On Mon, May 26, 2025, Paolo Bonzini wrote:
> In some cases tdx_tdvpr_pa() is not fully inlined into tdh_vp_enter(), which
> causes the following warning:
>
> vmlinux.o: warning: objtool: tdh_vp_enter+0x8: call to tdx_tdvpr_pa() leaves .noinstr.text section
>
> This happens if the compiler considers tdx_tdvpr_pa() to be "large", for example
> because CONFIG_SPARSEMEM adds two function calls to page_to_section() and
> __section_mem_map_addr():
>
> ({ const struct page *__pg = (pg); \
> int __sec = page_to_section(__pg); \
> (unsigned long)(__pg - __section_mem_map_addr(__nr_to_section(__sec)));
> \
> })
>
> Because exiting the noinstr section is a no-no, just mark tdh_vp_enter() for
> full inlining.
>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Analyzed-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202505240530.5KktQ5mX-lkp@xxxxxxxxx/
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> arch/x86/virt/vmx/tdx/tdx.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
> index f5e2a937c1e7..2457d13c3f9e 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.c
> +++ b/arch/x86/virt/vmx/tdx/tdx.c
> @@ -1517,7 +1517,7 @@ static void tdx_clflush_page(struct page *page)
> clflush_cache_range(page_to_virt(page), PAGE_SIZE);
> }
>
> -noinstr u64 tdh_vp_enter(struct tdx_vp *td, struct tdx_module_args *args)
> +noinstr __flatten u64 tdh_vp_enter(struct tdx_vp *td, struct tdx_module_args *args)
> {
> args->rcx = tdx_tdvpr_pa(td);
The "standard" kernel way of handling this it to mark the offending helper
__always_inline, i.e. tag tdx_tdvpr_pa() __always_inline. Ditto for tdx_tdr_pa().
Especially since they're already "inline".
