LoongArch: KVM: Enable kvm config and add the makefile

Enable LoongArch kvm config and add the makefile to support build kvm
module.

Reviewed-by: Bibo Mao <maobibo@loongson.cn>
Tested-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/Kbuild

@@ -3,5 +3,7 @@ obj-y += mm/
 obj-y += net/
 obj-y += vdso/
 
+obj-$(CONFIG_KVM) += kvm/
+
 # for cleaning
 subdir- += boot

arch/loongarch/Kconfig

@@ -129,6 +129,7 @@ config LOONGARCH
 	select HAVE_KPROBES
 	select HAVE_KPROBES_ON_FTRACE
 	select HAVE_KRETPROBES
+	select HAVE_KVM
 	select HAVE_MOD_ARCH_SPECIFIC
 	select HAVE_NMI
 	select HAVE_PCI
@@ -263,6 +264,9 @@ config AS_HAS_LASX_EXTENSION
 config AS_HAS_LBT_EXTENSION
 	def_bool $(as-instr,movscr2gr \$a0$(comma)\$scr0)
 
+config AS_HAS_LVZ_EXTENSION
+	def_bool $(as-instr,hvcl 0)
+
 menu "Kernel type and options"
 
 source "kernel/Kconfig.hz"
@@ -676,3 +680,5 @@ source "kernel/power/Kconfig"
 source "drivers/acpi/Kconfig"
 
 endmenu
+
+source "arch/loongarch/kvm/Kconfig"

arch/loongarch/configs/loongson3_defconfig

@@ -66,6 +66,8 @@ CONFIG_EFI_ZBOOT=y
 CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER=y
 CONFIG_EFI_CAPSULE_LOADER=m
 CONFIG_EFI_TEST=m
+CONFIG_VIRTUALIZATION=y
+CONFIG_KVM=m
 CONFIG_JUMP_LABEL=y
 CONFIG_MODULES=y
 CONFIG_MODULE_FORCE_LOAD=y

arch/loongarch/kvm/Kconfig

@@ -0,0 +1,40 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# KVM configuration
+#
+
+source "virt/kvm/Kconfig"
+
+menuconfig VIRTUALIZATION
+	bool "Virtualization"
+	help
+	  Say Y here to get to see options for using your Linux host to run
+	  other operating systems inside virtual machines (guests).
+	  This option alone does not add any kernel code.
+
+	  If you say N, all options in this submenu will be skipped and
+	  disabled.
+
+if VIRTUALIZATION
+
+config KVM
+	tristate "Kernel-based Virtual Machine (KVM) support"
+	depends on AS_HAS_LVZ_EXTENSION
+	depends on HAVE_KVM
+	select HAVE_KVM_DIRTY_RING_ACQ_REL
+	select HAVE_KVM_EVENTFD
+	select HAVE_KVM_VCPU_ASYNC_IOCTL
+	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
+	select KVM_GENERIC_HARDWARE_ENABLING
+	select KVM_MMIO
+	select KVM_XFER_TO_GUEST_WORK
+	select MMU_NOTIFIER
+	select PREEMPT_NOTIFIERS
+	help
+	  Support hosting virtualized guest machines using
+	  hardware virtualization extensions. You will need
+	  a processor equipped with virtualization extensions.
+
+	  If unsure, say N.
+
+endif # VIRTUALIZATION

arch/loongarch/kvm/Makefile

@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for LoongArch KVM support
+#
+
+ccflags-y += -I $(srctree)/$(src)
+
+include $(srctree)/virt/kvm/Makefile.kvm
+
+obj-$(CONFIG_KVM) += kvm.o
+
+kvm-y += exit.o
+kvm-y += interrupt.o
+kvm-y += main.o
+kvm-y += mmu.o
+kvm-y += switch.o
+kvm-y += timer.o
+kvm-y += tlb.o
+kvm-y += vcpu.o
+kvm-y += vm.o
+
+CFLAGS_exit.o	+= $(call cc-option,-Wno-override-init,)