"Michael S. Tsirkin" <m...@redhat.com> writes:
> On Thu, Feb 25, 2010 at 11:10:15AM +0100, Markus Armbruster wrote:
>> Guest device and host netdev are peers, i.e. it's a 1:1 relation.
>> However, we fail to enforce that:
>>
>> $ qemu -nodefaults --nographic -netdev user,id=net0 -device
>> e1000,netdev=net0 -device virtio-net-pci,netdev=net0 -monitor stdio
>> QEMU 0.12.50 monitor - type 'help' for more information
>> (qemu) info network
>> Devices not on any VLAN:
>> net0: net=10.0.2.0, restricted=n peer=virtio-net-pci.0
>> e1000.0: model=e1000,macaddr=52:54:00:12:34:56 peer=net0
>> virtio-net-pci.0: model=virtio-net-pci,macaddr=52:54:00:12:34:57
>> peer=net0
>>
>> It's all downhill from there.
>>
>> Signed-off-by: Markus Armbruster <arm...@redhat.com>
>> ---
>> hw/qdev-properties.c | 3 +++
>> net.c | 1 +
>> 2 files changed, 4 insertions(+), 0 deletions(-)
>>
>> diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
>> index 277ff9e..89efd91 100644
>> --- a/hw/qdev-properties.c
>> +++ b/hw/qdev-properties.c
>> @@ -341,6 +341,9 @@ static int parse_netdev(DeviceState *dev, Property
>> *prop, const char *str)
>> *ptr = qemu_find_netdev(str);
>> if (*ptr == NULL)
>> return -1;
>> + if ((*ptr)->peer) {
>> + return -1;
>> + }
>
> Not even -EBUSY?
> Can this produce a helpful diagnostic message?
Callers take care of that. It's how property parse methods work.
In this case:
property "virtio-net-pci.netdev": failed to parse "net0"
can't set property "netdev" to "net0" for "virtio-net-pci"
>> return 0;
>> }
>>
>> diff --git a/net.c b/net.c
>> index a1bf49f..e6c96d3 100644
>> --- a/net.c
>> +++ b/net.c
>> @@ -245,6 +245,7 @@ VLANClientState *qemu_new_net_client(NetClientInfo *info,
>> QTAILQ_INSERT_TAIL(&vc->vlan->clients, vc, next);
>> } else {
>> if (peer) {
>> + assert(!peer->peer);
>
> Do we ever get herE?
If "get here" means "conditional entered": yes. For instance, with the
command line from the commit message, we get here for each of the
-device, like this:
#0 qemu_new_net_client (info=0x8b2ce0, vlan=0x0, peer=0xcd83f0,
model=0x5ea826 "e1000", name=0x0) at /work/armbru/qemu/net.c:227
#1 0x000000000047682f in qemu_new_nic (info=0x8b2ce0, conf=0x7fffece4a270,
model=0x5ea826 "e1000", name=0x0, opaque=0x7fffece4a010)
at /work/armbru/qemu/net.c:273
#2 0x0000000000447c74 in pci_e1000_init (pci_dev=0x7fffece4a010)
at /work/armbru/qemu/hw/e1000.c:1125
#3 0x0000000000422335 in pci_qdev_init (qdev=0x7fffece4a010, base=0x8b2dc0)
at /work/armbru/qemu/hw/pci.c:1647
#4 0x00000000004bbb29 in qdev_init (dev=0x7fffece4a010)
at /work/armbru/qemu/hw/qdev.c:265
If "get here" means "assertion fails": only if somebody breaks something
elsewhere. And then assertion will slap his wrist.
>> vc->peer = peer;
>> peer->peer = vc;
>> }
>> --
>> 1.6.6
>>
>>
