Re: [PATCH v2 04/16] KVM: VMX: Introduce unified instruction info structure

[Chang S. Bae]

On 3/4/2026 8:21 PM, Sean Christopherson wrote:
> Absolutely not.  I despise bit fields, as they're extremely difficult to review,
> don't help developers/debuggers understand the expected layout (finding flags and
> whatnot in .h files is almost always faster than searching the SDM), and they
> often generate suboptimal code.

Okay.

> I don't see any reason to do anything more complicated than:
>
> static inline u64 vmx_get_insn_info(void)
> {
> 	if (vmx_insn_info_extended())
> 		return vmcs_read64(EXTENDED_INSTRUCTION_INFO);
>
> 	return vmcs_read32(VMX_INSTRUCTION_INFO);
> }
>
> static inline int vmx_get_insn_info_reg(u64 insn_info)
> {
> 	return vmx_insn_info_extended() ? (insn_info >> ??) & 0x1f :
> 					  (insn_info >> 3) & 0xf;
> }

There is

int get_vmx_mem_address(...)
{
	...

	/*
	 * According to Vol. 3B,...
	 */
	int  scaling = vmx_instruction_info & 3;
	int  addr_size = (vmx_instruction_info >> 7) & 7;
	bool is_reg = vmx_instruction_info & (1u << 10);
	int  seg_reg = (vmx_instruction_info >> 15) & 7;
	int  index_reg = (vmx_instruction_info >> 18) & 0xf;
	bool index_is_valid = !(vmx_instruction_info & (1u << 22));
	int  base_reg       = (vmx_instruction_info >> 23) & 0xf;
	bool base_is_valid  = !(vmx_instruction_info & (1u << 27));

I'd assume wrappers like above for each line there. But to confirm your 
preference: would you rather keep this open-coded, or introduce another 
wrappers for each?