Re: [PATCH] exit if we fail to initialize kvm

[Jan Kiszka <jan.kiszka@siemens.com>]

Alexander Graf wrote:
> 
> On 28.07.2009, at 23:28, Glauber Costa wrote:
> 
>> On Tue, Jul 28, 2009 at 11:15:19PM +0200, Alexander Graf wrote:
>>>
>>> On 28.07.2009, at 22:52, Glauber Costa <glommer@redhat.com> wrote:
>>>
>>>> Falling back to tcg has proven to be evil through time. The option is
>>>> to
>>>> do not try to act behind user's back, and quit the program completely
>>>> if
>>>> we fail to initialize kvm. Right now, the only way to run tcg from our
>>>> tree
>>>> becomes explicitly asking for it, with the -no-kvm option.
>>>
>>> Well, actually there's one little difference: I tell the user to use -
>>> no-kvm if he really wants cpu emulation.
>>>
>>> But simply failing is probably good enough.
>> With my patch, we won't fail if the user asked -no-kvm, because then
>> we won't
>> even try to initialize kvm.
>>
>> We only exit here, if we try, but fail
> 
> This is the patch as I had it in kvm-86. It's really only about being
> helpful to the user.
> 
> Index: kvm-86/vl.c
> ===================================================================
> --- kvm-86.orig/vl.c
> +++ kvm-86/vl.c
> @@ -5836,7 +5836,8 @@ int main(int argc, char **argv, char **e
>  #ifdef USE_KVM
>      if (kvm_enabled()) {
>      if (kvm_qemu_init() < 0) {
> -        fprintf(stderr, "Could not initialize KVM, will disable KVM
> support\n");
> +        fprintf(stderr, "Could not initialize KVM. Do you have kvm-amd
> or kvm-intel modprobe'd?\nIf you want to use CPU emulation, start with
> -no-kvm.\n");
> +        exit(1);
>  #ifdef NO_CPU_EMULATION
>          fprintf(stderr, "Compiled with --disable-cpu-emulation,
> exiting.\n");
>          exit(1);

Yes, that's a useful hint which should be included.

I just wonder now if/when qemu-kvm will switch over to the
kvm-by-default-off policy of upstream?

Jan

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