Re: [Bug 219609] File corruptions on SSD in 1st M.2 socket of AsRock X600M-STX + Ryzen 8700G

[Christoph Hellwig]

On Fri, Jan 17, 2025 at 10:51:09AM +0100, Thorsten Leemhuis wrote:
> By booting with 'ignore_loglevel dyndbg="file drivers/pci/* +p"' I
> suppose? No, that is not printed (but other debug lines from the pci
> code are).
> 
> Side note: that "PCI-DMA: Using software bounce buffering for IO
> >> (SWIOTLB)" message does show up on two other AMD machines I own as
> well. One also has a Ryzen 8000, the other one a much older one.
> 
> And BTW a few bits of the latest development in the bugzilla ticket
> (https://bugzilla.kernel.org/show_bug.cgi?id=219609 ):
> 
> * iommu=pt and amd_iommu=off seems to work around the problem (in
> addition to disabling the iommu in the BIOS setup).

That suggests the problem is related to the dma-iommu code, and
my strong suspect is the swiotlb bounce buffering for untrusted
device.  If you feel adventurous, can you try building a kernel
where dev_use_swiotlb() in drivers/iommu/dma-iommu.c is hacked
to always return false?