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Re: [libvirt] [PATCH 1/2] Add domain support for virtio channel



On Thu, Feb 18, 2010 at 01:16:02PM +0000, Matthew Booth wrote:
> On 18/02/10 12:34, Daniel P. Berrange wrote:
> > On Wed, Feb 17, 2010 at 05:11:00PM +0000, Matthew Booth wrote:
> >> Add support for virtio-serial by defining a new 'virtio' channel target type and
> >> a virtio-serial controller. Allows the following to be specified in a domain:
> >>
> >> <controller type='virtio-serial' index='0' max_ports='16' vectors='4'/>
> >> <channel type='pty'>
> >>   <target type='virtio' name='org.linux-kvm.port.0'/>
> >>   <address type='virtio-serial' controller='0' bus='0'/>
> >> </channel>
> >>
> >> * docs/schemas/domain.rng: Add virtio-serial controller and virtio channel type.
> >> * src/conf/domain_conf.[ch]: Domain parsing/serialization for virtio-serial
> >>                              controller and virtio channel.
> >> * tests/qemuxml2xmltest.c
> >>   tests/qemuxml2argvdata/qemuxml2argv-channel-virtio.xml
> >>                            : add domain xml parsing test
> >> * src/libvirt_private.syms
> >>   src/qemu/qemu_conf.c: virDomainDefAddDiskControllers() renamed to
> >>                         virDomainDefAddImplicitControllers()
> >> ---
> >>  docs/schemas/domain.rng                            |   71 +++++-
> >>  src/conf/domain_conf.c                             |  234 +++++++++++++++++---
> >>  src/conf/domain_conf.h                             |   25 ++-
> >>  src/libvirt_private.syms                           |    2 +-
> >>  src/qemu/qemu_conf.c                               |    2 +-
> >>  .../qemuxml2argv-channel-virtio.xml                |   35 +++
> >>  tests/qemuxml2xmltest.c                            |    1 +
> >>  7 files changed, 320 insertions(+), 50 deletions(-)
> >>  create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-channel-virtio.xml
> >>
> >> diff --git a/docs/schemas/domain.rng b/docs/schemas/domain.rng
> >> index 53b82ce..85df8b8 100644
> >> --- a/docs/schemas/domain.rng
> >> +++ b/docs/schemas/domain.rng
> >> @@ -523,16 +523,36 @@
> >>    </define>
> >>    <define name="controller">
> >>      <element name="controller">
> >> -      <optional>
> >> -        <attribute name="type">
> >> -          <choice>
> >> -            <value>fdc</value>
> >> -            <value>ide</value>
> >> -            <value>scsi</value>
> >> -            <value>sata</value>
> >> -          </choice>
> >> -        </attribute>
> >> -      </optional>
> >> +      <choice>
> >> +        <group>
> >> +          <optional>
> >> +            <attribute name="type">
> >> +              <choice>
> >> +                <value>fdc</value>
> >> +                <value>ide</value>
> >> +                <value>scsi</value>
> >> +                <value>sata</value>
> >> +              </choice>
> >> +            </attribute>
> >> +          </optional>
> >> +        </group>
> >> +        <!-- virtio-serial can have 2 additional attributes -->
> >> +        <group>
> >> +          <attribute name="type">
> >> +            <value>virtio-serial</value>
> >> +          </attribute>
> >> +          <optional>
> >> +            <attribute name="max_ports">
> >> +              <ref name="unsignedInt"/>
> >> +            </attribute>
> >> +          </optional>
> >> +          <optional>
> >> +            <attribute name="vectors">
> >> +              <ref name="unsignedInt"/>
> >> +            </attribute>
> >> +          </optional>
> > 
> > What are these two new attributes doing ?  Can't we just auto-assign
> > those values based on the configured channels later int he XML.
> 
> I'm not 100% sure what vectors does, however I believe this is a
> resource usage tuning knob and therefore can't be inferred. max_ports we
> could possibly default. However, virtio-serial also supports hot-plug,
> although I haven't added libvirt support for it.

Ok that's a good enough reason. Can we just call it 'ports' though.
We don't use '_' in our XML attribute/element naming usually.

> >> @@ -1269,6 +1302,16 @@
> >>        <ref name="driveUnit"/>
> >>      </attribute>
> >>    </define>
> >> +  <define name="virtioserialaddress">
> >> +    <attribute name="controller">
> >> +      <ref name="driveController"/>
> >> +    </attribute>
> >> +    <optional>
> >> +      <attribute name="bus">
> >> +        <ref name="driveBus"/>
> >> +      </attribute>
> >> +    </optional>
> >> +  </define>
> > 
> > What is the "bus" in the content of virtio serial ?
> 
> -device virtserialport,bus=channel0.0...
> 
> I've called 'channel0' the controller, and '0' the bus.
> 
> >> @@ -916,7 +930,8 @@ void virDomainDefClearDeviceAliases(virDomainDefPtr def)
> >>   */
> >>  static int virDomainDeviceInfoFormat(virBufferPtr buf,
> >>                                       virDomainDeviceInfoPtr info,
> >> -                                     int flags)
> >> +                                     int flags,
> >> +                                     const char *indent)
> > 
> > I'm not seeing why we need to pass 'indent' through here? The device info
> > data should always be appearing at exactly the same place in all devices,
> > specifically at  /domain/devices/[device type]/,  so indent level should
> > always be the same.
> 
> I could remove this. I was originally putting <address> elsewhere, which
> screwed up the indentation.

Ok, your original code was definitely wrong then :-P

> 
> >> @@ -1481,10 +1553,49 @@ virDomainControllerDefParseXML(xmlNodePtr node,
> >>      if (virDomainDeviceInfoParseXML(node, &def->info, flags) < 0)
> >>          goto error;
> >>  
> >> +    switch (def->type) {
> >> +    case VIR_DOMAIN_CONTROLLER_TYPE_VIRTIO_SERIAL:
> >> +        0; /* C requires a statement immediately following a label */
> > 
> > Just put a curly brace after the case 
> > 
> >       case VIR_DOMAIN_CONTROLLER_TYPE_VIRTIO_SERIAL: {
> > 
> 
> Will do.
> 
> >> +
> >> +        char *max_ports = virXMLPropString(node, "max_ports");
> >> +        if (max_ports) {
> >> +            int r = virStrToLong_i(max_ports, NULL, 10,
> >> +                                   &def->opts.vioserial.max_ports);
> >> +            if (r != 0 || def->opts.vioserial.max_ports < 0) {
> >> +                virDomainReportError(VIR_ERR_INTERNAL_ERROR,
> >> +                                     _("Invalid max_ports: %s"), max_ports);
> >> +                VIR_FREE(max_ports);
> >> +                goto error;
> >> +            }
> >> +        } else {
> >> +            def->opts.vioserial.max_ports = -1;
> >> +        }
> >> +        VIR_FREE(max_ports);
> >> +
> >> +        char *vectors = virXMLPropString(node, "vectors");
> >> +        if (vectors) {
> >> +            int r = virStrToLong_i(vectors, NULL, 10,
> >> +                                   &def->opts.vioserial.vectors);
> >> +            if (r != 0 || def->opts.vioserial.vectors < 0) {
> >> +                virDomainReportError(VIR_ERR_INTERNAL_ERROR,
> >> +                                     _("Invalid vectors: %s"), vectors);
> >> +                VIR_FREE(vectors);
> >> +                goto error;
> >> +            }
> >> +        } else {
> >> +            def->opts.vioserial.vectors = -1;
> >> +        }
> > 
> > I think  '0' would be preferable as the not-initialized number here,
> > since its not a valid value for either attribute AFAICT
> 
> 0 has a special meaning for vectors. From
> https://fedoraproject.org/wiki/Features/VirtioSerial#How_To_Test:
> 
> If '0' is specified here, MSI will be disabled and a GSI interrupt will
> be used.
> 
> I used a signed int for both values for consistency.

Ok, that makes sense.


Daniel
-- 
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