[Qemu-devel] [Bug 1811862] [NEW] microcode version stays 0x1 even if -cpu host is used

[Michael Ablassmeier]

Public bug reported:

The microcode version of my host cpu has the following version:

grep microcode /proc/cpuinfo | head -1
microcode       : 0x3d

while trying to run ESXi in an nested VM, the boot bailed out with
error message that at least microcode version 0x19 is needed. It 
seems they have introduced such a check on certain CPU types.

The VM in question is using the "host-passthrough" option in libvirt
and the qemu command line reads as this:

21172 ?        Sl     0:09 /usr/libexec/qemu-kvm -name guest=hpe-env-
client1,debug-threads=on -S -object
secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-33
-hpe-env-client1/master-key.aes -machine pc-i440fx-
rhel7.6.0,accel=kvm,usb=off,dump-guest-core=off -cpu host <rest
stripped>

Running a regular Linux VM with `host-passthrough` shows that the
microcode version is still reported as 0x1.

Within the VM:

address@hidden ~]# cat /proc/cpuinfo 
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 63
model name      : Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz
stepping        : 2
microcode       : 0x1
cpu MHz         : 2397.222


My impression is qemu should copy the hosts microcode version in this case?

Running Qemu von RHEl8 beta here.

address@hidden ~]# /usr/libexec/qemu-kvm --version
QEMU emulator version 2.12.0 (qemu-kvm-2.12.0-41.el8+2104+3e32e6f8)

** Affects: qemu
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1811862

Title:
  microcode version stays 0x1 even if -cpu host is used

Status in QEMU:
  New

Bug description:
  The microcode version of my host cpu has the following version:

  grep microcode /proc/cpuinfo | head -1
  microcode       : 0x3d

  while trying to run ESXi in an nested VM, the boot bailed out with
  error message that at least microcode version 0x19 is needed. It 
  seems they have introduced such a check on certain CPU types.

  The VM in question is using the "host-passthrough" option in libvirt
  and the qemu command line reads as this:

  21172 ?        Sl     0:09 /usr/libexec/qemu-kvm -name guest=hpe-env-
  client1,debug-threads=on -S -object
  secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-33
  -hpe-env-client1/master-key.aes -machine pc-i440fx-
  rhel7.6.0,accel=kvm,usb=off,dump-guest-core=off -cpu host <rest
  stripped>

  Running a regular Linux VM with `host-passthrough` shows that the
  microcode version is still reported as 0x1.

  Within the VM:

  address@hidden ~]# cat /proc/cpuinfo 
  processor       : 0
  vendor_id       : GenuineIntel
  cpu family      : 6
  model           : 63
  model name      : Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz
  stepping        : 2
  microcode       : 0x1
  cpu MHz         : 2397.222

  
  My impression is qemu should copy the hosts microcode version in this case?

  Running Qemu von RHEl8 beta here.

  address@hidden ~]# /usr/libexec/qemu-kvm --version
  QEMU emulator version 2.12.0 (qemu-kvm-2.12.0-41.el8+2104+3e32e6f8)

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