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-rw-r--r--docs/system/i386/xen.rst76
-rw-r--r--docs/system/loongarch/virt.rst (renamed from docs/system/loongarch/loongson3.rst)97
-rw-r--r--docs/system/target-i386.rst1
3 files changed, 115 insertions, 59 deletions
diff --git a/docs/system/i386/xen.rst b/docs/system/i386/xen.rst
new file mode 100644
index 0000000000..a00523b492
--- /dev/null
+++ b/docs/system/i386/xen.rst
@@ -0,0 +1,76 @@
+Xen HVM guest support
+=====================
+
+
+Description
+-----------
+
+KVM has support for hosting Xen guests, intercepting Xen hypercalls and event
+channel (Xen PV interrupt) delivery. This allows guests which expect to be
+run under Xen to be hosted in QEMU under Linux/KVM instead.
+
+Setup
+-----
+
+Xen mode is enabled by setting the ``xen-version`` property of the KVM
+accelerator, for example for Xen 4.10:
+
+.. parsed-literal::
+
+  |qemu_system| --accel kvm,xen-version=0x4000a
+
+Additionally, virtual APIC support can be advertised to the guest through the
+``xen-vapic`` CPU flag:
+
+.. parsed-literal::
+
+  |qemu_system| --accel kvm,xen-version=0x4000a --cpu host,+xen_vapic
+
+When Xen support is enabled, QEMU changes hypervisor identification (CPUID
+0x40000000..0x4000000A) to Xen. The KVM identification and features are not
+advertised to a Xen guest. If Hyper-V is also enabled, the Xen identification
+moves to leaves 0x40000100..0x4000010A.
+
+The Xen platform device is enabled automatically for a Xen guest. This allows
+a guest to unplug all emulated devices, in order to use Xen PV block and network
+drivers instead. Note that until the Xen PV device back ends are enabled to work
+with Xen mode in QEMU, that is unlikely to cause significant joy. Linux guests
+can be dissuaded from this by adding 'xen_emul_unplug=never' on their command
+line, and it can also be noted that AHCI disk controllers are exempt from being
+unplugged, as are passthrough VFIO PCI devices.
+
+Properties
+----------
+
+The following properties exist on the KVM accelerator object:
+
+``xen-version``
+  This property contains the Xen version in ``XENVER_version`` form, with the
+  major version in the top 16 bits and the minor version in the low 16 bits.
+  Setting this property enables the Xen guest support.
+
+``xen-evtchn-max-pirq``
+  Xen PIRQs represent an emulated physical interrupt, either GSI or MSI, which
+  can be routed to an event channel instead of to the emulated I/O or local
+  APIC. By default, QEMU permits only 256 PIRQs because this allows maximum
+  compatibility with 32-bit MSI where the higher bits of the PIRQ# would need
+  to be in the upper 64 bits of the MSI message. For guests with large numbers
+  of PCI devices (and none which are limited to 32-bit addressing) it may be
+  desirable to increase this value.
+
+``xen-gnttab-max-frames``
+  Xen grant tables are the means by which a Xen guest grants access to its
+  memory for PV back ends (disk, network, etc.). Since QEMU only supports v1
+  grant tables which are 8 bytes in size, each page (each frame) of the grant
+  table can reference 512 pages of guest memory. The default number of frames
+  is 64, allowing for 32768 pages of guest memory to be accessed by PV backends
+  through simultaneous grants. For guests with large numbers of PV devices and
+  high throughput, it may be desirable to increase this value.
+
+OS requirements
+---------------
+
+The minimal Xen support in the KVM accelerator requires the host to be running
+Linux v5.12 or newer. Later versions add optimisations: Linux v5.17 added
+acceleration of interrupt delivery via the Xen PIRQ mechanism, and Linux v5.19
+accelerated Xen PV timers and inter-processor interrupts (IPIs).
diff --git a/docs/system/loongarch/loongson3.rst b/docs/system/loongarch/virt.rst
index 489ea20f8f..c37268b404 100644
--- a/docs/system/loongarch/loongson3.rst
+++ b/docs/system/loongarch/virt.rst
@@ -19,14 +19,14 @@ The ``virt`` machine supports:
 - Fw_cfg device
 - PCI/PCIe devices
 - Memory device
-- CPU device. Type: la464-loongarch-cpu.
+- CPU device. Type: la464.
 
 CPU and machine Type
 --------------------
 
 The ``qemu-system-loongarch64`` provides emulation for virt
 machine. You can specify the machine type ``virt`` and
-cpu type ``la464-loongarch-cpu``.
+cpu type ``la464``.
 
 Boot options
 ------------
@@ -35,95 +35,74 @@ We can boot the LoongArch virt machine by specifying the uefi bios,
 initrd, and linux kernel. And those source codes and binary files
 can be accessed by following steps.
 
-(1) booting command:
+(1) Build qemu-system-loongarch64:
 
 .. code-block:: bash
 
-  $ qemu-system-loongarch64 -machine virt -m 4G -cpu la464-loongarch-cpu \
-      -smp 1 -bios QEMU_EFI.fd -kernel vmlinuz.efi -initrd initrd.img \
-      -append "root=/dev/ram rdinit=/sbin/init console=ttyS0,115200" \
-      --nographic
-
-Note: The running speed may be a little slow, as the performance of our
-qemu and uefi bios is not perfect, and it is being fixed.
-
-(2) cross compiler tools:
-
-.. code-block:: bash
-
-  wget https://github.com/loongson/build-tools/releases/download/ \
-  2022.05.29/loongarch64-clfs-5.0-cross-tools-gcc-full.tar.xz
-
-  tar -vxf loongarch64-clfs-5.0-cross-tools-gcc-full.tar.xz
-
-(3) qemu compile configure option:
-
-.. code-block:: bash
-
-  ./configure --disable-rdma --disable-pvrdma --prefix=usr \
+  ./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 \
               --enable-debug --disable-capstone --disable-kvm \
               --enable-profiler
-  make
+  make -j8
 
-(4) uefi bios source code and compile method:
+(2) Set cross tools:
 
 .. code-block:: bash
 
-  git clone https://github.com/loongson/edk2-LoongarchVirt.git
-
-  cd edk2-LoongarchVirt
-
-  git submodule update --init
-
-  export PATH=$YOUR_COMPILER_PATH/bin:$PATH
-
-  export WORKSPACE=`pwd`
+  wget https://github.com/loongson/build-tools/releases/download/2022.09.06/loongarch64-clfs-6.3-cross-tools-gcc-glibc.tar.xz
 
-  export PACKAGES_PATH=$WORKSPACE/edk2-LoongarchVirt
+  tar -vxf loongarch64-clfs-6.3-cross-tools-gcc-glibc.tar.xz  -C /opt
 
-  export GCC5_LOONGARCH64_PREFIX=loongarch64-unknown-linux-gnu-
+  export PATH=/opt/cross-tools/bin:$PATH
+  export LD_LIBRARY_PATH=/opt/cross-tools/lib:$LD_LIBRARY_PATH
+  export LD_LIBRARY_PATH=/opt/cross-tools/loongarch64-unknown-linux-gnu/lib/:$LD_LIBRARY_PATH
 
-  edk2-LoongarchVirt/edksetup.sh
+Note: You need get the latest cross-tools at https://github.com/loongson/build-tools
 
-  make -C edk2-LoongarchVirt/BaseTools
+(3) Build BIOS:
 
-  build --buildtarget=DEBUG --tagname=GCC5 --arch=LOONGARCH64  --platform=OvmfPkg/LoongArchQemu/Loongson.dsc
+    See: https://github.com/tianocore/edk2-platforms/tree/master/Platform/Loongson/LoongArchQemuPkg#readme
 
-  build --buildtarget=RELEASE --tagname=GCC5 --arch=LOONGARCH64  --platform=OvmfPkg/LoongArchQemu/Loongson.dsc
+Note: To build the release version of the bios,  set --buildtarget=RELEASE,
+      the bios file path:  Build/LoongArchQemu/RELEASE_GCC5/FV/QEMU_EFI.fd
 
-The efi binary file path:
-
-  Build/LoongArchQemu/DEBUG_GCC5/FV/QEMU_EFI.fd
-
-  Build/LoongArchQemu/RELEASE_GCC5/FV/QEMU_EFI.fd
-
-(5) linux kernel source code and compile method:
+(4) Build kernel:
 
 .. code-block:: bash
 
   git clone https://github.com/loongson/linux.git
 
-  export PATH=$YOUR_COMPILER_PATH/bin:$PATH
-
-  export LD_LIBRARY_PATH=$YOUR_COMPILER_PATH/lib:$LD_LIBRARY_PATH
+  cd linux
 
-  export LD_LIBRARY_PATH=$YOUR_COMPILER_PATH/loongarch64-unknown-linux-gnu/lib/:$LD_LIBRARY_PATH
+  git checkout loongarch-next
 
   make ARCH=loongarch CROSS_COMPILE=loongarch64-unknown-linux-gnu- loongson3_defconfig
 
-  make ARCH=loongarch CROSS_COMPILE=loongarch64-unknown-linux-gnu-
-
-  make ARCH=loongarch CROSS_COMPILE=loongarch64-unknown-linux-gnu- install
-
-  make ARCH=loongarch CROSS_COMPILE=loongarch64-unknown-linux-gnu- modules_install
+  make ARCH=loongarch CROSS_COMPILE=loongarch64-unknown-linux-gnu- -j32
 
 Note: The branch of linux source code is loongarch-next.
+      the kernel file: arch/loongarch/boot/vmlinuz.efi
 
-(6) initrd file:
+(5) Get initrd:
 
   You can use busybox tool and the linux modules to make a initrd file. Or you can access the
   binary files: https://github.com/yangxiaojuan-loongson/qemu-binary
+
+.. code-block:: bash
+
+  git clone https://github.com/yangxiaojuan-loongson/qemu-binary
+
+Note: the initrd file is ramdisk
+
+(6) Booting LoongArch:
+
+.. code-block:: bash
+
+  $ ./build/qemu-system-loongarch64 -machine virt -m 4G -cpu la464 \
+      -smp 1 -bios QEMU_EFI.fd -kernel vmlinuz.efi -initrd ramdisk \
+      -serial stdio   -monitor telnet:localhost:4495,server,nowait \
+      -append "root=/dev/ram rdinit=/sbin/init console=ttyS0,115200" \
+      --nographic
diff --git a/docs/system/target-i386.rst b/docs/system/target-i386.rst
index e64c013077..77c2f3b979 100644
--- a/docs/system/target-i386.rst
+++ b/docs/system/target-i386.rst
@@ -27,6 +27,7 @@ Architectural features
 
    i386/cpu
    i386/hyperv
+   i386/xen
    i386/kvm-pv
    i386/sgx
    i386/amd-memory-encryption