Re: [PATCH v8 09/11] x86/tdx: Add MSR support for TDX guest

[Josh Poimboeuf]

On Mon, Oct 04, 2021 at 07:52:03PM -0700, Kuppuswamy Sathyanarayanan wrote:
> From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
> 
> Use hypercall to emulate MSR read/write for TDX platform.
> 
> TDVMCALL[Instruction.RDMSR] and TDVMCALL[Instruction.WRMSR] provide MSR
> oprations.
> 
> RDMSR and WRMSR specification details can be found in
> Guest-Host-Communication Interface (GHCI) for Intel Trust Domain
> Extensions (Intel TDX) specification, sec titled "TDG.VP.
> VMCALL<Instruction.RDMSR>" and "TDG.VP.VMCALL<Instruction.WRMSR>".
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> Reviewed-by: Tony Luck <tony.luck@xxxxxxxxx>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> ---
> 
> Changes since v7:
>  * Removed tdx_is_context_switched_msr() support (since the list
>    is incomplete).

This fails to build:

arch/x86/kernel/tdx.c: In function ‘tdx_write_msr_safe’:
arch/x86/kernel/tdx.c:135:22: error: implicit declaration of function ‘tdx_is_context_switched_msr’ [-Werror=implicit-function-declaration]
  135 |         WARN_ON_ONCE(tdx_is_context_switched_msr(msr));
      |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/asm-generic/bug.h:104:32: note: in definition of macro ‘WARN_ON_ONCE’
  104 |         int __ret_warn_on = !!(condition);                      \
      |                                ^~~~~~~~~

-- 
Josh