Re: [libvirt PATCH 1/6] conf: add support for <acpi index='NNN'/> for PCI devices

PCI devices can be associated with a unique integer index that is exposed via ACPI. In Linux OS with systemd, this value is used for provide a NIC device naming scheme that is stable across changes in PCI slot configuration. Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; --- docs/formatdomain.rst | 6 +++ docs/schemas/domaincommon.rng | 73 +++++++++++++++++++++++++++++++++++ src/conf/device_conf.h | 3 ++ src/conf/domain_conf.c | 12 ++++++ 4 files changed, 94 insertions(+) diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst index 7ba32ea9c1..5db0aac77a 100644 --- a/docs/formatdomain.rst +++ b/docs/formatdomain.rst @@ -4363,6 +4363,7 @@ Network interfaces <mac address='52:54:00:5d:c7:9e'/> <boot order='1'/> <rom bar='off'/> + <acpi index='4'/> </interface> </devices> ... @@ -4389,6 +4390,11 @@ when it's in the reserved VMware range by adding a ``type="static"`` attribute to the ``<mac/>`` element. Note that this attribute is useless if the provided MAC address is outside of the reserved VMWare ranges. +:since:`Since 7.3.0`, one can set the ACPI index against network interfaces. +With some operating systems (eg Linux with systemd), the ACPI index is used +to provide network interface device naming, that is stable across changes +in PCI addresses assigned to the device.

+ :anchor:`<a id="elementsNICSVirtual"/>` Virtual network

diff --git a/src/conf/device_conf.h b/src/conf/device_conf.h index a51bdf10ee..af9a43bff2 100644 --- a/src/conf/device_conf.h +++ b/src/conf/device_conf.h @@ -159,6 +159,9 @@ struct _virDomainDeviceInfo { /* bootIndex is only used for disk, network interface, hostdev * and redirdev devices */ unsigned int bootIndex; + /* Valid for any PCI device. Can be used for NIC to get + * stable numbering in Linux */ + unsigned int acpiIndex; /* pciConnectFlags is only used internally during address * assignment, never saved and never reported. diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 1e72171586..ef921ae41a 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -6335,6 +6335,9 @@ virDomainDeviceInfoFormat(virBufferPtr buf, virBufferAddLit(buf, "/>\n"); } + if (info->acpiIndex != 0) + virBufferAsprintf(buf, "<acpi index='%u'/>\n", info->acpiIndex); + if (info->type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE || info->type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_S390) /* We're done here */ @@ -6661,6 +6664,7 @@ virDomainDeviceInfoParseXML(virDomainXMLOptionPtr xmlopt, g_autofree char *romenabled = NULL; g_autofree char *rombar = NULL; g_autofree char *aliasStr = NULL; + g_autofree char *acpiIndex = NULL; VIR_XPATH_NODE_AUTORESTORE(ctxt) virDomainDeviceInfoClear(info); @@ -6709,6 +6713,14 @@ virDomainDeviceInfoParseXML(virDomainXMLOptionPtr xmlopt, } } + acpiIndex = virXPathString("string(./acpi/@index)", ctxt); + if (acpiIndex && + virStrToLong_ui(acpiIndex, NULL, 10, &info->acpiIndex) < 0) { + virReportError(VIR_ERR_XML_ERROR, + _("Cannot parse ACPI index value '%s'"), acpiIndex); + goto cleanup; + } + if ((address = virXPathNode("./address", ctxt)) && virDomainDeviceAddressParseXML(address, info) < 0) goto cleanup;