Hello Peter,
On Fri, Jan 15, 2021 at 12:31:10PM +0000, fixed-term.peter.jacobi@sojus-software.de wrote:
Hi, after trying to understand a little bit deeper at the "arm_vmm.run" file in an effort to expand this to run 2 VMMs parallel, I faced some issues I do not understand well. So I hope to get here your expert help to clarify what I missundersand. 1.- Arm-Run-File: I modified the vmm_arm.run adding a 2nd component vm2 as you can see in the attached file. The result of this you can see in the attached result-file. So no entry point is found for this 2nd component.
when looking into your example, I can see that you duplicated the terminal_expect_send test-component only, but not the vmm (and thereby vm), nor the terminal_crosslink component. Instead you connect the additional terminal_expect_send component to the terminal_crosslink in addition.
Before explaining what is going wrong, I'll explain the original vmm_arm.run script in more detail, as well as the involved components.
The vmm_arm.script, like most run-scripts that are listed in `tool/autopilot.list`, is used to automatically test every night a certain feature. In this case, the ARM virtualization extensions resp. our hypervisor and VMM. It is therefore not meant to be used interactively. On the other hand, we want to test a bit of the interactive features of the VMM, namely its virtio console model. The virtio console model in the VMM maps to Genode's Terminal interface. That means, the Terminal session route of the VMM component can be used to interact with the guest VM's (Linux) console. It is connected to the terminal_crosslink component. The terminal_crosslink is a simple server component which connects the RX line of one Terminal client with the TX line of another one and vice versa. The other Terminal client, which is cross-linked with the VMM, in this case is the terminal_expect_send component. This is a very simple `expect`-like component, which looks for a certain string in its Terminal input, and if it received that input sends another string. In our example it is configured like the following:
<config expect="/ #" send="ls" verbose="yes"/>
That means it waits for the terminal prompt "/ #", and then sends the command "ls". Moreover, it prints all received characters to the LOG output. Therefore, we cann see the interaction of terminal_expect_send and VMM. That is also the reason, why the terminal_expect_send components name is "vm", although it isn't actually the VM, because it prints all console output of the VM to the LOG output. Therefore, an observer looks at its output as the output of the VM. The VM itself is not described discretely in the init configuration of the run-script. It is always managed by the VMM.
To sum it up: if you want more than one VM, you need to start another VMM. You should not connect more clients to the same terminal_crosslink component than the two clients that should interact with each other.
If you want to play around with the VMM in more detail. and learn more about its interaction, I would recommend to you to replace the terminal_expect_send and terminal_crosslink with a Terminal with whom you can directly interact. Either you use networking and the tcp_terminal, or you take a graphical environment as starting point and start a Terminal that uses the GUI server. If you simply want to duplicate the VM in the vmm_arm example, you have to duplicate the VMM, terminal_crosslink, and terminal_expect_send component as well.
2.- Source, wandering through the source structure /repos/os/src/ I found the "terminal_expect_send" in the test directory. What do i expect to find in the os-test-directory structure? Greetings, Peter
In `src/test` in the sub-repositories in general, or in `os/src/test` in particular, you'll find small components to e.g. showcase the usage of an API, or to test-control a certain component. Those components are typically not meant to be used as general-purpose, productive components.
Best regards Stefan
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