new file mode 100644
@@ -0,0 +1,41 @@
+:orphan:
+
+==========================================
+loongson3 virt generic platform (``virt``)
+==========================================
+
+The ``virt`` machine use gpex host bridge, and there are some
+emulated devices on virt board, such as loongson7a RTC device,
+IOAPIC device, ACPI device and so on.
+
+Supported devices
+-----------------
+
+The ``virt`` machine supports:
+- Gpex host bridge
+- Ls7a RTC device
+- Ls7a IOAPIC device
+- Ls7a ACPI device
+- Fw_cfg device
+- PCI/PCIe devices
+- Memory device
+- CPU device. Type: Loongson-3A5000.
+
+CPU and machine Type
+--------------------
+
+The ``qemu-system-loongarch64`` provides emulation for virt
+machine. You can specify the machine type ``virt`` and
+cpu type ``Loongson-3A5000``.
+
+Boot options
+------------
+
+Now the ``virt`` machine can run test program in ELF format and the
+method of compiling is in target/loongarch/README.
+
+.. code-block:: bash
+
+ $ qemu-system-loongarch64 -machine virt -m 4G -cpu Loongson-3A5000 \
+ -smp 1 -kernel hello -monitor none -display none \
+ -chardev file,path=hello.out,id=output -serial chardev:output
@@ -1122,6 +1122,14 @@ F: include/hw/net/lasi_82596.h
F: include/hw/pci-host/dino.h
F: pc-bios/hppa-firmware.img
+LoongArch Machines
+------------------
+Virt
+M: Xiaojuan Yang <yangxiaojuan@loongson.cn>
+M: Song Gao <gaosong@loongson.cn>
+S: Maintained
+F: docs/system/loongarch/loongson3.rst
+
M68K Machines
-------------
an5206
@@ -8,3 +8,57 @@
We can get the latest loongarch documents at https://github.com/loongson/LoongArch-Documentation/tags.
+
+- System emulation
+
+ Mainly emulate a virt 3A5000 board and ls7a bridge that is not exactly the same as the host.
+ 3A5000 support multiple interrupt cascading while here we just emulate the extioi interrupt
+ cascading. LS7A1000 host bridge support multiple devices, such as sata, gmac, uart, rtc
+ and so on. But we just realize the rtc. Others use the qemu common devices. It does not affect
+ the general use. We also introduced the emulation of devices at docs/system/loongarch/loongson3.rst.
+
+ This version only supports running binary files in ELF format, and does not depend on BIOS and kernel file.
+ You can compile the test program with 'make & make check-tcg' and run the test case with the following command:
+
+ 1. Install LoongArch cross-tools on X86 machines.
+
+ Download cross-tools.
+
+ wget https://github.com/loongson/build-tools/releases/latest/download/loongarch64-clfs-20211202-cross-tools.tar.xz
+
+ tar -vxf loongarch64-clfs-20211202-cross-tools.tar.xz -C /opt
+
+ Config cross-tools env.
+
+ . setenv.sh
+
+ setenv.sh:
+
+ #!/bin/sh
+ set -x
+ CC_PREFIX=/opt/cross-tools
+
+ export PATH=$CC_PREFIX/bin:$PATH
+ export LD_LIBRARY_PATH=$CC_PREFIX/lib:$LD_LIBRARY_PATH
+ export LD_LIBRARY_PATH=$CC_PREFIX/loongarch64-unknown-linux-gnu/lib/:$LD_LIBRARY_PATH
+ set +x
+
+ 2. Test tests/tcg/multiarch.
+
+ ./configure --disable-rdma --disable-pvrdma --prefix=/usr \
+ --target-list="loongarch64-softmmu" \
+ --disable-libiscsi --disable-libnfs --disable-libpmem \
+ --disable-glusterfs --enable-libusb --enable-usb-redir \
+ --disable-opengl --disable-xen --enable-spice --disable-werror \
+ --enable-debug --disable-capstone --disable-kvm --enable-profiler
+
+ cd build/
+
+ make && make check-tcg
+
+ or
+
+ ./build/qemu-system-loongarch64 -machine virt -m 4G -cpu Loongson-3A5000 -smp 1 -kernel build/tests/tcg/loongarch64-softmmu/hello -monitor none -display none -chardev file,path=hello.out,id=output -serial chardev:output
+
+- Note.
+ We can get the latest LoongArch documents or LoongArch tools at https://github.com/loongson/