) {
-            perror("Split IRQ chip mode not supported.");
+            error_report("Split IRQ chip mode not supported.");
             exit(1);
         } else {
             ret = kvm_vm_ioctl(s, KVM_CREATE_IRQCHIP);
diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index 4339e1cd6e08..e5c1bd50d29b 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -959,7 +959,7 @@ void kvm_arch_init_irq_routing(KVMState *s)
 int kvm_arch_irqchip_create(KVMState *s)
 {
     if (kvm_kernel_irqchip_split()) {
-        perror("-machine kernel_irqchip=split is not supported on ARM.");
+        error_report("-machine kernel_irqchip=split is not supported on ARM.");
         exit(1);
     }
 
-- 
2.35.3

Re: [PATCH for-7.1?] kvm: don't use perror() without useful errno

[Richard Henderson]

On 7/28/22 07:24, Cornelia Huck wrote:
> perror() is designed to append the decoded errno value to a
> string. This, however, only makes sense if we called something that
> actually sets errno prior to that.
> 
> For the callers that check for split irqchip support that is not the
> case, and we end up with confusing error messages that end in
> "success". Use error_report() instead.
> 
> Signed-off-by: Cornelia Huck<cohuck@redhat.com>
> ---

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~

Re: [PATCH for-7.1?] kvm: don't use perror() without useful errno

[Paolo Bonzini]

Queued, thanks.

Paolo