[libvirt] [libvirt-glib 2/3] Add GVirConfigDomainHostdevPci

[Zeeshan Ali (Khattak)]

Hi,

>> + */
>> +GVirConfigDomainHostdevPci *gvir_config_domain_hostdev_pci_new(void)
>> +{
>> +    GVirConfigObject *object;
>> +
>> +    object = gvir_config_object_new(GVIR_CONFIG_TYPE_DOMAIN_HOSTDEV_PCI,
>> +                                    "hostdev", NULL);
>> +    gvir_config_object_set_attribute(object, "mode", "subsystem", NULL);
>> +    gvir_config_object_set_attribute(object, "type", "pci", NULL);
>> +
>> +    return GVIR_CONFIG_DOMAIN_HOSTDEV_PCI(object);
>> +}
>> +
>> +/**
>> + * gvir_config_domain_hostdev_pci_new_from_xml:
>> + * @xml: xml data to create the host device from
>> + * @error: return location for a #GError, or NULL
>> + *
>> + * Creates a new #GVirConfigDomainHostdevPci with a reference count of 1.
>> + * The host device object will be created using the XML description stored
>> + * in @xml. This is a fragment of libvirt domain XML whose root node is
>> + * <hostdev>.
>> + *
>> + * Returns: a new #GVirConfigDomainHostdevPci, or NULL if @xml failed to
>> + * be parsed.
>> + */
>> +GVirConfigDomainHostdevPci *gvir_config_domain_hostdev_pci_new_from_xml(const gchar *xml,
>> +                                                                        GError **error)
>> +{
>> +    GVirConfigObject *object;
>> +
>> +    object = gvir_config_object_new_from_xml(GVIR_CONFIG_TYPE_DOMAIN_HOSTDEV_PCI,
>> +                                             "hostdev", NULL, xml, error);
>> +    if (*error != NULL)
>> +        return NULL;
>> +
>> +    if (g_strcmp0(gvir_config_object_get_attribute(object, NULL, "type"), "pci") != 0) {
>> +        g_object_unref(G_OBJECT(object));
>> +        g_return_val_if_reached(NULL);
>> +    }
>> +
>> +    return GVIR_CONFIG_DOMAIN_HOSTDEV_PCI(object);
>> +}
>> +
>> +void gvir_config_domain_hostdev_pci_set_address(GVirConfigDomainHostdevPci *hostdev,
>> +                                                GVirConfigDomainAddressPci *address)
>> +{
>> +    GVirConfigObject *source;
>> +    GVirConfigObject *addr_object;
>> +    xmlNodePtr node;
>> +    xmlAttrPtr attr;
>> +
>> +    g_return_if_fail(GVIR_CONFIG_IS_DOMAIN_HOSTDEV_PCI(hostdev));
>> +    g_return_if_fail(GVIR_CONFIG_IS_DOMAIN_ADDRESS_PCI(address));
>> +    addr_object = GVIR_CONFIG_OBJECT(address);
>> +    node = gvir_config_object_get_xml_node(addr_object);
>> +    g_return_if_fail(node != NULL);
>> +
>> +    source = gvir_config_object_replace_child(GVIR_CONFIG_OBJECT(hostdev),
>> +                                              "source");
>> +    /* We can't just use GVirConfigDomainAddressPci's node, as is, since it
>> +     * contains a 'type' attribute that's not valid in this context. So we
>> +     * create a copy for our use and just delete the 'type' node from it.
>> +     */
>
> It took me a while to understand what this comment meant exactly, and
> why this was needed. If I followed correctly, in libvirt RelaxNG schema,
> the address for a PCI hostdev device is a 'pciaddress', which do not
> have a 'type' attribute contrary to most other addresses. This means
> that for the PCI address of a hostdev device, trying to set a 'type' attribute
> will trigger errors from libvirt when it tries to parse the domain XML.

Yeah, I tried tried with `virsh edit` and it tells me xml doesn't
confirm to schema.

> In my opinion, this is a libvirt bug that type="pci" is not accepted
> here as libvirt documentation says:
> « Device Addresses
>
> Many devices have an optional <address> sub-element to describe where
> the device is placed on the virtual bus presented to the guest.[...]
>
> Every address has a mandatory attribute type that describes which bus
> the device is on. »
>
> Maybe here things are a bit special as this address is not a direct
> child of the <hostdev> element, but is contained within a <source>
> element, but I still think it would be nicer of libvirt, and more
> consistent to accept an optional type="pci" attribute here rather than
> rejecting it. This would have spared us the ugly workaround below :(

Yeah but even if it's resolved in libvirt, we'd still want to have a
work around for older libvirt.

>> +
>> +const gchar *gvir_config_domain_hostdev_pci_get_rom(GVirConfigDomainHostdevPci *hostdev,
>> +                                                    gboolean *bar)
>> +{
>> +    xmlNodePtr hostdev_node;
>> +    xmlNodePtr rom_node;
>> +    const gchar *bar_str;
>> +
>> +    g_return_val_if_fail(GVIR_CONFIG_IS_DOMAIN_HOSTDEV_PCI(hostdev), NULL);
>> +
>> +    hostdev_node = gvir_config_object_get_xml_node(GVIR_CONFIG_OBJECT(hostdev));
>> +    g_return_val_if_fail(hostdev_node != NULL, NULL);
>> +
>> +    rom_node = gvir_config_xml_get_element(hostdev_node, "rom", NULL);
>> +    if (!rom_node || !(rom_node->children))
>> +        return NULL;
>> +
>> +    bar_str = gvir_config_xml_get_attribute_content(rom_node, "bar");
>> +    if (g_strcmp0(bar_str, "on"))
>> +        *bar = TRUE;
>> +    else
>> +        *bar = FALSE;
>> +
>> +    return (const char *) rom_node->children->content;
>
> The filename is in the file attribute, it's not in the node content
> (addressed in a patch I'm going to send by switching to using
> GVirConfigObject helpers).
>
> Regarding the API, I don't think there are other places in
> libvirt-gconfig where we set (or get) 2 things with a single
> setter/getter. Are these 2 parameters tightly coupled together?
> It seems to me we could do something similar to the <os><type>
> attributes ('arch' and 'machine'). These 2 attributes are set by 2
> separate helpers, but these helpers are in the GVirConfigOs class:
> gvir_config_domain_os_set_arch
> gvir_config_domain_os_set_machine

Both 'arch' and 'machine' are separate attributes on the 'type' node
but "bar" is an attribute of "rom" node, that I think is unlikely to
be used in isolation. If we keep this API, I think I should change
'rom' to be nullable. I see your point though and I don't have hard
feeling either way.


-- 
Regards,

Zeeshan Ali (Khattak)
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