hw/arm/imx8mp-evk: Add KVM support

Allows the imx8mp-evk machine to run guests with KVM acceleration.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Message-id: 20251101120130.236721-2-shentey@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

docs/system/arm/imx8mp-evk.rst

@@ -60,3 +60,22 @@ Now that everything is prepared the machine can be started as follows:
       -dtb imx8mp-evk.dtb \
       -append "root=/dev/mmcblk2p2" \
       -drive file=sdcard.img,if=sd,bus=2,format=raw,id=mmcblk2
+
+
+KVM Acceleration
+----------------
+
+To enable hardware-assisted acceleration via KVM, append
+``-accel kvm -cpu host`` to the command line. While this speeds up performance
+significantly, be aware of the following limitations:
+
+* The ``imx8mp-evk`` machine is not included under the "virtualization use case"
+  of :doc:`QEMU's security policy </system/security>`. This means that you
+  should not trust that it can contain malicious guests, whether it is run
+  using TCG or KVM. If you don't trust your guests and you're relying on QEMU to
+  be the security boundary, you want to choose another machine such as ``virt``.
+* Rather than Cortex-A53 CPUs, the same CPU type as the host's will be used.
+  This is a limitation of KVM and may not work with guests with a tight
+  dependency on Cortex-A53.
+* No EL2 and EL3 exception levels are available which is also a KVM limitation.
+  Direct kernel boot should work but running U-Boot, TF-A, etc. won't succeed.