> +static void kvm_uninit_virtualization(void)
> +{
> + if (enable_virt_at_load)
> + kvm_disable_virtualization();
> +
> + WARN_ON(kvm_usage_count);
> +}
>
Hi Sean,
The above "WARN_ON(kvm_usage_count);" assumes the
kvm_uninit_virtualization() is the last call of
kvm_disable_virtualization(), and it is called ...
> @@ -6433,6 +6468,8 @@ void kvm_exit(void)
> */
> misc_deregister(&kvm_dev);
>
> + kvm_uninit_virtualization();
> +
>
... from kvm_exit().
Accordingly, kvm_init_virtualization() is called in kvm_init().
For TDX, we want to "explicitly call kvm_enable_virtualization() +
initializing TDX module" before kvm_init() in vt_init(), since kvm_init()
is supposed to be the last step after initializing TDX.
In the exit path, accordingly, for TDX we want to call kvm_exit() first,
and then "do TDX cleanup staff + explicitly call
kvm_disable_virtualizaation()".
This will trigger the above "WARN_ON(kvm_usage_count);" when
enable_virt_at_load is true, because kvm_uninit_virtualization() isn't
the last call of kvm_disable_virtualization().
To resolve, I think one way is we can move kvm_init_virtualization() out
of kvm_init(), but I am not sure whether there's another common place
that kvm_init_virtualization() can be called for all ARCHs.
Do you have any comments?
