Introduce bsd-user-qemu and run-{shell,user}-riscv64-purecap targets. by kwitaszczyk · Pull Request #264 · CTSRD-CHERI/cheribuild

kwitaszczyk · 2021-12-04T17:00:12Z

The targets use QEMU code from the qemu-cheri-bsd-user branch.

Examples:

Build the BSD user mode:
```
./cheribuild.py bsd-user-qemu
```

Run a CheriABI CHERI-RISC-V command:

./cheribuild.py run-user-riscv64-purecap \
    --run-user/command  \
    '/zdata/cheri/output/rootfs-riscv64-purecap/bin/cheribsdtest-purecap-dynamic -a'

Run a CheriABI CHERI-RISC-V command with the root directory changed to a sysroot:

sudo ./cheribuild.py --allow-running-as-root run-user-riscv64-purecap \
    --run-user/chroot --run-user/command \
    'cheribsdtest-purecap-dynamic -a'

Run a CheriABI CHERI-RISC-V shell in a jail with the root directory changed to a sysroot and devfs(8) mounted:

sudo ./cheribuild.py --allow-running-as-root run-shell-riscv64-purecap \
    --run-shell/jail --run-shell/jail-extra-args mount.devfs

jrtc27 · 2021-12-08T15:57:31Z

README.md

 - `freebsd-<architecture>` builds and installs [freebsd/freebsd](https://github.com/freebsd/freebsd).
 - `disk-image-freebsd-<architecture>` creates a FreeBSD disk-image.
 - `run-freebsd-<architecture>` launches QEMU with the FreeBSD disk image.
+- `run-shell-<architecture>` launches a shell with the QEMU user mode in a CheriBSD sysroot.


As mentioned on Slack in the past, I think run-user-shell does a better job of namespacing it as a qemu-user thing, since arguably run does get you a shell (once you log in)

Done: 10d522b .

Besides run-user-shell, we also have run-user to execute an arbitrary command. What do you think about that target name? I wonder if we should remove run-user-shell and only have run-user which by default executes /bin/sh, unless --run-user/command is specified.

pycheribuild/projects/build_qemu.py

jrtc27 · 2021-12-08T16:04:18Z

pycheribuild/projects/build_qemu.py

+    repository = GitRepository("https://github.com/CTSRD-CHERI/qemu.git",
+                               default_branch="qemu-cheri-bsd-user",
+                               force_branch=True)
+    native_install_dir = DefaultInstallDir.BSD_USER_SDK


You shouldn't need a whole new enum for this, just copy upstream-qemu's approach?

BuildUpstreamQEMU's way is quite complex. Wouldn't be it easier to maintain a separate enum for this?

Instead, we could add a comment the enum should be removed once the BSD user mode is merged to qemu-cheri (which can take quite a while).

Does this install anything other than the qemu-user binaries? If not we could reuse the same installation directory?

jrtc27 · 2021-12-08T16:07:53Z

pycheribuild/projects/build_qemu.py

+    hide_options_from_help = True
+
+    @classmethod
+    def qemu_cheri_binary(cls, caller: SimpleProject, xtarget: CrossCompileTarget = None, absolute_path=True):


This is going to need to be a separate method as otherwise we won't be able to have a single target that builds both

I'm not sure if we're going to be able to build both a system mode and a user mode with a single configure. The BSD user mode needs to be static for Poudriere (it copies a single binary to a jail).

Would we want to build system modes with --static? If not, would we want to add --static per mode or target?

pycheribuild/projects/run_qemu.py

pycheribuild/qemu_utils.py

kwitaszczyk

I'm aware the branch must be rebased before it can be merged to qemu-cheri. I'll do it once the current changes are accepted as I'd have to force push the rebase and hence ruin this review.

kwitaszczyk · 2022-02-22T14:00:19Z

README.md

 - `freebsd-<architecture>` builds and installs [freebsd/freebsd](https://github.com/freebsd/freebsd).
 - `disk-image-freebsd-<architecture>` creates a FreeBSD disk-image.
 - `run-freebsd-<architecture>` launches QEMU with the FreeBSD disk image.
+- `run-shell-<architecture>` launches a shell with the QEMU user mode in a CheriBSD sysroot.


Done: 10d522b .

Besides run-user-shell, we also have run-user to execute an arbitrary command. What do you think about that target name? I wonder if we should remove run-user-shell and only have run-user which by default executes /bin/sh, unless --run-user/command is specified.

pycheribuild/qemu_utils.py

kwitaszczyk · 2022-02-22T14:15:39Z

pycheribuild/projects/build_qemu.py

+    repository = GitRepository("https://github.com/CTSRD-CHERI/qemu.git",
+                               default_branch="qemu-cheri-bsd-user",
+                               force_branch=True)
+    native_install_dir = DefaultInstallDir.BSD_USER_SDK


BuildUpstreamQEMU's way is quite complex. Wouldn't be it easier to maintain a separate enum for this?

Instead, we could add a comment the enum should be removed once the BSD user mode is merged to qemu-cheri (which can take quite a while).

kwitaszczyk · 2022-02-22T14:57:37Z

pycheribuild/projects/build_qemu.py

+    hide_options_from_help = True
+
+    @classmethod
+    def qemu_cheri_binary(cls, caller: SimpleProject, xtarget: CrossCompileTarget = None, absolute_path=True):


I'm not sure if we're going to be able to build both a system mode and a user mode with a single configure. The BSD user mode needs to be static for Poudriere (it copies a single binary to a jail).

Would we want to build system modes with --static? If not, would we want to add --static per mode or target?

pycheribuild/projects/run_qemu.py

pycheribuild/projects/build_qemu.py

The target builds the QEMU CheriABI user mode targets from the qemu-cheri-bsd-user branch in CTSRD-CHERI/QEMU and installs it in a separate SDK directory. This target doesn't use SMB and hence doesn't require SMB support.

A run-<architecture>-shell target launches a shell with the QEMU user mode in a CheriBSD sysroot. * Since the run-<architecture>-shell targets run a QEMU user mode binary, different QEMU flags are required, as opposed to the run-<architecture> targets. Modify the QemuOptions class to provide separate methods to construct argument lists for a system or a user mode binary; * Instead of using the LaunchQEMUBase class, introduce the LaunchBsdUserQEMUBase class that runs a user mode binary; * Instead of using the LaunchCheriBSD class, introduce the LaunchCheriBSDShell class that creates run-<architecture> targets with the "-shell" suffix; * Describe the run-<architecture>-shell targets in README.

A run-<architecture>-exec target executes a command passed with an option --exec/command. Additionally, one of the following options can be used: * --exec/chroot tells cheribuild to change a root directory to a sysroot before executing the command; * --exec/jail tells cheribuild to enter a jail with a sysroot before executing the command. The flags --exec/{chroot,jail} require cheribuild to be run as root. At the moment, --allow-running-as-root can be used to run cheribuild with sudo but this option shouldn't be used without the flags --exec/{chroot,jail}. Additionally, --skip-update is recommended when carefully using --allow-running-as-root.

@jrtc27

* Rename the targets to run-{shell,user}-<architecture> for consistency with other targets; * Describe the run-user-<architecture> in README. Pointed out by: @jrtc27

The jail-extra-args options allow to pass extra jail parameters to jail(8), e.g. to mount devfs(8).

BuildSystemQEMU is a parent class for all classes for system-mode targets. Thanks to this class, two issues are resolved: * BuildQEMUBase was adding --disable-bsd-user to configure flags also for user-mode targets; * BuildQEMU was adding morello-softmmu to the default targets if a QEMU branch includes Morello support. BuildBsdUserQEMU can manage its own list of targets and not use configuration flags only related to the system mode now.

Extend the bsd-user-qemu target to build BSD user modes for all targets we're interested in: aarch64, riscv64, riscv64c. Morello will be added to the above list once it's working.

* Rename the target to indiciate with a 'user' subword it's related to the BSD user mode (built with the bsd-user-qemu cheribuild target); * Update class names to match target names better. Pointed out by: jrtc27

Allow to specify an ELF interpreter path for the run-user and run-user-shell targets. The interpreter path can be different than an encoded one in an ELF binary in multi-ABI environments, e.g. a Poudriere jail.

Map the guest address space not to overlap with a host address space.

Pointed out by: jrtc27

AbstractLaunchFreeBSDProgram was the only child class of the LaunchBsdUserQEMUBase class. Instead of introducing another abstraction, move AbstractLaunchFreeBSDProgram login into LaunchBsdUserQEMUBase. Pointed out by: jrtc27

Set the default value of a command to execute with the user mode to /bin/sh within a rootfs.

The command should be computed depending on a target context. In case of run-user-shell, we'd like to append a rootfs path if the shell is not executed with chroot nor jail. Pointed out by: jrtc27

Reduce a number of additional abstractions required for the user mode support that should be eventually removed once the user mode is merged into the qemu-cheri branch. This change uses a hack to always pass --disabled-bsd-user to configure and later pass --enable-bsd-user to overwrite it. Pointed out by: jrtc27

kwitaszczyk self-assigned this Dec 4, 2021

kwitaszczyk requested a review from jrtc27 December 8, 2021 11:58

jrtc27 reviewed Dec 8, 2021

View reviewed changes

kwitaszczyk commented Feb 22, 2022

View reviewed changes

kwitaszczyk requested a review from jrtc27 March 2, 2022 11:42

kwitaszczyk force-pushed the qemu-cheri-bsd-user branch from 87d2f95 to b557b57 Compare May 13, 2022 14:48

kwitaszczyk added 19 commits March 27, 2023 16:20

Introduce the bsd-user-qemu target.

b23da30

The target builds the QEMU CheriABI user mode targets from the qemu-cheri-bsd-user branch in CTSRD-CHERI/QEMU and installs it in a separate SDK directory. This target doesn't use SMB and hence doesn't require SMB support.

Rename run-<architecture>-{shell,exec} targets.

8c67455

* Rename the targets to run-{shell,user}-<architecture> for consistency with other targets; * Describe the run-user-<architecture> in README. Pointed out by: @jrtc27

Introduce --run-{shell,user}/jail-extra-args.

3bb34a6

The jail-extra-args options allow to pass extra jail parameters to jail(8), e.g. to mount devfs(8).

Add QEMU BSD user mode options for Jenkins.

efe4075

Mock the BSD user-mode SDK directory path.

6a3da25

Make Flake8 happy.

b664350

Build BSD user modes for aarch64 and riscv64.

be4fd63

Extend the bsd-user-qemu target to build BSD user modes for all targets we're interested in: aarch64, riscv64, riscv64c. Morello will be added to the above list once it's working.

Build the Morello user mode by default.

ddfd600

Rename the run-shell target to run-user-shell.

d466115

* Rename the target to indiciate with a 'user' subword it's related to the BSD user mode (built with the bsd-user-qemu cheribuild target); * Update class names to match target names better. Pointed out by: jrtc27

Add an interpreter path option.

553bf45

Allow to specify an ELF interpreter path for the run-user and run-user-shell targets. The interpreter path can be different than an encoded one in an ELF binary in multi-ABI environments, e.g. a Poudriere jail.

Map a guest address space at 0x100000000.

c6d823e

Map the guest address space not to overlap with a host address space.

Remove an unused argument.

cd8b16e

Pointed out by: jrtc27

Remove AbstractLaunchFreeBSDProgram.

7427478

AbstractLaunchFreeBSDProgram was the only child class of the LaunchBsdUserQEMUBase class. Instead of introducing another abstraction, move AbstractLaunchFreeBSDProgram login into LaunchBsdUserQEMUBase. Pointed out by: jrtc27

Set a default value for --run-user/command.

48dc528

Set the default value of a command to execute with the user mode to /bin/sh within a rootfs.

Compute a command within a target context.

d4c322e

The command should be computed depending on a target context. In case of run-user-shell, we'd like to append a rootfs path if the shell is not executed with chroot nor jail. Pointed out by: jrtc27

kwitaszczyk force-pushed the qemu-cheri-bsd-user branch from b557b57 to 1590f85 Compare March 27, 2023 16:22

arichardson changed the base branch from master to main April 4, 2023 21:40

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kwitaszczyk commented Dec 4, 2021

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