From: Nikolay Borisov <redacted>
[...]

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Actually now shouldn't the CONFIG_PARAVIRT_SPINLOCKS check be

retained?

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Otherwise we'll have the virtspinlock enabled even if we are a guest
but CONFIG_PARAVIRT_SPINLOCKS is disabled, no ?

It seems to be the expected behavior? If CONFIG_PARAVIRT_SPINLOCKS is
disabled, should the virt_spin_lock_key be enabled in the guest?

No, but if it's disabled and we are under a hypervisor shouldn't the virt
spinlock be kept disabled? 

No, the virt_spin_lock_key shouldn't be kept disabled.

According to the comments [1], in the hypervisor if CONFIG_PARAVIRT_SPINLOCKS
is disabled,  the virt_spin_lock_key should be enabled to fall back to the TAS spinlock.

[1] https://github.com/torvalds/linux/blob/master/arch/x86/include/asm/qspinlock.h#L94

According to the comments [2]:
So my understanding is that in hypervisor keeping virt_spin_lock_key enabled allows
the spinlock fallback to TAS if PV spinlock is not supported (either CONFIG_PARAVIRT_SPINLOCKS=n
or the host doesn't support the PV feature)

[2] https://github.com/torvalds/linux/blob/master/arch/x86/kernel/kvm.c#L1073

As it stands now everytime we are under a
hypervisor the virt spinlock is enabled irrespective of the PARAVIRT_SPINLOCK
config state.

According to [1] [2], yes, I think so, 

-Qiuxu