> On 28 Aug 2024, at 4:53 PM, Markus Armbruster <armbru@xxxxxxxxxx> wrote:
>
> Ani Sinha <anisinha@xxxxxxxxxx> writes:
>
>> error_report() is more appropriate for error situations. Replace fprintf with
>> error_report() and error_printf() as appropriate. Cosmetic. No functional
>> change.
>
> Uh, I missed this last time around: the change is more than just
> cosmetics! The error messages change, e.g. from
>
> $ qemu-system-x86_64 -nodefaults -S -display none --accel kvm
> qemu-system-x86_64: --accel kvm: Could not access KVM kernel module: Permission denied
> qemu-system-x86_64: --accel kvm: failed to initialize kvm: Permission denied
>
> to
>
> $ qemu-system-x86_64 -nodefaults -S -display none --accel kvm
> Could not access KVM kernel module: Permission denied
> qemu-system-x86_64: --accel kvm: failed to initialize kvm: Permission denied
You got this backwards. This is what I have:
Before:
$ ./qemu-system-x86_64 --accel kvm
Could not access KVM kernel module: No such file or directory
qemu-system-x86_64: --accel kvm: failed to initialize kvm: No such file or directory
Now:
$ ./qemu-system-x86_64 --accel kvm
qemu-system-x86_64: --accel kvm: Could not access KVM kernel module: No such file or directory
qemu-system-x86_64: --accel kvm: failed to initialize kvm: No such file or directory
>
> Note: the second message is from kvm_init()'s caller. Reporting the
> same error twice is wrong, but not this patch's problem.
>
> Moreover, the patch tweaks an error message at [*].
>
> Suggest something like
>
> Replace fprintf() with error_report() and error_printf() where
> appropriate. Error messages improve, e.g. from
>
> Could not access KVM kernel module: Permission denied
>
> to
>
> qemu-system-x86_64: --accel kvm: Could not access KVM kernel module: Permission denied
Yes this seems correct.
>
>> CC: qemu-trivial@xxxxxxxxxx
>> CC: zhao1.liu@xxxxxxxxx
>> CC: armbru@xxxxxxxxxx
>> Reviewed-by: Zhao Liu <zhao1.liu@xxxxxxxxx>
>> Signed-off-by: Ani Sinha <anisinha@xxxxxxxxxx>
>> ---
>> 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.
>> v4: changes suggested by Markus.
>> v5: more changes from Markus's comments on v4.
>>
>> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
>> index 75d11a07b2..fcc157f0e6 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: %s", strerror(-ret));
>
> [*] This is where you change an error message.
>
>>
>> #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_printf("Host kernel setup problem detected."
>> + " Please verify:\n");
>> + error_printf("- for kernels supporting the"
>> + " switch_amode or user_mode parameters, whether");
>> + error_printf(" user space is running in primary address space\n");
>> + error_printf("- for kernels supporting the vm.allocate_pgste"
>> + " sysctl, whether it is enabled\n");
>> }
>> #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_printf("PPC KVM module is not loaded. Try modprobe kvm_%s.\n",
>> + (type == 2) ? "pr" : "hv");
>> }
>> #endif
>> goto err;
>> @@ -2526,9 +2522,9 @@ static int kvm_init(MachineState *ms)
>> nc->name, nc->num, soft_vcpus_limit);
>>
>> if (nc->num > hard_vcpus_limit) {
>> - fprintf(stderr, "Number of %s cpus requested (%d) exceeds "
>> - "the maximum cpus supported by KVM (%d)\n",
>> - nc->name, nc->num, hard_vcpus_limit);
>> + error_report("Number of %s cpus requested (%d) exceeds "
>> + "the maximum cpus supported by KVM (%d)",
>> + nc->name, nc->num, hard_vcpus_limit);
>> exit(1);
>> }
>> }
>> @@ -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_printf("%s", upgrade_note);
>> goto err;
>> }
>
> With the commit message corrected:
> Reviewed-by: Markus Armbruster <armbru@xxxxxxxxxx>
