Re: [PATCH] device-dax: map dax memory as decrypted in CoCo guests

[Gupta, Pankaj]

On 9/10/2024 3:00 PM, Gupta, Pankaj wrote:
> On 8/26/2024 11:35 PM, Kevin Loughlin wrote:
> > > How can I test this? Can I test it with virtio-pmem device?
> >
> > Correct. Assuming the CoCo guest accesses some virtio-pmem device in
> > devdax mode, mmapping() this virtio-pmem device's memory region
> > results in the guest and host reading the same (plaintext) values from
> > the region.
>
> I tried to test the daxdev with virtio-pmem but getting the below error 
> (just tried without this patch)
>
> root@ubuntu:/home/amd# ndctl list -N
> {
>    "dev":"namespace0.0",
>    "mode":"devdax",
>    "map":"dev",
>    "size":1054867456,
>    "uuid":"c8b15ce6-0c8f-4a1a-ada6-b19a90bdf1bb",
>    "numa_node":0
> }
>
> root@ubuntu:cat /dev/zero | daxio --output=/dev/namespace0.0
> daxio: neither input or output is device dax
>
> Could you please share the instructions (to test with virtio-pmem or 
> Qemu). If not, still okay.

Ah by mistake pressed entered early.

Just want to see the behavior on a SEV system with daxdev (maybe above 
virtio-pmem or other emulated device) and see how this patch helps.


Best regards,
Pankaj