On Tue, Apr 06, 2021 at 16:31:32 +0100, Daniel Berrange wrote:
> 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@xxxxxxxxxx>
> ---
> 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.
Any range limits or uniqueness requirements worth mentioning?
> +
> :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;
ABI stability check is missing.
