[libvirt] [RESEND][PATCH v2] qemu allow persistent modifications of NICs

Hu Tao hutao at cn.fujitsu.com
Tue May 24 01:48:40 UTC 2011


On Mon, May 23, 2011 at 11:09:21AM +0900, KAMEZAWA Hiroyuki wrote:
> 
> Slightly updated against the latest git tree. but didn't update version number.
> ==
> Now, only attach/detatch/update for disks are supporeted for inactive
> domains.
> This patch allows to modify network interfaces of inactive domains.
> Users can modify inactive domains with --persistent flag.
> 
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> 
> * src/conf/domain_conf.c:
> (virDomainNetInsert)     : Insert a network device to domain definition.
> (virDomainNetIndexByMac) : Returns an index of net device in array.
> (virDomainNetRemoveByMac): Remove a NIC of passed MAC address.
> 
> * src/qemu/qemu_driver.c
> (qemuDomainAttachDeviceConfig): add codes for NIC.
> (qemuDomainDetachDeviceConfig): add codes for NIC.
> 
> Changelog v1->v2:
>   - fixed virDomainNetInsert
>   - removed target name check. (It seems I misunderstood something.)
>   - fixed error check in qemuDomainAttachDeviceConfig
>   - fixed error message in qemuDomainDetachDeviceConfig
> ---
>  src/conf/domain_conf.c   |   45 +++++++++++++++++++++++++++++++++++++++++++++
>  src/conf/domain_conf.h   |    4 ++++
>  src/libvirt_private.syms |    3 +++
>  src/qemu/qemu_driver.c   |   31 +++++++++++++++++++++++++++++++
>  4 files changed, 83 insertions(+), 0 deletions(-)
> 
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 6129bbc..d85c8bc 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -5177,6 +5177,51 @@ int virDomainDiskRemoveByName(virDomainDefPtr def, const char *name)
>      return 0;
>  }
>  
> +int virDomainNetInsert(virDomainDefPtr def, virDomainNetDefPtr net)
> +{
> +    if (VIR_REALLOC_N(def->nets, def->nnets + 1) < 0)
> +        return -1;
> +    def->nets[def->nnets]  = net;
> +    def->nnets++;
> +    return 0;
> +}
> +
> +int virDomainNetIndexByMac(virDomainDefPtr def, const unsigned char *mac)
> +{
> +    int i;
> +
> +    for (i = 0; i < def->nnets; i++)
> +        if (!memcmp(def->nets[i]->mac, mac, VIR_MAC_BUFLEN))
> +            return i;
> +    return -1;
> +}
> +
> +static void virDomainNetRemove(virDomainDefPtr def, size_t i)
> +{

If i exceeds def->nnets, you may access beyond def->nets, which may
corrupt memory.

> +    if (def->nnets > 1) {
> +        memmove(def->nets + i,
> +                def->nets + i + 1,
> +                sizeof(*def->nets) * (def->nnets - (i + 1)));
> +        def->nnets--;
> +        if (VIR_REALLOC_N(def->nets, def->nnets) < 0) {
> +            /* ignore harmless */
> +        }

ignore_value() is provided to ignore a return value.

> +    } else {
> +        VIR_FREE(def->nets);
> +        def->nnets = 0;
> +    }
> +}
> +
> +int virDomainNetRemoveByMac(virDomainDefPtr def, const unsigned char *mac)
> +{
> +    int i = virDomainNetIndexByMac(def, mac);
> +
> +    if (i < 0)
> +        return -1;
> +    virDomainNetRemove(def, i);
> +    return 0;
> +}
> +
>  
>  int virDomainControllerInsert(virDomainDefPtr def,
>                                virDomainControllerDefPtr controller)
> diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
> index 5fe31d4..f195caa 100644
> --- a/src/conf/domain_conf.h
> +++ b/src/conf/domain_conf.h
> @@ -1360,6 +1360,10 @@ int virDomainDiskDefAssignAddress(virCapsPtr caps, virDomainDiskDefPtr def);
>  void virDomainDiskRemove(virDomainDefPtr def, size_t i);
>  int virDomainDiskRemoveByName(virDomainDefPtr def, const char *name);
>  
> +int virDomainNetIndexByMac(virDomainDefPtr def, const unsigned char *mac);
> +int virDomainNetInsert(virDomainDefPtr def, virDomainNetDefPtr net);

Will it be better to add virDomainNetRemove here as a counterpart of
virDomainNetInsert? Although no external file uses it.

> +int virDomainNetRemoveByMac(virDomainDefPtr def, const unsigned char *mac);
> +
>  int virDomainControllerInsert(virDomainDefPtr def,
>                                virDomainControllerDefPtr controller);
>  void virDomainControllerInsertPreAlloced(virDomainDefPtr def,
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 7b6151c..eb55025 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -290,6 +290,9 @@ virDomainLoadAllConfigs;
>  virDomainMemballoonModelTypeFromString;
>  virDomainMemballoonModelTypeToString;
>  virDomainNetDefFree;
> +virDomainNetIndexByMac;
> +virDomainNetInsert;
> +virDomainNetRemoveByMac;
>  virDomainNetTypeToString;
>  virDomainObjAssignDef;
>  virDomainObjCopyPersistentDef;
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index 691965d..ef2c5f0 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -4245,6 +4245,7 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef,
>                               virDomainDeviceDefPtr dev)
>  {
>      virDomainDiskDefPtr disk;
> +    virDomainNetDefPtr net;
>  
>      switch (dev->type) {
>      case VIR_DOMAIN_DEVICE_DISK:
> @@ -4267,6 +4268,24 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef,
>              return -1;
>          break;
>  
> +    case VIR_DOMAIN_DEVICE_NET:
> +        net = dev->data.net;
> +        if (virDomainNetIndexByMac(vmdef, net->mac) >= 0) {
> +            char macbuf[VIR_MAC_STRING_BUFLEN];
> +
> +            virFormatMacAddr(net->mac, macbuf);
> +            qemuReportError(VIR_ERR_INVALID_ARG,
> +                            _("mac %s already exists"), macbuf);
> +            return -1;
> +        }
> +        if (virDomainNetInsert(vmdef, net)) {
> +            virReportOOMError();
> +            return -1;
> +        }
> +        dev->data.net = NULL;
> +        if (qemuDomainAssignPCIAddresses(vmdef) < 0)
> +            return -1;
> +        break;
>      default:
>           qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>                           _("persistent attach of device is not supported"));
> @@ -4281,6 +4300,7 @@ qemuDomainDetachDeviceConfig(virDomainDefPtr vmdef,
>                               virDomainDeviceDefPtr dev)
>  {
>      virDomainDiskDefPtr disk;
> +    virDomainNetDefPtr net;
>  
>      switch (dev->type) {
>      case VIR_DOMAIN_DEVICE_DISK:
> @@ -4291,6 +4311,17 @@ qemuDomainDetachDeviceConfig(virDomainDefPtr vmdef,
>              return -1;
>          }
>          break;
> +    case VIR_DOMAIN_DEVICE_NET:
> +        net = dev->data.net;
> +        if (virDomainNetRemoveByMac(vmdef, net->mac)) {
> +            char macbuf[VIR_MAC_STRING_BUFLEN];
> +
> +            virFormatMacAddr(net->mac, macbuf);
> +            qemuReportError(VIR_ERR_INVALID_ARG,
> +                            _("mac %s doesn't exist."), macbuf);
> +            return -1;
> +        }
> +        break;
>      default:
>          qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>                          _("persistent detach of device is not supported"));
> -- 
> 1.7.4.1




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