Re: [PATCH v2 19/31] iommu/vt-d: Reserve the MSB domain ID bit for the TDX module

[Xu Yilun <yilun.xu@linux.intel.com>]

On Tue, Mar 31, 2026 at 03:20:44PM +0800, Baolu Lu wrote:
> On 3/29/26 00:57, kernel test robot wrote:
> > kernel test robot noticed the following build warnings:
> > 
> > [auto build test WARNING on 11439c4635edd669ae435eec308f4ab8a0804808]
> > 
> > url:https://github.com/intel-lab-lkp/linux/commits/Xu-Yilun/x86-tdx-Move-
> > all-TDX-error-defines-into-asm-shared-tdx_errno-h/20260328-151524
> > base:   11439c4635edd669ae435eec308f4ab8a0804808
> > patch link:https://lore.kernel.org/r/20260327160132.2946114-20-
> > yilun.xu%40linux.intel.com
> > patch subject: [PATCH v2 19/31] iommu/vt-d: Reserve the MSB domain ID bit for the TDX module
> > config: i386-randconfig-141-20260328
> > (https://download.01.org/0day-ci/archive/20260329/202603290006.za7iiDgF-
> > lkp@intel.com/config)
> > compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
> > smatch: v0.5.0-9004-gb810ac53
> > reproduce (this is a W=1 build):
> > (https://download.01.org/0day-ci/archive/20260329/202603290006.za7iiDgF-
> > lkp@intel.com/reproduce)
> > 
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot<lkp@intel.com>
> > | Closes:https://lore.kernel.org/oe-kbuild-all/202603290006.za7iiDgF-lkp@intel.com/
> > 
> > All warnings (new ones prefixed by >>, old ones prefixed by <<):
> > 
> > > > WARNING: modpost: vmlinux: section mismatch in reference: iommu_max_domain_id+0x55 (section: .text.iommu_max_domain_id) -> acpi_table_parse_keyp (section: .init.text)
> 
> 
> acpi_table_parse_keyp() is marked as __init. But this patch causes the
> intel iommu driver to call it from a runtime function.
> 
> int __init_or_acpilib
> acpi_table_parse_keyp(enum acpi_keyp_type id,
>                       acpi_tbl_entry_handler_arg handler_arg, void *arg)
> {
>         return __acpi_table_parse_entries(ACPI_SIG_KEYP,
>                                           sizeof(struct acpi_table_keyp),
> id,
>                                           NULL, handler_arg, arg, 0);
> }

Is it better we configure ACPI table as library, so that drivers could
use it freely at runtime? tdx-host also uses this function.

--------8<--------

diff --git a/drivers/iommu/intel/Kconfig b/drivers/iommu/intel/Kconfig
index 5471f814e073..55188d6d38bb 100644
--- a/drivers/iommu/intel/Kconfig
+++ b/drivers/iommu/intel/Kconfig
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 # Intel IOMMU support
 config DMAR_TABLE
+       select ACPI_TABLE_LIB
        bool

 config DMAR_PERF