| commit | e14e6ba56f6e9597e774ab0e28f9ba9e5f5a06c9 | [log] [tgz] |
|---|---|---|
| author | Alexandru Elisei <alexandru.elisei@arm.com> | Fri Jan 31 16:37:20 2020 +0000 |
| committer | Andrew Jones <drjones@redhat.com> | Fri Apr 03 09:40:33 2020 +0200 |
| tree | 158a52f727ad6cb4c133757b2d5569bbbd85e635 | |
| parent | 2087da55d7a253bfd02ea4b184a0e4af9b1ec5dd [diff] |
arm/arm64: psci: Don't run C code without stack or vectors The psci test performs a series of CPU_ON/CPU_OFF cycles for CPU 1. This is done by setting the entry point for the CPU_ON call to the physical address of the C function cpu_psci_cpu_die. The compiler is well within its rights to use the stack when generating code for cpu_psci_cpu_die. However, because no stack initialization has been done, the stack pointer is zero, as set by KVM when creating the VCPU. This causes a data abort without a change in exception level. The VBAR_EL1 register is also zero (the KVM reset value for VBAR_EL1), the MMU is off, and we end up trying to fetch instructions from address 0x200. At this point, a stage 2 instruction abort is generated which is taken to KVM. KVM interprets this as an instruction fetch from an I/O region, and injects a prefetch abort into the guest. Prefetch abort is a synchronous exception, and on guest return the VCPU PC will be set to VBAR_EL1 + 0x200, which is... 0x200. The VCPU ends up in an infinite loop causing a prefetch abort while fetching the instruction to service the said abort. To avoid all of this, lets use the assembly function halt as the CPU_ON entry address. Also, expand the check to test that we only get PSCI_RET_SUCCESS exactly once, as we're never offlining the CPU during the test. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Andrew Jones <drjones@redhat.com>
See http://www.linux-kvm.org/page/KVM-unit-tests for a high-level description of this project, as well as running tests and adding tests HOWTOs.
This directory contains sources for a KVM test suite.
To create the test images do:
./configure make
in this directory. Test images are created in ./ARCH/*.flat
The tests can be built as standalone. To create and use standalone tests do:
./configure make standalone (send tests/some-test somewhere) (go to somewhere) ./some-test
make install will install all tests in PREFIX/share/kvm-unit-tests/tests, each as a standalone test.
Then use the runner script to detect the correct invocation and invoke the test:
./x86-run ./x86/msr.flat
or:
./run_tests.sh
to run them all.
By default the runner script searches for a suitable QEMU binary in the system. To select a specific QEMU binary though, specify the QEMU=path/to/binary environment variable:
QEMU=/tmp/qemu/x86_64-softmmu/qemu-system-x86_64 ./x86-run ./x86/msr.flat
To select an accelerator, for example “kvm” or “tcg”, specify the ACCEL=name environment variable:
ACCEL=kvm ./x86-run ./x86/msr.flat
The test case may need specific runtime configurations, for example, extra QEMU parameters and time to execute limited, the runner script reads those information from a configuration file found at ./ARCH/unittests.cfg.
The configuration file also contain the groups (if any) each test belong to. So that a given group can be executed by specifying its name in the runner's -g option.
Unit tests use QEMU's ‘-append args...’ parameter for command line inputs, i.e. all args will be available as argv strings in main(). Additionally a file of the form
KEY=VAL KEY2=VAL ...
may be passed with ‘-initrd file’ to become the unit test's environ, which can then be accessed in the usual ways, e.g. VAL = getenv(“KEY”). Any key=val strings can be passed, but some have reserved meanings in the framework. The list of reserved environment variables is below
QEMU_ACCEL either kvm or tcg QEMU_VERSION_STRING string of the form `qemu -h | head -1` KERNEL_VERSION_STRING string of the form `uname -r`
Additionally these self-explanatory variables are reserved
QEMU_MAJOR, QEMU_MINOR, QEMU_MICRO, KERNEL_VERSION, KERNEL_PATCHLEVEL, KERNEL_SUBLEVEL, KERNEL_EXTRAVERSION
Some tests are not safe to run by default, as they may crash the host. kvm-unit-tests provides two ways to handle tests like those.
Adding ‘nodefault’ to the groups field for the unit test in the unittests.cfg file. When a unit test is in the nodefault group it is only run when invoked
a) independently, ARCH-run ARCH/test
b) by specifying any other non-nodefault group it is in, groups = nodefault,mygroup : ./run_tests.sh -g mygroup
c) by specifying all tests should be run, ./run_tests.sh -a
Making the test conditional on errata in the code,
if (ERRATA(abcdef012345)) {
do_unsafe_test();
}
With the errata condition the unsafe unit test is only run when
a) the ERRATA_abcdef012345 environment variable is provided and ‘y’
b) the ERRATA_FORCE environment variable is provided and ‘y’
c) by specifying all tests should be run, ./run_tests.sh -a (The -a switch ensures the ERRATA_FORCE is provided and set to ‘y’.)
The ./errata.txt file provides a mapping of the commits needed by errata conditionals to their respective minimum kernel versions. By default, when the user does not provide an environ, then an environ generated from the ./errata.txt file and the host's kernel version is provided to all unit tests.
.: configure script, top-level Makefile, and run_tests.sh ./scripts: helper scripts for building and running tests ./lib: general architecture neutral services for the tests ./lib/<ARCH>: architecture dependent services for the tests ./<ARCH>: the sources of the tests and the created objects/images
See ./ARCH/README for architecture specific documentation.
Currently there is a mix of indentation styles so any changes to existing files should be consistent with the existing style. For new files:
Exceptions:
Patches are welcome at the KVM mailing list kvm@vger.kernel.org.
Please prefix messages with: [kvm-unit-tests PATCH]
You can add the following to .git/config to do this automatically for you:
[format]
subjectprefix = kvm-unit-tests PATCH
Additionally it‘s helpful to have a common order of file types in patches. Our chosen order attempts to place the more declarative files before the code files. We also start with common code and finish with unit test code. git-diff’s orderFile feature allows us to specify the order in a file. The orderFile we use is scripts/git.difforder; adding the config with git config diff.orderFile scripts/git.difforder enables it.