[PATCH qemu 0/1] MAC address falls to permanent

[PATCH qemu 0/1] MAC address falls to permanent

[Vlao Mao]

A bug was found with the vmxnet3 driver, after changing the MAC address
and rebooting, it falls into the category of a permanent address until
the VM is turned off. Here is log output:

-bash-4.4# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: ens3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group
default qlen 1000
    link/ether 52:54:00:12:34:56 brd ff:ff:ff:ff:ff:ff

-bash-4.4# ip link set dev ens3 address 33:33:33:33:33:33
-bash-4.4# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: ens3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group
default qlen 1000
    link/ether 33:33:33:33:33:33 brd ff:ff:ff:ff:ff:ff
-bash-4.4# ethtool -P ens3
Permanent address: 52:54:00:12:34:56
-bash-4.4# reboot

//rebooting


-bash-4.4# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: ens3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group
default qlen 1000
    link/ether 33:33:33:33:33:33 brd ff:ff:ff:ff:ff:ff
-bash-4.4# ethtool -P ens3
Permanent address: 33:33:33:33:33:33
-bash-4.4#

Vlao Mao (1):
  vmxnet3: add mac address restore upon reset

 hw/net/vmxnet3.c | 2 ++
 1 file changed, 2 insertions(+)

-- 
2.35.1

[PATCH qemu 1/1] vmxnet3: add mac address restore upon reset

[Vlao Mao]

Changing the address with a subsequent reboot makes this address permanent until the vm is turned off

Signed-off-by: Vlao Mao <vlaomao@gmail.com>
---
 hw/net/vmxnet3.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
index 04159c8222..695ca2f923 100644
--- a/hw/net/vmxnet3.c
+++ b/hw/net/vmxnet3.c
@@ -1206,6 +1206,8 @@ static void vmxnet3_reset(VMXNET3State *s)
     s->drv_shmem = 0;
     s->tx_sop = true;
     s->skip_current_tx_pkt = false;
+
+    vmxnet3_reset_mac(s);
 }
 
 static void vmxnet3_update_rx_mode(VMXNET3State *s)
-- 
2.35.1

[PATCH qemu 0/1] MAC address falls to permanent

[Vlao Mao]

A bug was found with the vmxnet3 driver, after changing the MAC address
and rebooting, it falls into the category of a permanent address until
the VM is turned off. Here is log output:

-bash-4.4# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: ens3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group
default qlen 1000
    link/ether 52:54:00:12:34:56 brd ff:ff:ff:ff:ff:ff

-bash-4.4# ip link set dev ens3 address 33:33:33:33:33:33
-bash-4.4# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: ens3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group
default qlen 1000
    link/ether 33:33:33:33:33:33 brd ff:ff:ff:ff:ff:ff
-bash-4.4# ethtool -P ens3
Permanent address: 52:54:00:12:34:56
-bash-4.4# reboot

//rebooting


-bash-4.4# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: ens3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group
default qlen 1000
    link/ether 33:33:33:33:33:33 brd ff:ff:ff:ff:ff:ff
-bash-4.4# ethtool -P ens3
Permanent address: 33:33:33:33:33:33
-bash-4.4#

Vlao Mao (1):
  vmxnet3: add mac address restore upon reset

 hw/net/vmxnet3.c | 2 ++
 1 file changed, 2 insertions(+)

-- 
2.35.1

Re: [PATCH qemu 0/1] MAC address falls to permanent

[Peter Maydell]

On Tue, 31 Jan 2023 at 18:22, Vlao Mao <vlaomao@gmail.com> wrote:
>
> A bug was found with the vmxnet3 driver, after changing the MAC address
> and rebooting, it falls into the category of a permanent address until
> the VM is turned off.

For some network device models (those where the hardware has an
EEPROM and we're modelling "guest programmed a new MAC address
into the EEPROM") that is the correct behaviour. Is the vmxnet3
definitely one of the kind which is not supposed to have a
permanent MAC address backing storage ? (It's paravirtual, so
this would hopefully be indicated in the specs for it.)

thanks
-- PMM

Re: [PATCH qemu 0/1] MAC address falls to permanent

[Влад Мао]

I cannot say for sure, but e1000 does not have this behavior, vmxnet3
in vmware also does not behave this way.
In addition, the address gets there only after a reboot, it does not
get there during normal operation, as you can see from logs i
attached. It seems to me that this is not quite the expected behavior,
isn't it?

вт, 31 янв. 2023 г. в 21:48, Peter Maydell <peter.maydell@linaro.org>:
>
> On Tue, 31 Jan 2023 at 18:22, Vlao Mao <vlaomao@gmail.com> wrote:
> >
> > A bug was found with the vmxnet3 driver, after changing the MAC address
> > and rebooting, it falls into the category of a permanent address until
> > the VM is turned off.
>
> For some network device models (those where the hardware has an
> EEPROM and we're modelling "guest programmed a new MAC address
> into the EEPROM") that is the correct behaviour. Is the vmxnet3
> definitely one of the kind which is not supposed to have a
> permanent MAC address backing storage ? (It's paravirtual, so
> this would hopefully be indicated in the specs for it.)
>
> thanks
> -- PMM

Re: [PATCH qemu 0/1] MAC address falls to permanent

[Laurent Vivier]

CC: maintainers and qemu-devel

Use ./scripts/get_maintainer.pl to have the list of the maintainers.

Always send your patches to qemu-devel&nongnu.org

Thanks,
Laurent

Le 30/01/2023 à 18:54, ~vlaomao a écrit :
> A bug was found with the vmxnet3 driver, after changing the MAC address
> and rebooting, it falls into the category of a permanent address until
> the VM is turned off. Here is log output:
> 
> -bash-4.4# ip a
> 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
> group default qlen 1
>      link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
>      inet 127.0.0.1/8 scope host lo
>         valid_lft forever preferred_lft forever
> 2: ens3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group
> default qlen 1000
>      link/ether 52:54:00:12:34:56 brd ff:ff:ff:ff:ff:ff
> 
> -bash-4.4# ip link set dev ens3 address 33:33:33:33:33:33
> -bash-4.4# ip a
> 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
> group default qlen 1
>      link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
>      inet 127.0.0.1/8 scope host lo
>         valid_lft forever preferred_lft forever
> 2: ens3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group
> default qlen 1000
>      link/ether 33:33:33:33:33:33 brd ff:ff:ff:ff:ff:ff
> -bash-4.4# ethtool -P ens3
> Permanent address: 52:54:00:12:34:56
> -bash-4.4# reboot
> 
> //rebooting
> 
> 
> -bash-4.4# ip a
> 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
> group default qlen 1
>      link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
>      inet 127.0.0.1/8 scope host lo
>         valid_lft forever preferred_lft forever
> 2: ens3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group
> default qlen 1000
>      link/ether 33:33:33:33:33:33 brd ff:ff:ff:ff:ff:ff
> -bash-4.4# ethtool -P ens3
> Permanent address: 33:33:33:33:33:33
> -bash-4.4#
> 
> VlaoMao (1):
>    vmxnet3: add mac address restore upon reset
> 
>   hw/net/vmxnet3.c | 2 ++
>   1 file changed, 2 insertions(+)
>