[pve-devel] [PATCH common/qemu-server 0/2] vm start: catch outdated Zen 5 firmware

[Markus Frank]

Hi,

On 2026-01-19 17:01, Fiona Ebner wrote:
> NOTE: Needs to still be tested on an actually affected system!

I tested both patches with the kernel 6.17.9 on my affected system (Ryzen 9 9900X, Gigabyte X870 AORUS ELITE WIFI7, Firmware-Version: F8).


Without the patches I get this error with kernel 6.17.9 when using CPU type 'EPYC':

kvm: warning: host doesn't support requested feature: CPUID[eax=07h,ecx=00h].EBX.rdseed [bit 18]
kvm: Host doesn't support requested features
TASK ERROR: start failed: QEMU exited with code 1


With the patches applied I get the same error with more context:

kvm: warning: host doesn't support requested feature: CPUID[eax=07h,ecx=00h].EBX.rdseed [bit 18]
WARN: On Zen 5 systems, the rdseed CPU flag might not be available when the CPU firmware is outdated. See:
https://security-tracker.debian.org/tracker/CVE-2025-62626
https://pve.proxmox.com/pve-docs/chapter-sysadmin.html#sysadmin_firmware_cpu
kvm: Host doesn't support requested features
TASK ERROR: start failed: QEMU exited with code 1


Tested-by: Markus Frank <m.frank at proxmox.com>

> 
> With the 6.17.9 kernel, the rdseed feature bit is not available for
> some Zen 5 host CPUs anymore unless the firmware is new enough. QEMU
> will complain about the missing feature bit upon VM start. Add some
> context to the QEMU error message if the host is Zen 5 (or 6, same CPU
> family number, but the warning message already states 'Zen 5'
> explicitly and probably the feature bit won't be missing in the first
> place).
> 
> pve-common:
> 
> Fiona Ebner (1):
>    procfs tools: cpuinfo: also return CPU vendor and family
> 
>   src/PVE/ProcFSTools.pm | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> 
> qemu-server:
> 
> Fiona Ebner (1):
>    vm start: catch outdated Zen 5 firmware
> 
>   src/PVE/QemuServer.pm | 13 +++++++++++++
>   1 file changed, 13 insertions(+)
> 
> 
> Summary over all repositories:
>    2 files changed, 19 insertions(+), 0 deletions(-)
>