focal: qemu 1:4.2-3ubuntu6.15, libvirt 6.0.0-0ubuntu8.8

# qemu-system-x86_64 -cpu ? | grep EPYC
x86 EPYC (alias configured by machine type)
x86 EPYC-IBPB (alias of EPYC-v2)
x86 EPYC-Rome (alias configured by machine type)
x86 EPYC-Rome-v1 AMD EPYC-Rome Processor
x86 EPYC-v1 AMD EPYC Processor
x86 EPYC-v2 AMD EPYC Processor (with IBPB)
x86 EPYC-v3 AMD EPYC Processor

# virsh domcapabilities
    <mode name='host-model' supported='yes'>
      <model fallback='forbid'>EPYC-Rome</model>
      <vendor>AMD</vendor>
      <feature policy='require' name='pcid'/>
      <feature policy='require' name='x2apic'/>
      <feature policy='require' name='tsc-deadline'/>
      <feature policy='require' name='hypervisor'/>
      <feature policy='require' name='tsc_adjust'/>
      <feature policy='require' name='erms'/>
      <feature policy='require' name='vaes'/>
      <feature policy='require' name='vpclmulqdq'/>
      <feature policy='require' name='spec-ctrl'/>
      <feature policy='require' name='stibp'/>
      <feature policy='require' name='arch-capabilities'/>
      <feature policy='require' name='ssbd'/>
      <feature policy='require' name='xsaves'/>
      <feature policy='require' name='cmp_legacy'/>
      <feature policy='require' name='invtsc'/>
      <feature policy='require' name='amd-ssbd'/>
      <feature policy='require' name='virt-ssbd'/>
      <feature policy='require' name='rdctl-no'/>
      <feature policy='require' name='skip-l1dfl-vmentry'/>
      <feature policy='require' name='mds-no'/>
      <feature policy='require' name='pschange-mc-no'/>
    </mode>

After:

# qemu-system-x86_64 -cpu ? | grep EPYC
x86 EPYC (alias configured by machine type)
x86 EPYC-IBPB (alias of EPYC-v2)
x86 EPYC-Milan (alias configured by machine type)
x86 EPYC-Milan-v1 AMD EPYC-Milan Processor
x86 EPYC-Rome (alias configured by machine type)
x86 EPYC-Rome-v1 AMD EPYC-Rome Processor
x86 EPYC-Rome-v2 AMD EPYC-Rome Processor
x86 EPYC-v1 AMD EPYC Processor
x86 EPYC-v2 AMD EPYC Processor (with IBPB)
x86 EPYC-v3 AMD EPYC Processor

    <mode name='host-model' supported='yes'>
      <model fallback='forbid'>EPYC-Milan</model>
      <vendor>AMD</vendor>
      <feature policy='require' name='x2apic'/>
      <feature policy='require' name='tsc-deadline'/>
      <feature policy='require' name='hypervisor'/>
      <feature policy='require' name='tsc_adjust'/>
      <feature policy='require' name='vaes'/>
      <feature policy='require' name='vpclmulqdq'/>
      <feature policy='require' name='spec-ctrl'/>
      <feature policy='require' name='stibp'/>
      <feature policy='require' name='arch-capabilities'/>
      <feature policy='require' name='ssbd'/>
      <feature policy='require' name='cmp_legacy'/>
      <feature policy='require' name='invtsc'/>
      <feature policy='require' name='virt-ssbd'/>
      <feature policy='require' name='rdctl-no'/>
      <feature policy='require' name='skip-l1dfl-vmentry'/>
      <feature policy='require' name='mds-no'/>
      <feature policy='require' name='pschange-mc-no'/>
      <feature policy='disable' name='invpcid'/>
      <feature policy='disable' name='pku'/>
      <feature policy='disable' name='fsrm'/>
      <feature policy='disable' name='svme-addr-chk'/>
    </mode>

Still working as expected