[libvirt] [PATCHv7 3/4] libvirt/qemu - check address confliction before addition.

[KAMEZAWA Hiroyuki]

On Tue, 29 Mar 2011 10:41:57 +0800
Hu Tao <hutao at cn.fujitsu.com> wrote:

> On Fri, Mar 25, 2011 at 05:17:03PM +0900, KAMEZAWA Hiroyuki wrote:
> > >From 638341bdf3eaac824e36d265e134608279750049 Mon Sep 17 00:00:00 2001
> > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> > Date: Fri, 25 Mar 2011 17:10:58 +0900
> > Subject: [PATCHv7 3/4] libvirt/qemu - check address confliction before addition.
> > 
> > qemuDomainAttachDevicePersistent() calls qemuDomainAssignPCIAddresses()
> > and virDomainDefAddImplicitControllers() at the end of its call.
> > 
> > But PCI/Drive address confliction checks are
> >  PCI - confliction will be found but error report is not verbose.
> >  Drive - never done.
> > 
> > For example, you can add following (unusual) 2 devices without errors.
> > 
> > <disk type='file' device='disk'>
> >    <driver name='qemu' type='raw'/>
> >    <source file='/var/lib/libvirt/images/test3.img'/>
> >    <target dev="sdx" bus='scsi'/>
> >    <address type='drive' controller='0' bus='0' unit='0'/>
> > </disk>
> > 
> > <disk type='file' device='disk'>
> >    <driver name='qemu' type='raw'/>
> >    <source file='/var/lib/libvirt/images/test3.img'/>
> >    <target dev="sdy" bus='scsi'/>
> >    <address type='drive' controller='0' bus='0' unit='0'/>
> > </disk>
> > 
> > It's better to check drive address confliction before addition.
> > 
> > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> > ---
> >  src/conf/domain_conf.c   |   59 ++++++++++++++++++++++++++++++++++++++++++++++
> >  src/conf/domain_conf.h   |    2 +
> >  src/libvirt_private.syms |    1 +
> >  src/qemu/qemu_driver.c   |    9 +++++++
> >  4 files changed, 71 insertions(+), 0 deletions(-)
> > 
> > diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> > index 3e3f342..4a54f62 100644
> > --- a/src/conf/domain_conf.c
> > +++ b/src/conf/domain_conf.c
> > @@ -1287,6 +1287,65 @@ void virDomainDefClearDeviceAliases(virDomainDefPtr def)
> >      virDomainDeviceInfoIterate(def, virDomainDeviceInfoClearAlias, NULL);
> >  }
> >  
> > +static int virDomainDeviceAddressMatch(virDomainDefPtr def ATTRIBUTE_UNUSED,
> > +                                       virDomainDeviceInfoPtr info,
> > +                                       void *opaque)
> > +{
> > +    virDomainDeviceInfoPtr checked = opaque;
> > +    /* skip to check confliction of alias */
> > +    if (info->type != checked->type)
> > +            return 0;
> > +    if (info->alias && checked->alias && strcmp(info->alias, checked->alias))
> 
> !STREQ instead of strcmp
> 

ok.


> > +            return -1;
> > +    if (!memcmp(&info->addr, &checked->addr, sizeof(info->addr)))
> 
> Is it safe to memcmp an union like this? In the cases members of an
> union are of different sizes, and we intent to memcmp an union member
> that has a smaller size than the other members, then data in space
> not used by the union member to be compared is also compared. This is
> not a desired result.

As far as I checked, it's zero cleared at allocation. Hmm, making this function
bigger ?

Thanks,
-Kame