[PATCH] iommufd: fix selftest link dependency on amdv1 driver

[PATCH] iommufd: fix selftest link dependency on amdv1 driver

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.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.

Fixes: e93d5945ed5b ("iommufd: Change the selftest to use iommupt instead of xarray")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/iommu/iommufd/selftest.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
index 550ff36dec3a..4d04d7642b1b 100644
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@ -479,6 +479,11 @@ mock_domain_alloc_pgtable(struct device *dev,
 	}
 
 	case MOCK_IOMMUPT_AMDV1: {
+		if (!IS_ENABLED(CONFIG_AMD_IOMMU)) {
+			rc = -EOPNOTSUPP;
+			goto err_free;
+		}
+
 		struct pt_iommu_amdv1_cfg cfg = {};
 
 		cfg.common.hw_max_vasz_lg2 = 64;
-- 
2.39.5

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

[Jason Gunthorpe]

On Tue, Dec 23, 2025 at 10:51:22PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.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?

Jason

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

[Arnd Bergmann]

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@arndb.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

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

[Jason Gunthorpe]

On Wed, Dec 24, 2025 at 11:17:13AM +0100, Arnd Bergmann wrote:
> 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@arndb.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.

Okay, that makes more sense..

> This should be fixable using
> 
>        depends on IOMMU_PT_AMDV1=y || IOMMUFD=IOMMU_PT_AMDV1

This is probably the best option, can you check it with the
problematic .config?

> 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

Because we don't want this restriction for production builds..

> 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.

I think there are cross calls that would make that difficult :\

Jason