Re: unable to find any master var store for loader error

13 Oct 2020


      On 10/13/20 2:25 PM, daggs wrote:
...
Greetings Michal,
...
Sent: Tuesday, October 13, 2020 at 2:51 PM
From: "Michal Privoznik" <mprivozn@redhat.com>
To: "daggs" <daggs@gmx.com>, libvirt-users@redhat.com
Subject: Re: unable to find any master var store for loader error
Hey,
I'll paste the interesting part of domain XML here so that it doesn't
get lost:
<os>
      <type arch='x86_64' machine='pc-q35-5.0'>hvm</type>
      <loader readonly='yes'
type='pflash'>/usr/share/edk2-ovmf/OVMF_CODE.fd</loader>
      <nvram>/var/lib/libvirt/qemu/nvram/vm1_VARS.fd</nvram>
      <boot dev='hd'/>
    </os>
And then in qemu.conf you define the pair:
nvram = [
  "/usr/share/edk2-ovmf/OVMF_CODE.fd:/usr/share/edk2-ovmf/OVMF_VARS.fd",
  "/usr/share/edk2-ovmf/OVMF_CODE.secboot.fd:/usr/share/edk2-ovmf/OVMF_VARS.secboot.fd"
]
But as the comment in qemu.conf (just above your line) says, this is
ignored if FW metadata files exist which is exactly your case and this bug:
https://bugzilla.redhat.com/show_bug.cgi?id=1763477
For your convenience you can switch to <os firmware='efi'/> (the
<loader/> element will be removed automatically) or if you insist on
using the old style then provide @template attribute to <nvram/>:
<nvram
template="/usr/share/edk2-ovmf/OVMF_CODE.fd">/var/lib/libvirt/qemu/nvram/vm1_VARS.fd</nvram>
There is an internal list that is still consulted when finding matching
_VARS fails, but your path is not on it:
https://gitlab.com/libvirt/libvirt/-/blob/master/src/qemu/qemu_conf.c#L98
But it exists mostly to give distros enough time to switch to FW
descriptors.
Michal
thanks for the detailed explanation, I wanted to be sure I understand. the following is needed to be done:
1. replace this:
<os>
   <type arch='x86_64' machine='pc-q35-5.0'>hvm</type>
   <loader readonly='yes' type='pflash'>/usr/share/edk2-ovmf/OVMF_CODE.fd</loader>
   <nvram>/var/lib/libvirt/qemu/nvram/vm1_VARS.fd</nvram>
   <boot dev='hd'/>
</os>
to this:
<os firmware='efi'/>
   <type arch='x86_64' machine='pc-q35-5.0'>hvm</type>
   <boot dev='hd'/>
</os>
Here, nvram will be generated, but if you want some other path than 
libvirt would generate you can provide it under <nvram/>. Yes. But 
you're using the default path anyway.
...
2. patch qemu_conf.c to include the custom paths of my fd files?
There is a third option. Save the following under 
/etc/qemu/firmware/50-my-ovmf.json:

{
     "description": "UEFI firmware for x86_64",
     "interface-types": [
         "uefi"
     ],
     "mapping": {
         "device": "flash",
         "executable": {
             "filename": "/usr/share/edk2-ovmf/OVMF_CODE.fd",
             "format": "raw"
         },
         "nvram-template": {
             "filename": "/usr/share/edk2-ovmf/OVMF_VARS.fd",
             "format": "raw"
         }
     },
     "targets": [
         {
             "architecture": "x86_64",
             "machines": [
                 "pc-i440fx-*",
                 "pc-q35-*"
             ]
         }
     ],
     "features": [
         "acpi-s3",
         "amd-sev",
         "verbose-dynamic"
     ],
     "tags": [

     ]
}


Michal