linux-kernel - [PATCH] x86/tdx: mark tdh_vp_enter() as _

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Message-ID: <20250526204523.562665-1-pbonzini@redhat.com>
Date: Mon, 26 May 2025 16:45:23 -0400
From: Paolo Bonzini <pbonzini@...hat.com>
To: linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
Cc: kernel test robot <lkp@...el.com>,
	Xiaoyao Li <xiaoyao.li@...el.com>
Subject: [PATCH] x86/tdx: mark tdh_vp_enter() as __flatten

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@...el.com>
Analyzed-by: Xiaoyao Li <xiaoyao.li@...el.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202505240530.5KktQ5mX-lkp@intel.com/
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 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);
 
-- 
2.43.5