kvm: kvm_init_vcpu take Error pointer

Clean up the error handling in kvm_init_vcpu so we can see what went
wrong more easily.

Make it take an Error ** and fill it out with what failed, including
the cpu id, so you can tell if it only fails at a given ID.

Replace the remaining DPRINTF by a trace.

This turns a:
kvm_init_vcpu failed: Invalid argument

into:
kvm_init_vcpu: kvm_get_vcpu failed (256): Invalid argument

and with the trace you then get to see:

19049@1595520414.310107:kvm_init_vcpu index: 169 id: 212
19050@1595520414.310635:kvm_init_vcpu index: 170 id: 256
qemu-system-x86_64: kvm_init_vcpu: kvm_get_vcpu failed (256): Invalid argument

which makes stuff a lot more obvious.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200723160915.129069-1-dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 14 insertions, 5 deletions

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 784e9dad55..9ef5daf4c5 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -441,17 +441,18 @@ static int kvm_get_vcpu(KVMState *s, unsigned long vcpu_id)
     return kvm_vm_ioctl(s, KVM_CREATE_VCPU, (void *)vcpu_id);
 }
 
-int kvm_init_vcpu(CPUState *cpu)
+int kvm_init_vcpu(CPUState *cpu, Error **errp)
 {
     KVMState *s = kvm_state;
     long mmap_size;
     int ret;
 
-    DPRINTF("kvm_init_vcpu\n");
+    trace_kvm_init_vcpu(cpu->cpu_index, kvm_arch_vcpu_id(cpu));
 
     ret = kvm_get_vcpu(s, kvm_arch_vcpu_id(cpu));
     if (ret < 0) {
-        DPRINTF("kvm_create_vcpu failed\n");
+        error_setg_errno(errp, -ret, "kvm_init_vcpu: kvm_get_vcpu failed (%lu)",
+                         kvm_arch_vcpu_id(cpu));
         goto err;
     }
 
@@ -462,7 +463,8 @@ int kvm_init_vcpu(CPUState *cpu)
     mmap_size = kvm_ioctl(s, KVM_GET_VCPU_MMAP_SIZE, 0);
     if (mmap_size < 0) {
         ret = mmap_size;
-        DPRINTF("KVM_GET_VCPU_MMAP_SIZE failed\n");
+        error_setg_errno(errp, -mmap_size,
+                         "kvm_init_vcpu: KVM_GET_VCPU_MMAP_SIZE failed");
         goto err;
     }
 
@@ -470,7 +472,9 @@ int kvm_init_vcpu(CPUState *cpu)
                         cpu->kvm_fd, 0);
     if (cpu->kvm_run == MAP_FAILED) {
         ret = -errno;
-        DPRINTF("mmap'ing vcpu state failed\n");
+        error_setg_errno(errp, ret,
+                         "kvm_init_vcpu: mmap'ing vcpu state failed (%lu)",
+                         kvm_arch_vcpu_id(cpu));
         goto err;
     }
 
@@ -480,6 +484,11 @@ int kvm_init_vcpu(CPUState *cpu)
     }
 
     ret = kvm_arch_init_vcpu(cpu);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret,
+                         "kvm_init_vcpu: kvm_arch_init_vcpu failed (%lu)",
+                         kvm_arch_vcpu_id(cpu));
+    }
 err:
     return ret;
 }