Re: [libvirt] [PATCH 4/5] conf: include x86 microcode version in virsh capabilities

From: Paolo Bonzini <pbonzini(a)redhat.com&gt; A microcode update can cause the CPUID bits to change; an example from the past was the update that disabled TSX on several Haswell and Broadwell machines. In order to track the x86 microcode version in the QEMU capabilities, we have to fetch it and store it in the host CPU. This also makes the version visible in "virsh capabilities", which is a nice side effect. Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com&gt; Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com&gt; --- src/conf/cpu_conf.c | 14 ++++++++++++++ src/conf/cpu_conf.h | 1 + src/cpu/cpu_x86.c | 9 +++++++++ 3 files changed, 24 insertions(+)

@@ -382,6 +384,14 @@ virCPUDefParseXML(xmlXPathContextPtr ctxt, goto cleanup; } VIR_FREE(arch); + + if (virXPathBoolean("boolean(./microcode[1]/@version)", ctxt) > 0 && + virXPathUInt("string(./microcode[1]/@version)", ctxt, + &def->microcodeVersion) < 0) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("invalid microcode version")); + goto cleanup; + } } if (!(def->model = virXPathString("string(./model[1])", ctxt)) && @@ -720,6 +730,10 @@ virCPUDefFormatBuf(virBufferPtr buf, if (formatModel && def->vendor) virBufferEscapeString(buf, "<vendor>%s</vendor>\n", def->vendor); + if (def->type == VIR_CPU_TYPE_HOST && def->microcodeVersion)

+ virBufferAsprintf(buf, "<microcode version='%u'/>\n", + def->microcodeVersion); +