The checkpoint feature may not have successfully saved and restored some data. about gem5

[powerjg]

Sounds like PMP register state isn't saved at the checkpoint. Thanks for the detailed bug report!

Feel free to contribute a change to fix this! I can't give an estimate for when someone on my team will be able to take a look, but it will be at least a week or more.

[despotx]

I have added serialization and deserialization code for PMP. After restoring from a checkpoint, I did not encounter PMP access errors during the subsequent execution of the secure program. However, a new issue emerged, and here is the terminal output.

At this point, the TTY has become unresponsive, and attempting to save the checkpoint and restore results in an inability to proceed in the terminal. How can I locate and resolve this issue. More specifically, how can I overview what data is stored in the checkpoint and which data can be omitted to reduce overhead。

[powerjg]

You can look at the .cpt file to see all of the data that's stored.

To debug this, here's what I'd do:

• Use the Exec debug flag after you take the checkpoint for the next few thousand instructions and then do the same thing on the checkpoint restore. I would compare these traces and look for anything that seems "off"
• My first guess is that there's something missing in the takeOverFrom function somewhere in the RISC-V ISA.

[despotx]

I think resolving this issue might be a major undertaking. I saw in the gem5 documentation under the checkpoints section as

shown in the figure below.

Unfortunately, in my configuration, I am using the Ruby memory model while also using the MESI protocol. I don't quite

understand what the relationship is between checkpoints and cache protocols.

I see that the serialization and deserialization methods are defined in the base class Serializable, and SimObject is a subclass of

Serializable. At the same time, almost all components (including storage components, temporary ones, and those that are commit

targets) inherit from SimObject. Not all storage components implement serialization and deserialization methods, right? So why

would different cache protocols affect checkpoints? These questions might seem silly, but I need to emphasize that I am a

beginner with gem5, and I am already frazzled by the extremely slow simulation speed.