[libvirt] [Patch v7 1/4] libvirt/qemu - persistent modification of domain.
Wen Congyang
wency at cn.fujitsu.com
Tue Mar 29 05:17:55 UTC 2011
At 03/29/2011 12:32 PM, KAMEZAWA Hiroyuki Write:
> 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 ?
No.
In patch 2, the function qemuDomainDeviceAddressFixup() may modify vmdef
and return -1:
=============
+static int qemuDomainDeviceAddressFixup(virDomainDefPtr vmdef, bool pci)
+{
+ if (!pci && virDomainDefAddImplicitControllers(vmdef))
+ return -1;
+ /* added controller requires PCI address */
+ return qemuDomainAssignPCIAddresses(vmdef);
+}
+
=============
The function virDomainDefAddImplicitControllers() may modify vmdef. If
qemuDomainAssignPCIAddresses() failed, there is no way to rollback the
operation that virDomainDefAddImplicitControllers() do.
>
>
>
>>> +
>>> + 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
>
>
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