Hi Jason,
On Tue, 29 Nov 2022, Jason Gunthorpe wrote:
Provide a mock kernel module for the iommu_domain that allows it to run
without any HW and the mocking provides a way to directly validate that
the PFNs loaded into the iommu_domain are correct. This exposes the access
kAPI toward userspace to allow userspace to explore the functionality of
pages.c and io_pagetable.c
The mock also simulates the rare case of PAGE_SIZE > iommu page size as
the mock will operate at a 2K iommu page size. This allows exercising all
of the calculations to support this mismatch.
This is also intended to support syzkaller exploring the same space.
However, it is an unusually invasive config option to enable all of
this. The config option should not be enabled in a production kernel.
Tested-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx> # s390
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Replaying to and old email, after noticing commit 8541323285994528
("iommufd: Add missing IOMMUFD_DRIVER kconfig for the selftest") in
v6.9-rc5.
--- a/drivers/iommu/iommufd/Kconfig
+++ b/drivers/iommu/iommufd/Kconfig
@@ -10,3 +10,15 @@ config IOMMUFD
it relates to managing IO page tables that point at user space memory.
If you don't know what to do here, say N.
+
+if IOMMUFD
+config IOMMUFD_TEST
+ bool "IOMMU Userspace API Test support"
+ depends on DEBUG_KERNEL
+ depends on FAULT_INJECTION
+ depends on RUNTIME_TESTING_MENU
+ default n
+ help
+ This is dangerous, do not enable unless running
+ tools/testing/selftests/iommu
+endif
How dangerous is this?
I.e. is it now unsafe to run an allyesconfig or allmodconfig kernel?
Probably this symbol should be tristate?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
