@sborrill And for completeness, try pvshim (a.k.a. pv-in-pvh) using xl:

1. Download https://ftp.netbsd.org/pub/NetBSD/NetBSD-10.1/amd64/binary/kernel/netbsd-INSTALL_XEN3_DOMU.gz
2. Create /root/nbpv containing:

name = "nbpv"
type="pvh"
pvshim=1
pvshim_cmdline="pv-shim console=xen pv-linear-pt=true"
kernel = "/root/netbsd-INSTALL_XEN3_DOMU.gz"
memory = 1024

3. Boot VM successfully with xl create -c nbpv

So pv-in-pvh does work (does require pv-linear-pt=true on shim command line though).

PVH is supported just fine by the xl toolstack on XCP-ng and XenServer, so it's only the relevant glue missing in xapi to enable domain-type=pvh to work.

To demonstrate:

1. Download a NetBSD INSTALL kernel from https://ftp.netbsd.org/pub/NetBSD/NetBSD-10.1/amd64/binary/kernel/netbsd-INSTALL.gz to /root.

2. Create /root/nbpvh containing:

name = "nbpvh"
type="pvh"
kernel = "/root/netbsd-INSTALL.gz"
memory = 1024

3. Boot VM with xl create -c nbpvh

@TeddyAstie Any idea how to debug this? I'd hoped that enabling VM console output with the following might help:

xenstore-write /local/logconsole/@ /tmp/console.%d.log

With the xl toolstack and pvshim, you see the shim xen kernel start on the VM serial console before handing over to the PV domU kernel. In XCP-ng, there is no output.

@TeddyAstie Thanks, but that appears to make no difference

# xe vm-param-get uuid=82dfbfc3-d620-2aeb-8ac5-2567d44ea479 param-name=domain-type
pv-in-pvh
# xe vm-param-get uuid=82dfbfc3-d620-2aeb-8ac5-2567d44ea479 param-name=platform param-key=pvinpvh-xen-cmdline
pv-shim console=xen pv-linear-pt=true

@TeddyAstie
Yes, I tried pv-in-pvh before posting and it didn't work. The VM appears to go through the starting process and then stops.

My theory is that this is because PV_LINEAR_PT is compiled out which is required by NetBSD PV. Even prior to this you had to enable it with:
/opt/xensource/libexec/xen-cmdline --set-xen pv-linear-pt=true

With the xl tool stack as used by a NetBSD dom0, pvshim does work with the same kernel.

@gduperrey I thought I had. I was replying to that thread and the forum software prompted me to click to reload. It continued to show the contents of the thread above as I clicked to post my reply, so if it opened a new thread, I count that as a bug in the forum, not user error

Yes, I tried pv-in-pvh before posting and it didn't work. The VM appears to go through the starting process and then stops.

My theory is that this is because PV_LINEAR_PT is compiled out which is required by NetBSD PV. Even prior to this you had to enable it with:
/opt/xensource/libexec/xen-cmdline --set-xen pv-linear-pt=true

With the xl tool stack as used by a NetBSD dom0, pvshim does work with the same kernel.

I have a NetBSD VM which was fully PV, but now has been upgraded to have a kernel which supports PVH. How do I configure the VM to use the PVH device model so I can get it to run now that vanilla PV is no longer supported?

--
Stephen

@olivierlambert I have a method I can use to workaround, yes, but there's a few things that violate POLA. It appears as ACL-only cannot be used to allow snapshotting because of the need to give admin-ish access to the SR. Using resource sets and self-service does work, but having to add users, not just groups they are in, to the resource set isn't great. I was unclear about why ACLs (i.e. visibility of a VM) disappeared when removing snapshots.

@sborrill said in Permissions for users to be able to snapshot:

(related question, can an existing VM be added to a self-service resource group?)

It appears not. The Web GUI makes it look like you can by allowing you to pick a resource set but you get the following error:

  "message": "the vm is not in a resource set

Note that despite this error, the VM has now been added to the resource set and can be snapshotted (if the user is explicitly a member of the same resource set - not just in a group that is)