diff --git a/nova/conf/libvirt.py b/nova/conf/libvirt.py index 4098f618611d..a7a9ee4a386c 100644 --- a/nova/conf/libvirt.py +++ b/nova/conf/libvirt.py @@ -518,7 +518,7 @@ Related options: cfg.ListOpt( 'cpu_model_extra_flags', item_type=types.String( - choices=['pcid', 'ssbd', 'virt-ssbd'], + choices=['pcid', 'ssbd', 'virt-ssbd', 'amd-ssbd', 'amd-no-ssb'], ignore_case=True, ), default=[], @@ -534,11 +534,11 @@ virtual CPU model:: cpu_model_extra_flags = pcid Currently, the choice is restricted to a few options: ``pcid``, -``ssbd``, and ``virt-ssbd`` (the options are case-insensitive, so -``PCID`` is also valid, for example). These flags are now required to -address the guest performance degradation as a result of applying the -"Meltdown" CVE fixes (``pcid``) and exposure mitigation (``ssbd`` and -``virt-ssbd``) on affected CPU models. +``ssbd``, ``virt-ssbd``, ``amd-ssbd``, and ``amd-no-ssb`` (the options +are case-insensitive, so ``PCID`` is also valid, for example). These +flags are now required to address the guest performance degradation as +a result of applying the "Meltdown" CVE fixes (``pcid``) and exposure +mitigation (``ssbd`` and related options) on affected CPU models. Note that when using this config attribute to set the 'PCID' and related CPU flags, not all virtual (i.e. libvirt / QEMU) CPU models @@ -552,13 +552,15 @@ need it: even if the host CPUs by the same name include it. I.e. 'PCID' needs to be explicitly specified when using the said virtual CPU models. -For more information about ``ssbd`` and ``virt-ssbd`` applicability, +For more information about ``ssbd`` and related options, please refer to the following security updates: https://www.us-cert.gov/ncas/alerts/TA18-141A https://www.redhat.com/archives/libvir-list/2018-May/msg01562.html +https://www.redhat.com/archives/libvir-list/2018-June/msg01111.html + For now, the ``cpu_model_extra_flags`` config attribute is valid only in combination with ``cpu_mode`` + ``cpu_model`` options. diff --git a/releasenotes/notes/libvirt-cpu-model-extra-flags-amd-ssbd-1c0d0cec14073dec.yaml b/releasenotes/notes/libvirt-cpu-model-extra-flags-amd-ssbd-1c0d0cec14073dec.yaml new file mode 100644 index 000000000000..5d8e9d54edc2 --- /dev/null +++ b/releasenotes/notes/libvirt-cpu-model-extra-flags-amd-ssbd-1c0d0cec14073dec.yaml @@ -0,0 +1,8 @@ +--- +security: + - | + The 'AMD-SSBD' and 'AMD-NO-SSB' flags have been added to the list of available + choices for the ``[libvirt]/cpu_model_extra_flags`` config option. These are + important for proper mitigation of security issues in AMD CPUs. For more + information see + https://www.redhat.com/archives/libvir-list/2018-June/msg01111.html \ No newline at end of file