[libvirt] [PATCH 3/5] libvirt/qemu - support persistent modification of devices.
KAMEZAWA Hiroyuki
kamezawa.hiroyu at jp.fujitsu.com
Wed Mar 16 00:44:36 UTC 2011
On Tue, 15 Mar 2011 15:55:51 -0600
Eric Blake <eblake at redhat.com> wrote:
> On 03/02/2011 06:11 PM, KAMEZAWA Hiroyuki wrote:
> >>From f7a997e3cd58cfac81e131afdd20c3691267831d Mon Sep 17 00:00:00 2001
> > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> > Date: Thu, 3 Mar 2011 09:43:07 +0900
> > Subject: [PATCH 3/5] libivrt/qemu - support persistent modification of devices.
> >
> > Now, virsh attach-***/detach-*** has --persistent option and
> > it can update XML definition of inactive domains.
>
> Hmm, looking at the recent additions of other virsh persistent support,
> the single --persistent flag of virsh attach-{device,disk,interface} are
> a bit limited; --persistent means the same thing as --config, but we may
> need to add a counterpart --live option that specifies live only. But
> cleaning up virsh to better expose the underlying flags is a separate
> patch; this patch only deals with implementing the flags internally.
>
yes.
> > Now, disk and nic are supported in Xen, but none in qemu.
>
> It would be nice to get all devices supported, but incremental is better
> than nothing at all.
>
> >
> > This patch adds a function for permanent modification for qemu.
> > Following patches will add disk/network suport.
> >
> > TODO:
> > - finally, need to do hotplug + XML modification for active domain.
> >
> > Changelog v3->v4
> > - fixed trailing white spaces.
> > - splitted into 2 part and this patch only contains wrappers.
> > Changelog v2->v3:
> > - clean ups.
> > - handle all VIR_DOMAIN_DEVICE_MODIFY_XXX flags.
> > ---
> > src/qemu/qemu_driver.c | 143 ++++++++++++++++++++++++++++++++++++++++++++----
> > 1 files changed, 131 insertions(+), 12 deletions(-)
> >
> > diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> > index c9095bb..3248cdc 100644
> > --- a/src/qemu/qemu_driver.c
> > +++ b/src/qemu/qemu_driver.c
> > @@ -4099,16 +4099,131 @@ cleanup:
> > return ret;
> > }
> >
> > -static int qemudDomainAttachDeviceFlags(virDomainPtr dom,
> > +/*
> > + * 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)
> > +{
> > +
> > + /* At first, check device confliction */
>
> s/device confliction/for device support/
>
will fix.
> > + switch(newdev->type) {
> > + default:
> > + qemuReportError(VIR_ERR_INVALID_ARG, "%s",
> > + _("Sorry, the device is not suppored for now"));
>
> s/suppored/supported/ (twice)
>
will fix. ....I'll use spell checker.
> > +
> > +static int qemuDomainModifyDevicePersistent(virDomainPtr dom,
> > const char *xml,
>
> Indentation is not consistent.
>
ok.
> > - unsigned int flags) {
> > - if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG) {
> > - qemuReportError(VIR_ERR_OPERATION_INVALID,
> > - "%s", _("cannot modify the persistent configuration of a domain"));
> > + unsigned int attach, int flags)
> > +{
> > + struct qemud_driver *driver;
> > + virDomainDeviceDefPtr device;
> > + virDomainDefPtr vmdef;
> > + virDomainObjPtr vm;
> > + int ret = -1;
> > +
> > + if (!dom || !dom->conn || !dom->name || !xml) {
> > + qemuReportError(VIR_ERR_INTERNAL_ERROR,
> > + _("internal error : %s"), __FUNCTION__);
> > + return -1;
> > + }
> > + /*
> > + * When both of MODIFY_CONFIG and MODIFY_LIVE is specified at the same time,
> > + * return error for now. We should support this later.
> > + */
> > + if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE) {
> > + qemuReportError(VIR_ERR_INVALID_ARG, "%s",
> > + _("Now, cannot modify alive domain and its definition "
> > + "at the same time."));
>
> It shouldn't be too hard to attempt supporting this now - after all, we
> already did just that with Taku Izumi's patch for virsh setmem.
> qemudDomainSetMemoryFlags can be a good reference point for how to
> implement a command that first validates all conditions required by the
> flags, then modifies the live configuration if requested and still live,
> then modifies the persistent configuration if requested.
>
Can we do it in atomic ?
> I think there have been enough findings already (Wen's feedback has also
> been useful), as well as quite a bit of upstream churn that will require
> rebasing aspects of your patch, that I'll wait for v5 of this series; if
> you use 'git send-email --subject-prefix=PATCHv5', that will make it
> easier to recognize from the subject line that it is a resend.
>
ok, will do.
Thanks,
-Kame
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