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From: "Verma, Vishal L" <vishal.l.verma@intel.com>
To: "kas@kernel.org" <kas@kernel.org>
Cc: "rdunlap@infradead.org" <rdunlap@infradead.org>,
	"corbet@lwn.net" <corbet@lwn.net>,
	"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	"skhan@linuxfoundation.org" <skhan@linuxfoundation.org>,
	"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [PATCH v3 2/2] x86/early_printk: Add earlyprintk=tdx to drive the UART with TDVMCALLs
Date: Mon, 28 Sep 2026 23:07:52 +0000	[thread overview]
Message-ID: <c41ffc542bd677b71bcecbe4e2c2e2a3b605ffcf.camel@intel.com> (raw)
In-Reply-To: <arZbBqArD9NqWPry@thinkstation>

On Fri, 2026-09-25 at 12:30 +0100, Kiryl Shutsemau wrote:

> 
> All these #ifdefs in early_printk.c can go. X86_FEATURE_TDX_GUEST is a
> disabled feature without CONFIG_INTEL_TDX_GUEST, so
> cpu_feature_enabled() folds to zero and the compiler drops the
> static_call_update() calls and the wrappers with them.
> 
> Add stubs for tdx_inb() and tdx_outb() to the #else branch in
> <asm/tdx.h> and make the "tdx" case unconditional.

Tried this - it causes an objtool error:

     CC      arch/x86/kernel/early_printk.o
   arch/x86/kernel/early_printk.o: error: objtool: bad .discard.annotate_insn entry: 4 of type 1
   make: *** [Makefile:248: __sub-make] Error 2

It can be fixed by adding a __used annotation to the wrappers, but is that
ok?


      reply	other threads:[~2026-09-28 23:08 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-22 20:20 [PATCH v3 0/2] x86/tdx: Use TDVMCALLs directly for earlyprintk Vishal Verma
2026-09-22 20:20 ` [PATCH v3 1/2] x86/tdx: Move port I/O definitions to a shared header Vishal Verma
2026-09-22 20:20 ` [PATCH v3 2/2] x86/early_printk: Add earlyprintk=tdx to drive the UART with TDVMCALLs Vishal Verma
2026-09-25 11:30   ` Kiryl Shutsemau
2026-09-28 23:07     ` Verma, Vishal L [this message]

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