[vfio-users] Host hard lockups

[vfio]

Thanks for the suggestions. I'm definitely not running out of RAM; the
host has 32GB and I've lowered the guest assignment to 8GB. I also have
a constant RAM use monitor that never shows anything near capacity (even
in the cases where the guest has frozen but the adjacent CPU monitor on
the host has not yet frozen).

I have a minor update on the issue.

I noticed that the symptoms of the freeze are very similar to the
freezes I sometimes get when shutting down the guest. After searching
the archives, I decided to try enabling MSI for the Titan X in the Win10
guest. This did indeed stop the freezes at shutdown time. I've been
using the guest for 10 days since my original post. During this time I
experienced only one freeze, but I was not nearby at the time so it's
hard to say if the guest caused it.

I still sometimes get similar freezes when starting up the machine after
it has already been shutdown once during the host session. In these
cases, I've noticed that lspci shows that my USB3 PCIe card is missing
all of its details and displays an error. I have not yet saved this
error message since it happens so infrequently in my use that I don't
care too much about this particular freeze.

Random question: does it matter that my host OS boots using
compatibility mode (i.e., not UEFI)? The guest machine is using OVMF.

One of the problems with debugging this is that it's hard to tell if the
problem was fixed due to the odd random distribution of the freezes. I
will provide more updates if the situation changes.

Thanks.