Jan Kiszka <[email protected]> wrote:
> From: Jan Kiszka <[email protected]>
>
> To be used for in-kernel PIT emulation.
....
> + int pit_state2;
This is used as a bool.
> int xsave, xcrs;
> int many_ioeventfds;
> int irqchip_inject_ioctl;
> @@ -954,6 +955,10 @@ int kvm_init(void)
> s->xcrs = kvm_check_extension(s, KVM_CAP_XCRS);
> #endif
>
> +#ifdef KVM_CAP_PIT_STATE2
> + s->pit_state2 = kvm_check_extension(s, KVM_CAP_PIT_STATE2);
> +#endif
> +
[ this happened to me when I was reviewing this patch, but culprit is
not this patch]
really kvm_check_extension() should also return a bool, but that is a
bigger change that this patch series tend to introduce.
So, I went to "man ioctl"
> RETURN VALUE
> Usually, on success zero is returned. A few ioctl() requests use the
> return value as an output parameter and return a nonnegative value on
> success. On error, -1 is returned, and errno is set appropriately.
Usually is the important word there.
And then went to kvm-all.c
int kvm_check_extension(KVMState *s, unsigned int extension)
{
int ret;
ret = kvm_ioctl(s, KVM_CHECK_EXTENSION, extension);
if (ret < 0) {
ret = 0;
}
return ret;
}
What? it allways return zero? Something should be wrong here. I will
expect kvm_check_extension() to work by now.
Yes, kvm_ioctl() return 1 went the extension is there, just for the
people confused like me.
Later, Juan.
