1. Please describe the problem:
It's currently possible for malicious devices to access stable data content. Having CONFIG_IOMMU_DEFAULT_DMA_STRICT=y would force proper IOMMU TLB invalidation, preventing this from happening.

This setting is recommended upstream: https://github.com/torvalds/linux/blob/master/kernel/configs/hardening.config#L72

The only possible issue would be that it might affect the performances on some platforms with cursed drivers.

2. What is the Version-Release number of the kernel:

N/A

3. Did it work previously in Fedora? If so, what kernel version did the issue
   *first* appear?  Old kernels are available for download at
   https://koji.fedoraproject.org/koji/packageinfo?packageID=8 :

No.

4. Can you reproduce this issue? If so, please provide the steps to reproduce
   the issue below:

Yes, rebuild with CONFIG_IOMMU_DEFAULT_DMA_STRICT, notice that nothing breaks on my machine™. No need to rebuild the kernel if you're lazy, this option is equivalent to `iommu.passthrough=0 iommu.strict=1`


5. Does this problem occur with the latest Rawhide kernel? To install the
   Rawhide kernel, run ``sudo dnf install fedora-repos-rawhide`` followed by
   ``sudo dnf update --enablerepo=rawhide kernel``:

N/A

6. Are you running any modules that not shipped with directly Fedora's kernel?:

N/A

7. Please attach the kernel logs. You can get the complete kernel log
   for a boot with ``journalctl --no-hostname -k > dmesg.txt``. If the
   issue occurred on a previous boot, use the journalctl ``-b`` flag.

N/A

Reproducible: Always