[libvirt] [Patch v7 1/4] libvirt/qemu - persistent modification of domain.

[KAMEZAWA Hiroyuki]

On Tue, 29 Mar 2011 11:24:23 +0800
Wen Congyang <wency at cn.fujitsu.com> wrote:

> At 03/25/2011 04:10 PM, KAMEZAWA Hiroyuki Write:
> > This is v7. Dropped patches for Nics and added 2 sanity checks and
> > show correct error messages.
> > 
> > =
> >>From 948597237bd9ecfc5c7343fd30efdca37733274e Mon Sep 17 00:00:00 2001
> > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> > Date: Fri, 25 Mar 2011 16:59:55 +0900
> > Subject: [PATCHv7 1/4] libvirt/qemu - persistent modification of devices.
> > 
> > Now, qemudDomainAttachDeviceFlags() and qemudDomainDetachDeviceFlags()
> > doesn't support VIR_DOMAIN_DEVICE_MODIFY_CONFIG. By this, virsh's
> > at(de)tatch-device --persistent cannot modify qemu config.
> > (Xen allows it.)
> > 
> > This patch is a base patch for adding support of devices in
> > step by step manner. Following patches will add some device
> > support.
> > 
> > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> > ---
> >  src/qemu/qemu_driver.c |  138 +++++++++++++++++++++++++++++++++++++++++++-----
> >  1 files changed, 125 insertions(+), 13 deletions(-)
> > 
> > diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> > index af897ad..a4fb1cd 100644
> > --- a/src/qemu/qemu_driver.c
> > +++ b/src/qemu/qemu_driver.c
> > @@ -4144,16 +4144,125 @@ cleanup:
> >      return ret;
> >  }
> >  
> > -static int qemudDomainAttachDeviceFlags(virDomainPtr dom,
> > -                                        const char *xml,
> > -                                        unsigned int flags) {
> > -    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG) {
> > -        qemuReportError(VIR_ERR_OPERATION_INVALID,
> > -                        "%s", _("cannot modify the persistent configuration of a domain"));
> > +/*
> > + * Attach a device given by XML, the change will be persistent
> > + * and domain XML definition file is updated.
> > + */
> > +static int qemuDomainAttachDevicePersistent(virDomainDefPtr vmdef,
> > +                                            virDomainDeviceDefPtr newdev)
> > +{
> > +
> > +    switch(newdev->type) {
> > +    default:
> > +        qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> > +                        _("Sorry, the device is not supported for now"));
> > +        return -1;
> > +    }
> > +
> > +    return 0;
> > +}
> > +
> > +static int qemuDomainDetachDevicePersistent(virDomainDefPtr vmdef,
> > +                                            virDomainDeviceDefPtr device)
> > +{
> > +    switch(device->type) {
> > +    default:
> > +        qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> > +                        _("Sorry, the device is not supported for now"));
> >          return -1;
> >      }
> > +    return 0;
> > +}
> > +
> > +static int qemuDomainModifyDevicePersistent(virDomainPtr dom,
> > +                                            const char *xml,
> > +                                            unsigned int attach,
> > +                                            unsigned int flags)
> > +{
> > +    struct qemud_driver *driver;
> > +    virDomainDeviceDefPtr device;
> > +    virDomainDefPtr vmdef;
> > +    virDomainObjPtr vm;
> > +    int ret = -1;
> > +
> > +    /*
> > +     * When both of MODIFY_CONFIG and MODIFY_LIVE is specified at the same,
> > +     * time return error for now. We should support this later.
> 
> s/at the same, time/at the same time,/
> 
will fix.


> > +     */
> > +    if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE) {
> > +        qemuReportError(VIR_ERR_OPERATION_INVALID, "%s",
> > +                        _("Now, cannot modify alive domain and its definition "
> 
> You use 'alive domain' here, but you use 'active domain' below.
> The message should be consistent.
> 

will fix.


> > +                          "at the same time."));
> > +        return -1;
> > +    }
> > +
> > +    driver = dom->conn->privateData;
> > +    qemuDriverLock(driver);
> > +    vm = virDomainFindByName(&driver->domains, dom->name);
> > +    if (!vm) {
> > +        qemuReportError(VIR_ERR_NO_DOMAIN, _("no domain with name : '%s'"),
> > +                        dom->name);
> > +        goto unlock_out;
> > +    }
> > +
> > +    if (qemuDomainObjBeginJobWithDriver(driver, vm) < 0)
> > +        goto unlock_out;
> > +
> > +    if (virDomainObjIsActive(vm)) {
> > +        /*
> > +         * For now, just allow updating inactive domains. Further development
> > +         * will allow updating both active domain and its config file at
> > +         * the same time.
> > +         */
> > +        qemuReportError(VIR_ERR_OPERATION_INVALID, "%s",
> > +                        _("unsupported to update active domain's definition."));
> > +        goto endjob;
> > +    }
> > +
> > +    vmdef = virDomainObjGetPersistentDef(driver->caps, vm);
> >  
> > -    return qemudDomainAttachDevice(dom, xml);
> > +    if (!vmdef)
> > +        goto endjob;
> > +
> > +    device = virDomainDeviceDefParse(driver->caps,
> > +                                     vmdef, xml, VIR_DOMAIN_XML_INACTIVE);
> > +    if (!device)
> > +        goto endjob;
> > +
> > +    if (attach)
> > +        ret = qemuDomainAttachDevicePersistent(vmdef, device);
> > +    else
> > +        ret = qemuDomainDetachDevicePersistent(vmdef, device);
> > +
> > +    if (!ret) /* save the result */
> > +        ret = virDomainSaveConfig(driver->configDir, vmdef);
> 
> vmdef may be modified even if ret is not 0, but you do not update
> the xml file. I do not find any problem about this, but it may be
> better to update the xml file when ret is not 0.
> 

Hmm ? I'll add a spec. on qemuDomainAt(De)tachDevicePersistent() to
never update vmdef when return !0. Is it ok ?



> > +
> > +    virDomainDeviceDefFree(device);
> > +
> > +endjob:
> > +    if (qemuDomainObjEndJob(vm) == 0)
> > +        vm = NULL;
> > +unlock_out:
> > +    if (vm)
> > +        virDomainObjUnlock(vm);
> > +    qemuDriverUnlock(driver);
> > +    return ret;
> > +}
> > +
> > +static int qemudDomainAttachDeviceFlags(virDomainPtr dom,
> > +                                        const char *xml,
> > +                                        unsigned int flags)
> > +{
> > +    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG)
> > +        return qemuDomainModifyDevicePersistent(dom, xml, 1, flags);
> > +
> > +    if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE)
> > +        return qemudDomainAttachDevice(dom, xml);
> > +
> > +    qemuReportError(VIR_ERR_INVALID_ARG,
> > +                    _("bad flag: %x not supported"), flags);
> 
> If the flags is VIR_DOMAIN_DEVICE_MODIFY_LIVE | unsupported_flags, we do not
> report error here.
> 
> You can use the macro virCheckFlags to check it.
> 

Hm, ok. will see it.

Thanks,
-Kame