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Re: [PATCH v3] arm/aspeed: Rework NIC attachment
From: |
Markus Armbruster |
Subject: |
Re: [PATCH v3] arm/aspeed: Rework NIC attachment |
Date: |
Thu, 28 May 2020 09:12:06 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) |
Cédric Le Goater <clg@kaod.org> writes:
> On 5/27/20 3:36 PM, Markus Armbruster wrote:
>> Cédric Le Goater <clg@kaod.org> writes:
>>
>>> The number of MACs supported by an Aspeed SoC is defined by "macs_num"
>>> under the SoC model, that is two for the AST2400 and AST2500 and four
>>> for the AST2600. The model initializes the maximum number of supported
>>> MACs but the number of realized devices is capped by the number of
>>> network device back-ends defined on the command line. This can leave
>>> unrealized devices hanging around in the QOM composition tree.
>>>
>>> Modify the machine initialization to define which MACs are attached to
>>> a network device back-end using a bit-field property "macs-mask" and
>>> let the SoC realize all network devices.
>>>
>>> The default setting of "macs-mask" is "use MAC0" only, which works for
>>> all our AST2400 and AST2500 machines. The AST2600 machines have
>>> different configurations. The AST2600 EVB machine activates MAC1, MAC2
>>> and MAC3 and the Tacoma BMC machine activates MAC2.
>>
>> Let's be more clear on what this means, and "This is actually a device
>> modelling fix for these two machines." Okay?
>
> Well, I guess so. It's a fix in the way we attach network backends to
> the MACs of the machines.
Yes, it's that too.
> On the tacoma-bmc, we had to use '-nic <foo> -nic <bar> -nic <good one>'
> to configure the MAC2 in use by the machine. Which was dubious.
I think you had to use something like
-nic none -nic none -nic GOOD-ONE -nic none
to get virtual hardware that matches the physical hardware, which I
understand has all four MACs on the die, but only MAC2 connected to the
outside.
In particular, the default configuration (no -nic, -nodefaults, etc.)
got you only MAC0. With just -nodefaults, you got none at all.
> Now, a single -nic is enough.
Now you get all four MACs regardless of configuration, but only MAC2 can
be connected to a backend, e.g. with a single -nic.
The default configuration (no -nic, -nodefaults, etc.) just works: MAC2
connected to the default network backend.
With just -nodefaults, MAC2 remains unconnected.
This matches how other machines work.
>>> Inactive MACs will have no peer and QEMU may warn the user with :
>>>
>>> qemu-system-arm: warning: nic ftgmac100.0 has no peer
>>> qemu-system-arm: warning: nic ftgmac100.1 has no peer
>>> qemu-system-arm: warning: nic ftgmac100.3 has no peer
>>>
>>> Signed-off-by: Cédric Le Goater <clg@kaod.org>
>>> Reviewed-by: Markus Armbruster <armbru@redhat.com>
>>
>> Here's the "info qom-tree" change for tacoma-bmc:
>>
>> /machine (tacoma-bmc-machine)
>> /peripheral (container)
>> /peripheral-anon (container)
>> /soc (ast2600-a1)
>> [...]
>> /ftgmac100[0] (ftgmac100)
>> /ftgmac100[0] (qemu:memory-region)
>> /ftgmac100[1] (ftgmac100)
>> + /ftgmac100[0] (qemu:memory-region)
>> /ftgmac100[2] (ftgmac100)
>> + /ftgmac100[0] (qemu:memory-region)
>> /ftgmac100[3] (ftgmac100)
>> + /ftgmac100[0] (qemu:memory-region)
>
> Yes. All are realized now.
>
>> [...]
>> /mii[0] (aspeed-mmi)
>> /aspeed-mmi[0] (qemu:memory-region)
>> /mii[1] (aspeed-mmi)
>> + /aspeed-mmi[0] (qemu:memory-region)
>> /mii[2] (aspeed-mmi)
>> + /aspeed-mmi[0] (qemu:memory-region)
>> /mii[3] (aspeed-mmi)
>> + /aspeed-mmi[0] (qemu:memory-region)
>
> Same for the MMI interfaces on AST2600.
>
>> These changes are due to realizing MAC1, MAC2, MAC3. Looks good.
>>
>> Here's "info qtree":
>>
>> dev: ftgmac100, id ""
>> gpio-out "sysbus-irq" 1
>> aspeed = true
>> - mac = "52:54:00:12:34:56"
>> - netdev = "hub0port0"
>> + mac = "52:54:00:12:34:57"
>> + netdev = ""
>> mmio 000000001e660000/0000000000002000
>> dev: ftgmac100, id ""
>> - aspeed = false
>> - mac = "00:00:00:00:00:00"
>> + gpio-out "sysbus-irq" 1
>> + aspeed = true
>> + mac = "52:54:00:12:34:58"
>> netdev = ""
>> + mmio 000000001e680000/0000000000002000
>> dev: ftgmac100, id ""
>> - aspeed = false
>> - mac = "00:00:00:00:00:00"
>> - netdev = ""
>> + gpio-out "sysbus-irq" 1
>> + aspeed = true
>> + mac = "52:54:00:12:34:56"
>> + netdev = "hub0port0"
>> + mmio 000000001e670000/0000000000002000
>> dev: ftgmac100, id ""
>> - aspeed = false
>> - mac = "00:00:00:00:00:00"
>> + gpio-out "sysbus-irq" 1
>> + aspeed = true
>> + mac = "52:54:00:12:34:59"
>> netdev = ""
>> + mmio 000000001e690000/0000000000002000
>> [...]
>> dev: aspeed-mmi, id ""
>> mmio 000000001e650000/0000000000000008
>> dev: aspeed-mmi, id ""
>> + mmio 000000001e650008/0000000000000008
>> dev: aspeed-mmi, id ""
>> + mmio 000000001e650010/0000000000000008
>> dev: aspeed-mmi, id ""
>> + mmio 000000001e650018/0000000000000008
>>
>> Here we can see the network backend now gets connected to MAC2 instead
>> of MAC0.
>
> yes.
>
> With only one nic on the command line, the backend was attached to the
> first (unused) MAC0 of the machine and now it is attached to the first
> active MAC2 of the machine.
>
>>
>> This is without any networking-related options, i.e. we get just the
>> single default network backend.
>>
>>> ---
>>>
>>> To be applied on top of patch :
>>>
>>> "arm/aspeed: Compute the number of CPUs from the SoC definition"
>>>
>>> 20200519091631.1006073-1-clg@kaod.org/">http://patchwork.ozlabs.org/project/qemu-devel/patch/20200519091631.1006073-1-clg@kaod.org/
>>>
>>> Markus, do you mind taking this patch in your QOM series also ?
>>
>> On the contrary!
>>
>> I'll work my "info qom-tree" and "info qtree" diffs into the commit
>> message, if you don't mind.
>
> Sure.
Today, I hope. Thanks!