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Xen Test Framework
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This is both a framework for creating microkernel-based tests, and a suite of tests built using the framework. (This is not the Xen Project's CI / Continuous Integration / automated push gate system. For that, see OSSTest.)
The microkernel boots, runs a set of related tests, and report the overall status on the configured consoles. Automating a suite of tests simply involves booting each microkernel and checking the final printed line on the guest's console.
The build system and library abstractions are specifically designed to make it easy to write code once and compile it for multiple different environments (virtual machines).
The current environments supported are:
| Environment | Guest | Width | Paging |
|---|---|---|---|
pv32pae | PV | 32bit | PAE |
pv64 | PV | 64bit | Long mode |
hvm32 | HVM | 32bit | None |
hvm32pse | HVM | 32bit | PSE |
hvm32pae | HVM | 32bit | PAE |
hvm64 | HVM | 64bit | Long mode |
Requirements:
For x86:
-std=gnu99, -m64, and -m32.CC="clang".hvm64 tests would prefer to use the elf32-x86-64 format, so they both load and disassemble correctly. In the absence of x32 support, elf32-i386 will be used which will load correctly, but disassemble incorrectly.To obtain and build:
$ git clone git://xenbits.xen.org/xtf.git $ cd xtf $ make -j4
To run tests on a Xen host: (see Errata first)
# ./xtf-runner test-pv64-example Executing 'xl create -p tests/example/test-pv64-example.cfg' Parsing config from tests/example/test-pv64-example.cfg Executing 'xl console test-pv64-example' Executing 'xl unpause test-pv64-example' --- Xen Test Framework --- Environment: PV 64bit (Long mode 4 levels) Hello World Test result: SUCCESS Combined test results: test-pv64-example SUCCESS
xl accepts either an absolute path, or certain relative paths (/etc/xen/ or $CWD for kernel=, $libdir/xen/boot for firmware_override=). The default xtfdir= is configured correctly for running the tests out of the build working tree. If the tests are running elsewhere, use make install DESTDIR=$X xtfdir=$Y to configure absolute paths appropriately for the test system.CONFIG_HVM_FEP and booted with ‘'hvm_fep’` to enable the runtime use of FEP. These tests will detect if FEP is unavailable and exit with an error.Error: operand size mismatch for push.A fix 7fe76f02413f was backported into Bintuils 2.41 stable branch.
The Xen Test Framework grew out of the work done to debug XSA-106. As reported, Xen's instruction emulator failed to perform dpl checks for instructions generating software exceptions, which allowed guest userspace to bypass a security check set up by the guest kernel. Further investigation showed that the exception frames which resulted from emulation were incorrect; specifically that the reported %eip was usually wrong.
A test kernel was written to compare the exception frames of faults and traps when executed by hardware, and when emulated by the instruction emulator. On doing this, it was observed that different hardware was behaving differently (depending on the degree of hardware assistance available), and some CPUs were not behaving as described in the manual.
Once the embargo on XSA-106 lifted, changesets 7dfa94c6212b, ecf5678200ad and 36ebf14ebe60 were the eventual bugfixes which caused Xen to inject software exceptions correctly.
The test was deemed, in principle, to be a good project to invest some time in and to clean up for more general use. Naturally therefore, the cleanup progressed only in the authors copious free time, when more important tasks were not being done.
Moving forward by a year, the author was dismayed to discover that the XSA-156 release contained a regression (causing infinite loops inside guests which used hardware debugging facilities, fixed in 0747bc8b4d85) which would have been caught by the original test for XSA-106, had that test been in a usable state.
It now is.
1.9.4