Re: [libvirt] [PATCH v4 3/8] libxl: error out on not supported CPU mode, instead of silently ignoring

On 02/08/2018 03:58 PM, Marek Marczykowski-Górecki wrote: > This change make libvirt XML with plain <cpu> element invalid for libxl, > which affect not only upcoming CPUID support, but also NUMA. In fact, > default mode 'custom' does not match what the driver actually does, so > it was a bug. Adjust xenconfig driver accordingly. > > But nevertheless this commit break some configurations that were working > before. > > --- > Changes since v3: > - fix vnuma tests (nested HVM implicitly enabled there) > Changes since v2: > - change separated from 'libxl: add support for CPUID features policy' > --- > src/libxl/libxl_conf.c | 10 ++++++++-- > src/xenconfig/xen_xl.c | 1 +- > tests/xlconfigdata/test-fullvirt-vnuma-autocomplete.cfg | 1 +- > tests/xlconfigdata/test-fullvirt-vnuma-autocomplete.xml | 2 +- > tests/xlconfigdata/test-fullvirt-vnuma-nodistances.cfg | 1 +- > tests/xlconfigdata/test-fullvirt-vnuma-nodistances.xml | 2 +- > tests/xlconfigdata/test-fullvirt-vnuma-partialdist.cfg | 1 +- > tests/xlconfigdata/test-fullvirt-vnuma-partialdist.xml | 2 +- > tests/xlconfigdata/test-fullvirt-vnuma.cfg | 1 +- > tests/xlconfigdata/test-fullvirt-vnuma.xml | 2 +- > 10 files changed, 17 insertions(+), 6 deletions(-) > > diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c > index 8cced29..66956a7 100644 > --- a/src/libxl/libxl_conf.c > +++ b/src/libxl/libxl_conf.c > @@ -355,11 +355,17 @@ libxlMakeDomBuildInfo(virDomainDefPtr def, > def->features[VIR_DOMAIN_FEATURE_ACPI] == > VIR_TRISTATE_SWITCH_ON); > - if (caps && > - def->cpu && def->cpu->mode == (VIR_CPU_MODE_HOST_PASSTHROUGH)) { > + if (caps && def->cpu) { > bool hasHwVirt = false; > bool svm = false, vmx = false; > + if (def->cpu->mode != VIR_CPU_MODE_HOST_PASSTHROUGH) { > + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, > + _("unsupported cpu mode '%s'"), > + virCPUModeTypeToString(def->cpu->mode)); > + return -1; > + } It looks like we never answered my question from V3, i.e. should we change the default mode in the post-parse callback if NUMA or CPU features are defined within <cpu>?

It sure feels like such configuration tweaks and error checks should be handled in the parsing phase, similar to qemuDomainDefVcpusPostParse() and qemuDomainDefCPUPostParse() in the qemu driver. I think danpb is vaguely familiar with this series and can help answer that question. Daniel, do you have an opinion? Or a general comment about guidelines for checking/tweaking config in parse phase vs domain start phase?