xref: /openbmc/qemu/docs/system/arm/xenpvh.rst (revision c16de0d9)
1Xen Device Emulation Backend (``xenpvh``)
2=========================================
3
4This machine is a little unusual compared to others as QEMU just acts
5as an IOREQ server to register/connect with Xen Hypervisor. Control of
6the VMs themselves is left to the Xen tooling.
7
8When TPM is enabled, this machine also creates a tpm-tis-device at a
9user input tpm base address, adds a TPM emulator and connects to a
10swtpm application running on host machine via chardev socket. This
11enables xenpvh to support TPM functionalities for a guest domain.
12
13More information about TPM use and installing swtpm linux application
14can be found in the :ref:`tpm-device` section.
15
16Example for starting swtpm on host machine:
17
18.. code-block:: console
19
20    mkdir /tmp/vtpm2
21    swtpm socket --tpmstate dir=/tmp/vtpm2 \
22      --ctrl type=unixio,path=/tmp/vtpm2/swtpm-sock &
23
24Sample QEMU xenpvh commands for running and connecting with Xen:
25
26.. code-block:: console
27
28    qemu-system-aarch64 -xen-domid 1 \
29      -chardev socket,id=libxl-cmd,path=qmp-libxl-1,server=on,wait=off \
30      -mon chardev=libxl-cmd,mode=control \
31      -chardev socket,id=libxenstat-cmd,path=qmp-libxenstat-1,server=on,wait=off \
32      -mon chardev=libxenstat-cmd,mode=control \
33      -xen-attach -name guest0 -vnc none -display none -nographic \
34      -machine xenpvh -m 1301 \
35      -chardev socket,id=chrtpm,path=tmp/vtpm2/swtpm-sock \
36      -tpmdev emulator,id=tpm0,chardev=chrtpm -machine tpm-base-addr=0x0C000000
37
38In above QEMU command, last two lines are for connecting xenpvh QEMU to swtpm
39via chardev socket.
40