[edk2-devel] OVMF and SMBIOS

[Laszlo Ersek]

On 05/28/19 17:18, Tomas Pilar (tpilar) wrote:
> Hi,
> 
> I am trying to create kvm instance using libvirt and Qemu and OVMF that also has SMBIOS included. My current version of Qemu only supports type 0 and type 1 SMBIOS tables so I specify those. However, when I use smbiosview in the UEFI shell, I get back "SMBIOS not found".
> 
> I attach my current libvirt xml specification for the kvm host.
> 
> Does anyone have any immediate ideas?

The SMBIOS fw_cfg interface between QEMU and guest firmware was reworked
in the QEMU v2.1.0 release (primarily in commit c97294ec1b9e, "SMBIOS:
Build aggregate smbios tables and entry point", 2014-05-05).

If you use an earlier QEMU release, or else you use a machine type
earlier than pc-i440fx-2.1, then the new SMBIOS fw_cfg interface is not
exposed to guest firmware.

And, upstream OVMF never gained patches for the "legacy" SMBIOS fw_cfg
interface. I had posted patches for that in 2013, but they were not
accepted. The thread starts here:

[edk2] [PATCH 0/3] OvmfPkg: basic SMBIOS support on QEMU
https://www.mail-archive.com/edk2-devel@lists.sourceforge.net/msg02917.html

We (RH) carried forward these patches for quite some time in RHEL7 and
(IIRC) Fedora as well, but QEMU v2.1.0 was released in Aug 2014 if I
read the git log right, and so we too dropped the downstream-only
patches at some point, in favor of the new interface.

Based on your libvirt domain xml... It looks likely that you use the
qemu-kvm package that is part of base RHEL7. That package is based on
upstream QEMU 1.5.3, and so it indeed lacks support for the "new" SMBIOS
interface. If you can use CentOS, you could try the qemu-kvm-ev package
instead. (That one is based on upstream 2.12.)

Alternatively, you could check the "OVMF-20160202-2.gitd7c0dfa.el7"
package (or earlier), which should (a) still include the
above-referenced patches, and (b) still run on the 1.5.3-based qemu-kvm
emulator. (Later OVMF packages would only provide the SMM_REQUIRE
firmware binary, which does not boot on the 1.5.3-based qemu-kvm emulator.)

Thanks
Laszlo

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