Re: [PATCH v5 11/16] hw/microblaze: Support various endianness for s3adsp1800 machines

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 6/2/25 14:20, Daniel P. Berrangé wrote:
> On Thu, Feb 06, 2025 at 02:10:47PM +0100, Philippe Mathieu-Daudé wrote:
>> Introduce an abstract machine parent class which defines
>> the 'little_endian' property. Duplicate the current machine,
>> which endian is tied to the binary endianness, to one big
>> endian and a little endian machine; updating the machine
>> description. Keep the current default machine for each binary.
>>
>> 'petalogix-s3adsp1800' machine is aliased as:
>> - 'petalogix-s3adsp1800-be' on big-endian binary,
>> - 'petalogix-s3adsp1800-le' on little-endian one.
> 
> Does it makes sense to expose these as different machine types ?
> 
> If all the HW is identical in both cases, it feels like the
> endianness could just be a bool property of the machine type,
> rather than a new machine type.

To clarify what we are trying to achieve here:

1/ Current situation:

$ qemu-system-microblaze -M help
Supported machines are:
none                 empty machine
petalogix-ml605      PetaLogix linux refdesign for xilinx ml605 (big 
endian) (deprecated)
petalogix-s3adsp1800 PetaLogix linux refdesign for xilinx Spartan 
3ADSP1800 (default)
xlnx-zynqmp-pmu      Xilinx ZynqMP PMU machine (big endian) (deprecated)
$ qemu-system-microblazeel -M help
Supported machines are:
none                 empty machine
petalogix-ml605      PetaLogix linux refdesign for xilinx ml605 (little 
endian)
petalogix-s3adsp1800 PetaLogix linux refdesign for xilinx Spartan 
3ADSP1800 (default)
xlnx-zynqmp-pmu      Xilinx ZynqMP PMU machine (little endian)

1 architecture declined in 2 binaries, total of 6 machines

2/ With this series:

qemu-system-microblaze -M help
Supported machines are:
none                 empty machine
petalogix-ml605      PetaLogix linux refdesign for xilinx ml605 (big 
endian) (deprecated)
petalogix-s3adsp1800 PetaLogix linux refdesign for xilinx Spartan 
3ADSP1800 (big endian) (alias of petalogix-s3adsp1800-be)
petalogix-s3adsp1800-be PetaLogix linux refdesign for xilinx Spartan 
3ADSP1800 (big endian) (default)
petalogix-s3adsp1800-le PetaLogix linux refdesign for xilinx Spartan 
3ADSP1800 (little endian)
xlnx-zynqmp-pmu      Xilinx ZynqMP PMU machine (big endian) (deprecated)
qemu-system-microblazeel -M help
Supported machines are:
none                 empty machine
petalogix-ml605      PetaLogix linux refdesign for xilinx ml605 (little 
endian)
petalogix-s3adsp1800-be PetaLogix linux refdesign for xilinx Spartan 
3ADSP1800 (big endian)
petalogix-s3adsp1800 PetaLogix linux refdesign for xilinx Spartan 
3ADSP1800 (little endian) (alias of petalogix-s3adsp1800-le)
petalogix-s3adsp1800-le PetaLogix linux refdesign for xilinx Spartan 
3ADSP1800 (little endian) (default)
xlnx-zynqmp-pmu      Xilinx ZynqMP PMU machine (little endian)

1 architecture declined in 2 binaries, total of 10 machines

3/ Once the deprecation period passed and we can merge the 2 binaries:

$ qemu-system-microblaze -M help
Supported machines are:
none                 empty machine
petalogix-ml605      PetaLogix linux refdesign for xilinx ml605 (little 
endian)
petalogix-s3adsp1800-be PetaLogix linux refdesign for xilinx Spartan 
3ADSP1800 (big endian)
petalogix-s3adsp1800-le PetaLogix linux refdesign for xilinx Spartan 
3ADSP1800 (little endian)
xlnx-zynqmp-pmu      Xilinx ZynqMP PMU machine (little endian)

1 architecture, 1 binary, 4 machines (which could be reduced to 3 if
we want a default endianness for the s3adsp1800).

Due to the deprecation policy, step 2/ is necessary to reach 3/.