apic: Make APIC ID limit error message clearer

Remove the "apic initialization failed" prefix (it conveys no useful information), replace "invalid" with "too large", and add an error hint with two possible solutions for the problem.

Before:

   $ qemu-system-x86_64 -machine q35 -smp 256
   qemu-system-x86_64: apic initialization failed. APIC ID 255 is invalid

After:

   $ qemu-system-x86_64 -machine q35 -smp 256 -display none
   qemu-system-x86_64: APIC ID 255 is too large

Possible solutions:
* Lowering the number of VCPUs on the -smp option
* Using accel=kvm,kernel-irqchip=on or accel=kvm,kernel-irqchip=split

Signed-off-by Eduardo Habkost <[email protected]>

---
I'm not sure this is the best way to provide usage hints to the user. Any suggestions?

---
  hw/intc/apic.c | 7 +++++--
  1 file changed, 5 insertions(+), 2 deletions(-)

hw/intc/apic.c +5 -2

index 97ffdd820f..f08006334d 100644
@@ -886,8 +886,11 @@ static void apic_realize(DeviceState *dev, Error **errp)
      APICCommonState *s = APIC(dev);
 
      if (s->id >= MAX_APICS) {
-        error_setg(errp, "%s initialization failed. APIC ID %d is invalid",
-                   object_get_typename(OBJECT(dev)), s->id);
+        error_setg(errp, "APIC ID %d is too large", s->id);
+        error_append_hint(errp,
+            "Possible solutions:\n"
+            "* Lowering the number of VCPUs on the -smp option\n"
+            "* Using accel=kvm,kernel-irqchip=on or accel=kvm,kernel-irqchip=split\n");
          return;
      }
 

Quoted 9 lines · Eduardo Habkost

Remove the "apic initialization failed" prefix (it conveys no useful information), replace "invalid" with "too large", and add an error hint with two possible solutions for the problem.

Before:

   $ qemu-system-x86_64 -machine q35 -smp 256
   qemu-system-x86_64: apic initialization failed. APIC ID 255 is invalid

Quoted 4 lines

After:

   $ qemu-system-x86_64 -machine q35 -smp 256 -display none
   qemu-system-x86_64: APIC ID 255 is too large

I would keep the problem "apic initialization failed" sentence. "APIC ID 255 is too large" is just the cause.

Quoted 9 lines

Possible solutions:
* Lowering the number of VCPUs on the -smp option
* Using accel=kvm,kernel-irqchip=on or accel=kvm,kernel-irqchip=split

Signed-off-by Eduardo Habkost <[email protected]>

---
I'm not sure this is the best way to provide usage hints to the user. Any suggestions?

As a noob, I can testify that this kind of suggestion is very useful although there seems to not have many on QEMU. On the other hand, I understand it can make qemu verbose and so annoy people. Thus, maybe those suggestions could be enabled/disabled via options (e.g. -show-hints)?

- Wainer

Quoted 20 lines

---
  hw/intc/apic.c | 7 +++++--
  1 file changed, 5 insertions(+), 2 deletions(-)

hw/intc/apic.c +5 -2

index 97ffdd820f..f08006334d 100644
@@ -886,8 +886,11 @@ static void apic_realize(DeviceState *dev, Error **errp)
      APICCommonState *s = APIC(dev);
      if (s->id >= MAX_APICS) {
-        error_setg(errp, "%s initialization failed. APIC ID %d is invalid",
-                   object_get_typename(OBJECT(dev)), s->id);
+        error_setg(errp, "APIC ID %d is too large", s->id);
+        error_append_hint(errp,
+            "Possible solutions:\n"
+            "* Lowering the number of VCPUs on the -smp option\n"
+            "* Using accel=kvm,kernel-irqchip=on or accel=kvm,kernel-irqchip=split\n");
          return;
      }

Quoted 13 lines · Wainer dos Santos Moschetta

Quoted 11 lines · Eduardo Habkost

Remove the "apic initialization failed" prefix (it conveys no useful information), replace "invalid" with "too large", and add an error hint with two possible solutions for the problem.

Before:

   $ qemu-system-x86_64 -machine q35 -smp 256
   qemu-system-x86_64: apic initialization failed. APIC ID 255 is invalid

After:

Quoted 5 lines

Quoted 2 lines

   $ qemu-system-x86_64 -machine q35 -smp 256 -display none
   qemu-system-x86_64: APIC ID 255 is too large

I would keep the problem "apic initialization failed" sentence. "APIC ID 255 is too large" is just the cause.

I'm not sure I agree. "APIC initialization failed" doesn't convey any useful information to the user, does it?

Quoted 9 lines

Quoted 8 lines

Possible solutions:
* Lowering the number of VCPUs on the -smp option
* Using accel=kvm,kernel-irqchip=on or accel=kvm,kernel-irqchip=split

Signed-off-by Eduardo Habkost <[email protected]>

---
I'm not sure this is the best way to provide usage hints to the user. Any suggestions?

Quoted 4 lines

As a noob, I can testify that this kind of suggestion is very useful although there seems to not have many on QEMU. On the other hand, I understand it can make qemu verbose and so annoy people. Thus, maybe those suggestions could be enabled/disabled via options (e.g. -show-hints)?

I can't imagine who would be annoyed by them.