Fix a wrong flag (--without-default-devices). Test the binary with oreboot/mainboard/sifive/hifive

.gitignore

@@ -0,0 +1,2 @@
+qemu/
+test/qemu-system-riscv64

README.qemu

@@ -1,8 +1,12 @@
 This qemu was create as follows:
-    git clone https://github.com/qemu/qemu && cd qemu 
-    git checkout v4.2.0-rc3
+    git clone https://github.com/qemu/qemu && cd qemu
+    # this is an old version, use the recent one
+    # git checkout v4.2.0-rc3
+
+    git checkout v5.1.0
+
     mkdir build-riscv64 && cd build-riscv64
-    # force useless shit off
+    # force useless shit off - the following applies when target os is Linux, see the configure script
 rminnich@xcpu:~/projects/oreboot/qemu$ git diff
 diff --git a/configure b/configure
 index 6099be1d84..b8376dce77 100755
@@ -20,9 +24,18 @@ index 6099be1d84..b8376dce77 100755
    supported_os="yes"
 -  libudev="yes"
 +  libudev="no"
-    ../configure --target-list=riscv64-softmmu --static --audio-drv-list=""  --without-default-devices --disable-vnc 
+    ../configure --target-list=riscv64-softmmu --static --audio-drv-list=""  --without-default-devices --disable-vnc
     make -j16
 
+The following problems were encountered when building on Ubuntu 18.04.
+- had to use use this patch as a workaround to a Sphinx-related problem
+which terminated the build:
+https://www.mail-archive.com/qemu-devel@nongnu.org/msg723079.html
+
+- make sure to install libmount-dev, libselinux1-dev on Ubuntu, or
+similar packages for other systems. Also see the part of build.sh that
+tweaks the automatically generate config-host.mak.
+
 qemu LICENSE
 
 The QEMU distribution includes both the QEMU emulator and

build.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+
+git clone https://github.com/qemu/qemu && cd qemu
+git checkout v5.1.0
+
+# Apply a patch as a workaround to fix Qemu Sphinx-related problem
+git apply ../fix_qemu_sphinx_warning.patch
+
+# Now tweak the build options for Linux target OS. We maintain a patch
+# for that purpose.
+git apply ../tweak_linux_config_options.patch
+
+echo 'Successfully applied the required patches. Configuring now...'
+# Most importantly, note '--static'
+mkdir build-riscv64 && cd build-riscv64
+
+../configure --target-list=riscv64-softmmu --static --audio-drv-list=""   --disable-vnc
+
+echo "Successfully configured. Building now..."
+# On my machine, configuration step did not collect all the dependencies
+# required to build Qemu. So manually appending them here, even if they
+# are present already.
+sudo apt install libblkid-dev libselinux1-dev uuid-dev libmount-dev
+awk -F '=' -i inplace '{ if ($1 == "GIO_LIBS") { print $0 " -lblkid -luuid" } else { print $0 } }' config-host.mak
+
+make -j4

fix_qemu_sphinx_warning.patch

@@ -0,0 +1,31 @@
+diff --git a/docs/qemu-option-trace.rst.inc b/docs/qemu-option-trace.rst.inc
+index 7e09773a9c..e79b0b43fc 100644
+--- a/docs/qemu-option-trace.rst.inc
++++ b/docs/qemu-option-trace.rst.inc
+@@ -1,7 +1,7 @@
+
+ Specify tracing options.
+
+-.. option:: [enable=]PATTERN
++.. option:: -trace [enable=]PATTERN
+
+   Immediately enable events matching *PATTERN*
+   (either event name or a globbing pattern).  This option is only
+@@ -11,7 +11,7 @@ Specify tracing options.
+
+   Use :option:`-trace help` to print a list of names of trace points.
+
+-.. option:: events=FILE
++.. option:: -trace events=FILE
+
+   Immediately enable events listed in *FILE*.
+   The file must contain one event name (as listed in the ``trace-events-all``
+@@ -19,7 +19,7 @@ Specify tracing options.
+   available if QEMU has been compiled with the ``simple``, ``log`` or
+   ``ftrace`` tracing backend.
+
+-.. option:: file=FILE
++.. option:: -trace file=FILE
+
+   Log output traces to *FILE*.
+   This option is only available if QEMU has been compiled with

notes.md

@@ -0,0 +1,28 @@
+~~We can't build softmmu-* targets with --static flag, here is a
+[thread](https://lists.gnu.org/archive/html/qemu-devel/2011-11/msg02878.html)
+from QEMU mailing list that shows why (and I have experienced more or
+less the same - qemu would just not build and complain about missing
+libraries). In other words, running programs which are not intended to
+be run in user mode is not possible with --static binaries. I have also
+found this
+[Debian wiki page](https://wiki.debian.org/RISC-V#Manual_qemu-user_installation)
+that talks about static qemu-riscv binaries,
+and they only mention linux-user target (not softmmu, and we need the
+latter).~~ Turns out it is still possible to do so (why - no idea, but it
+works and thank QEMU for that)
+
+- A *-linux-user target is for running programs in user mode, for
+example, it will run an example from test/usermode/data.
+
+The origial PR failed because device loader was not found. However, it
+used a flag --without-default-devices, or something like that, which
+could just disable that device.
+
+- [x] Try removing that flag. (Worked)
+
+Also anyway need to update QEMU to version 5.1.0, so all the builds
+should be executed with that version.
+
+I thought that using softmmut-* target requries that we also copy
+the qemu-img binary to usr/bin, but now seems like that is not a
+requirement with --static flag.

test/example_run.sh

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+./qemu-system-riscv64 -m 1g -machine sifive_u,start-in-flash=true -nographic -device loader,addr=0x20000000,file=softmmu/hifive -bios none -smp 4

test/notes.md

@@ -0,0 +1 @@
+run ./example_run.sh

test/softmmu/notes.md

@@ -0,0 +1,2 @@
+These binaries must be successfully run by the static qemu in order
+to close the PR.

test/usermode/notes.md

@@ -0,0 +1 @@
+This example was taken from u-root project.

tweak_linux_config_options.patch

@@ -0,0 +1,23 @@
+diff --git a/configure b/configure
+index 2acc4d1465..adbf541c2f 100755
+--- a/configure
++++ b/configure
+@@ -907,14 +907,14 @@ Haiku)
+   LIBS="-lposix_error_mapper -lnetwork -lbsd $LIBS"
+ ;;
+ Linux)
+-  audio_drv_list="try-pa oss"
+-  audio_possible_drivers="oss alsa sdl pa"
++  audio_drv_list=""
++  audio_possible_drivers=""
+   linux="yes"
+   linux_user="yes"
+-  kvm="yes"
++  kvm="no"
+   QEMU_INCLUDES="-isystem \$(SRC_PATH)/linux-headers -isystem $PWD/linux-headers $QEMU_INCLUDES"
+   supported_os="yes"
+-  libudev="yes"
++  libudev="no"
+ ;;
+ esac
+