linux-kernel - Re: [PATCH] iommufd: fix selftest link dependency on amdv1 driver

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-Id: <beb85629-4912-4279-b025-a7debd1dfc6a@app.fastmail.com>
Date: Wed, 24 Dec 2025 11:17:13 +0100
From: "Arnd Bergmann" <arnd@...db.de>
To: "Jason Gunthorpe" <jgg@...pe.ca>, "Arnd Bergmann" <arnd@...nel.org>
Cc: "Kevin Tian" <kevin.tian@...el.com>, "Joerg Roedel" <joro@...tes.org>,
 "Will Deacon" <will@...nel.org>, "Samiullah Khawaja" <skhawaja@...gle.com>,
 "Robin Murphy" <robin.murphy@....com>, "Nicolin Chen" <nicolinc@...dia.com>,
 "Baolu Lu" <baolu.lu@...ux.intel.com>,
 "Pranjal Shrivastava" <praan@...gle.com>, "Yi Liu" <yi.l.liu@...el.com>,
 iommu@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iommufd: fix selftest link dependency on amdv1 driver

On Wed, Dec 24, 2025, at 02:52, Jason Gunthorpe wrote:
> On Tue, Dec 23, 2025 at 10:51:22PM +0100, Arnd Bergmann wrote:
>> From: Arnd Bergmann <arnd@...db.de>
>> 
>> When CONFIG_AMD_IOMMU is disabled, the selftest runs into a link failure:
>> 
>> aarch64-linux-ld: drivers/iommu/iommufd/selftest.o: in function `mock_domain_alloc_pgtable.isra.0':
>> selftest.c:(.text+0x1590): undefined reference to `pt_iommu_amdv1_init'
>> aarch64-linux-ld: drivers/iommu/iommufd/selftest.o:(.rodata+0x280): undefined reference to `pt_iommu_amdv1_map_pages'
>> aarch64-linux-ld: drivers/iommu/iommufd/selftest.o:(.rodata+0x288): undefined reference to `pt_iommu_amdv1_unmap_pages'
>> aarch64-linux-ld: drivers/iommu/iommufd/selftest.o:(.rodata+0x2b0): undefined reference to `pt_iommu_amdv1_iova_to_phys'
>> aarch64-linux-ld: drivers/iommu/iommufd/selftest.o:(.rodata+0x2d8): undefined reference to `pt_iommu_amdv1_read_and_clear_dirty'
>> 
>> Change the top-level function to skip all the amdv1 tests in this
>> configuration.
>
> kconfig shouldn't let this build happen:
>
> config IOMMUFD_TEST
>         bool "IOMMU Userspace API Test support"
>         depends on DEBUG_KERNEL
>         depends on FAULT_INJECTION
>         depends on RUNTIME_TESTING_MENU
>         depends on IOMMU_PT_AMDV1
>         select IOMMUFD_DRIVER
>
> I think this is more fall out from Geert's change to make GENERIC_PT 
> unselectable, the 'depends on' is no longer enough??
>
> I guess the right fix is to add a "select GENERIC_PT" above, does that
> work for you?

No, it's already set.

The configuration that had the build failure contains

CONFIG_ARM64=y
# CONFIG_AMD_IOMMU is not set
CONFIG_GENERIC_PT=y
CONFIG_IOMMU_PT=m
CONFIG_IOMMU_PT_AMDV1=m
CONFIG_IOMMUFD=y
CONFIG_IOMMUFD_TEST=y

I suspect this is because IOMMUFD_TEST is 'bool' and can be enabled
even when its dependencies are =m, but if the test code is built-in,
it can't actually link.

This should be fixable using

       depends on IOMMU_PT_AMDV1=y || IOMMUFD=IOMMU_PT_AMDV1

or by forcing the iommufd code to be a loadable module when
IOMMU_PT_AMDV=m, e.g. through

config IOMMUFD
      depends on IOMMU_PT_AMDV1 || !IOMMU_PT_AMDV1 || !RUNTIME_TESTING_MENU

A cleaner approach might be to split out IOMMUFD_TEST into a separate
module rather than including it inside of the IOMMUFD module,
but that is likely much more work.

      Arnd