Re: Serious AMD-Vi issue

[Elliott Mitchell <ehem+xen@xxxxxxx>]

On Mon, Jan 27, 2025 at 10:44:33AM +0100, Roger Pau Monné wrote:
> On Fri, Jan 24, 2025 at 01:26:23PM -0800, Elliott Mitchell wrote:
> > 
> > In fact what seems a likely reproduction on Intel hardware is the Intel
> > sound card issue.  I notice that issue occurs when sound *starts*
> > playing.  When a sound device starts, its buffers would be empty and the
> > first DMA request would be turned around with minimal latency.  In such
> > case this matches the Samsung SATA devices handling DMA with low
> > latency.
> 
> Can you reproduce the data loss issue without using RAID in Linux?
> You can use fio with verify or similar to stress test it.

This seems rather unlikely.  The first reportter tried without software
RAID and didn't observe the issue.  If the problem occurred without
software RAID, there would be massive numbers of data loss reports.

> Can you reproduce if dom0 is PVH instead of PV?

Haven't gotten Domain 0 PVH to work yet.  I was planning to try again
when Debian updates to 4.20, but until then this isn't working.

> Can you reproduce with dom0-iommu=strict mode in the Xen command line?

Alas, this is now a definite "yes".  Took a bunch of waiting, but now
confirmed to occur with "dom0-iommu=strict".


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