Update the CPUID handling in kernel

[vibhutet]

The kernel forwards most CPUID intercepts received in #VE handler to the user mode without any particular handling. Ex. For CPUID leaf 0xB the user mode receives all 0s. This CPUID is used to identify the topology of the CVM. Receiving all 0s leads to incorrect building and identification of topology.
Fix the CPUID intercept in the kernel. Once that is fixed, on the user mode review the validation of leaf 0xB in extended_topology()

[chris-oo]

What exactly is the issue here - that we cannot get the right information we need in usermode via cpuid because the kernel is not filling out the right info in the #VE handler? Does the kernel even know that info or do we need to also update the kernel to query the correct TDX module, or what is the ultimate source of this information?

[vibhutet]

The kernel needs to query the TDX module to get the right information and pass it to the user mode.