Re: [RFC] Expose L1 guest register state for nested VMX via KVM_GET_NESTED_STATE

Thanks for the thorough review.

You're right -- vmcs12.HOST_xxx already carries the essential L1 context
(HOST_RSP, HOST_RIP, HOST_CR3, HOST_CR4, HOST_EFER, segment selectors
and bases), and KVM_GET_NESTED_STATE already returns this data to
userspace.  I was focused on vmcs01 GUEST fields and overlooked that the
HOST area provides a practical equivalent for debugging purposes.

I'll drop the kernel UAPI extension and instead work on a userspace-only
solution that parses the existing vmcs12 HOST fields to present L1 state
in QEMU's monitor.

Thanks,
Zhengrong Li