xen: update documentation with vxn/containerd integration and runtime tests

README-xen.md:
- Add vxn and containerd integration section describing all execution
  paths (containerd, vxn standalone, vdkr/vpdmn, native Docker/Podman)
- Add memory requirements section explaining QB_MEM_VALUE=1024 is
  insufficient for vxn/vctr and documenting qemuparams="-m 4096"
- Add runtime tests section with build prerequisites, test commands,
  and skip behavior
- Fix x86-64 runqemu command to include qemuparams="-m 4096"

vxn/README.md:
- Add testing section referencing the pytest runtime test suite

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/recipes-core/vxn/README.md b/recipes-core/vxn/README.md
index 35802e31..2c0ca0ec 100644
--- a/recipes-core/vxn/README.md
+++ b/recipes-core/vxn/README.md
@@ -139,6 +139,32 @@ VM isolation.
 - `vctr`/`ctr` (containerd) — CNI is separate and opt-in
 - `vdkr`/`vpdmn` — Handle networking independently via xenbr0
 
+## Testing
+
+Automated runtime tests boot xen-image-minimal and verify vxn end-to-end:
+
+```bash
+pip install pytest pexpect
+
+# All Xen runtime tests (requires built image + KVM)
+cd meta-virtualization
+pytest tests/test_xen_runtime.py -v --machine qemux86-64
+
+# vxn/containerd tests only
+pytest tests/test_xen_runtime.py -v -k "Vxn or Containerd"
+
+# Skip network-dependent tests
+pytest tests/test_xen_runtime.py -v -m "boot and not network"
+```
+
+The tests boot the image with `qemuparams="-m 4096"` to provide enough
+memory for Dom0 + bundled guests + vxn/vctr guests. Tests detect
+available features inside Dom0 and skip gracefully when components are
+not installed.
+
+See `tests/README.md` for full test documentation and `recipes-extended/images/README-xen.md`
+for build prerequisites at each test tier.
+
 ## Debugging
 
 ```bash