Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-docs-xen-updates-100321-2' into staging

Testing, guest-loader and other misc tweaks

  - add warning text to quickstart example
  - add CFI tests to CI
  - use --arch-only for docker pre-requisites
  - fix .editorconfig for emacs
  - add guest-loader for Xen-like hypervisor testing
  - move generic-loader docs into manual proper
  - move semihosting out of hw/

# gpg: Signature made Wed 10 Mar 2021 15:35:31 GMT
# gpg:                using RSA key 6685AE99E75167BCAFC8DF35FBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>" [full]
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* remotes/stsquad/tags/pull-testing-docs-xen-updates-100321-2:
  semihosting: Move hw/semihosting/ -> semihosting/
  semihosting: Move include/hw/semihosting/ -> include/semihosting/
  tests/avocado: add boot_xen tests
  docs: add some documentation for the guest-loader
  docs: move generic-loader documentation into the main manual
  hw/core: implement a guest-loader to support static hypervisor guests
  device_tree: add qemu_fdt_setprop_string_array helper
  hw/riscv: migrate fdt field to generic MachineState
  hw/board: promote fdt from ARM VirtMachineState to MachineState
  .editorconfig: update the automatic mode setting for Emacs
  tests/docker: Use --arch-only when building Debian cross image
  gitlab-ci.yml: Add jobs to test CFI flags
  gitlab-ci.yml: Allow custom # of parallel linkers
  tests/docker: add a test-tcg for building then running check-tcg
  docs/system: add a gentle prompt for the complexity to come

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

5 files changed, 183 insertions, 0 deletions

diff --git a/docs/system/generic-loader.rst b/docs/system/generic-loader.rst
new file mode 100644
index 0000000000..6bf8a4eb48
--- /dev/null
+++ b/docs/system/generic-loader.rst
@@ -0,0 +1,117 @@
+..
+   Copyright (c) 2016, Xilinx Inc.
+
+This work is licensed under the terms of the GNU GPL, version 2 or later.  See
+the COPYING file in the top-level directory.
+
+Generic Loader
+--------------
+
+The 'loader' device allows the user to load multiple images or values into
+QEMU at startup.
+
+Loading Data into Memory Values
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+The loader device allows memory values to be set from the command line. This
+can be done by following the syntax below::
+
+   -device loader,addr=<addr>,data=<data>,data-len=<data-len> \
+                   [,data-be=<data-be>][,cpu-num=<cpu-num>]
+
+``<addr>``
+  The address to store the data in.
+
+``<data>``
+  The value to be written to the address. The maximum size of the data
+  is 8 bytes.
+
+``<data-len>``
+  The length of the data in bytes. This argument must be included if
+  the data argument is.
+
+``<data-be>``
+  Set to true if the data to be stored on the guest should be written
+  as big endian data. The default is to write little endian data.
+
+``<cpu-num>``
+  The number of the CPU's address space where the data should be
+  loaded. If not specified the address space of the first CPU is used.
+
+All values are parsed using the standard QemuOps parsing. This allows the user
+to specify any values in any format supported. By default the values
+will be parsed as decimal. To use hex values the user should prefix the number
+with a '0x'.
+
+An example of loading value 0x8000000e to address 0xfd1a0104 is::
+
+    -device loader,addr=0xfd1a0104,data=0x8000000e,data-len=4
+
+Setting a CPU's Program Counter
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The loader device allows the CPU's PC to be set from the command line. This
+can be done by following the syntax below::
+
+     -device loader,addr=<addr>,cpu-num=<cpu-num>
+
+``<addr>``
+  The value to use as the CPU's PC.
+
+``<cpu-num>``
+  The number of the CPU whose PC should be set to the specified value.
+
+All values are parsed using the standard QemuOpts parsing. This allows the user
+to specify any values in any format supported. By default the values
+will be parsed as decimal. To use hex values the user should prefix the number
+with a '0x'.
+
+An example of setting CPU 0's PC to 0x8000 is::
+
+    -device loader,addr=0x8000,cpu-num=0
+
+Loading Files
+^^^^^^^^^^^^^
+
+The loader device also allows files to be loaded into memory. It can load ELF,
+U-Boot, and Intel HEX executable formats as well as raw images.  The syntax is
+shown below:
+
+    -device loader,file=<file>[,addr=<addr>][,cpu-num=<cpu-num>][,force-raw=<raw>]
+
+``<file>``
+  A file to be loaded into memory
+
+``<addr>``
+  The memory address where the file should be loaded. This is required
+  for raw images and ignored for non-raw files.
+
+``<cpu-num>``
+  This specifies the CPU that should be used. This is an
+  optional argument and will cause the CPU's PC to be set to the
+  memory address where the raw file is loaded or the entry point
+  specified in the executable format header. This option should only
+  be used for the boot image. This will also cause the image to be
+  written to the specified CPU's address space. If not specified, the
+  default is CPU 0. <force-raw> - Setting force-raw=on forces the file
+  to be treated as a raw image. This can be used to load supported
+  executable formats as if they were raw.
+
+All values are parsed using the standard QemuOpts parsing. This allows the user
+to specify any values in any format supported. By default the values
+will be parsed as decimal. To use hex values the user should prefix the number
+with a '0x'.
+
+An example of loading an ELF file which CPU0 will boot is shown below::
+
+    -device loader,file=./images/boot.elf,cpu-num=0
+
+Restrictions and ToDos
+^^^^^^^^^^^^^^^^^^^^^^
+
+At the moment it is just assumed that if you specify a cpu-num then
+you want to set the PC as well. This might not always be the case. In
+future the internal state 'set_pc' (which exists in the generic loader
+now) should be exposed to the user so that they can choose if the PC
+is set or not.
+
+
diff --git a/docs/system/guest-loader.rst b/docs/system/guest-loader.rst
new file mode 100644
index 0000000000..37d03cbd89
--- /dev/null
+++ b/docs/system/guest-loader.rst
@@ -0,0 +1,54 @@
+..
+   Copyright (c) 2020, Linaro
+
+Guest Loader
+------------
+
+The guest loader is similar to the `generic-loader` although it is
+aimed at a particular use case of loading hypervisor guests. This is
+useful for debugging hypervisors without having to jump through the
+hoops of firmware and boot-loaders.
+
+The guest loader does two things:
+
+  - load blobs (kernels and initial ram disks) into memory
+  - sets platform FDT data so hypervisors can find and boot them
+
+This is what is typically done by a boot-loader like grub using it's
+multi-boot capability. A typical example would look like:
+
+.. parsed-literal::
+
+  |qemu_system| -kernel ~/xen.git/xen/xen \
+    -append "dom0_mem=1G,max:1G loglvl=all guest_loglvl=all" \
+    -device guest-loader,addr=0x42000000,kernel=Image,bootargs="root=/dev/sda2 ro console=hvc0 earlyprintk=xen" \
+    -device guest-loader,addr=0x47000000,initrd=rootfs.cpio
+
+In the above example the Xen hypervisor is loaded by the -kernel
+parameter and passed it's boot arguments via -append. The Dom0 guest
+is loaded into the areas of memory. Each blob will get
+`/chosen/module@<addr>` entry in the FDT to indicate it's location and
+size. Additional information can be passed with by using additional
+arguments.
+
+Currently the only supported machines which use FDT data to boot are
+the ARM and RiscV `virt` machines.
+
+Arguments
+^^^^^^^^^
+
+The full syntax of the guest-loader is::
+
+  -device guest-loader,addr=<addr>[,kernel=<file>,[bootargs=<args>]][,initrd=<file>]
+
+``addr=<addr>``
+  This is mandatory and indicates the start address of the blob.
+
+``kernel|initrd=<file>``
+  Indicates the filename of the kernel or initrd blob. Both blobs will
+  have the "multiboot,module" compatibility string as well as
+  "multiboot,kernel" or "multiboot,ramdisk" as appropriate.
+
+``bootargs=<args>``
+  This is an optional field for kernel blobs which will pass command
+  like via the `/chosen/module@<addr>/bootargs` node.
diff --git a/docs/system/index.rst b/docs/system/index.rst
index 625b494372..6ad9c93806 100644
--- a/docs/system/index.rst
+++ b/docs/system/index.rst
@@ -25,6 +25,8 @@ Contents:
    usb
    ivshmem
    linuxboot
+   generic-loader
+   guest-loader
    vnc-security
    tls
    gdb
diff --git a/docs/system/quickstart.rst b/docs/system/quickstart.rst
index 3a3acab5e7..681678c86e 100644
--- a/docs/system/quickstart.rst
+++ b/docs/system/quickstart.rst
@@ -11,3 +11,11 @@ Download and uncompress a PC hard disk image with Linux installed (e.g.
    |qemu_system| linux.img
 
 Linux should boot and give you a prompt.
+
+Users should be aware the above example elides a lot of the complexity
+of setting up a VM with x86_64 specific defaults and assumes the
+first non switch argument is a PC compatible disk image with a boot
+sector. For a non-x86 system where we emulate a broad range of machine
+types, the command lines are generally more explicit in defining the
+machine and boot behaviour. You will find more example command lines
+in the :ref:`system-targets-ref` section of the manual.
diff --git a/docs/system/targets.rst b/docs/system/targets.rst
index 75ed1087fd..9dcd95dd84 100644
--- a/docs/system/targets.rst
+++ b/docs/system/targets.rst
@@ -1,3 +1,5 @@
+.. _system-targets-ref:
+
 QEMU System Emulator Targets
 ============================