gdb + kvm調試內核

1.編譯內核
修改Makefile，修改成-O1 或者-O0
ifdef CONFIG_PROFILE_ALL_BRANCHES
KBUILD_CFLAGS += -O1 $(call cc-disable-warning,maybe-uninitialized,)
else
KBUILD_CFLAGS += -O1
endif

2. 修改虛擬機xml文件
   <domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>;
   ......
   </devices>
   <qemu:commandline>
   <qemu:arg value='-S'/>
   <qemu:arg value='-gdb'/>
   <qemu:arg value='tcp::1234'/>
   </qemu:commandline>
   </domain>

啓動虛擬機
id=balloon0,bus=pci.0,addr=0x9 -S -gdb tcp::1234 -msg timestamp=on

3. 在宿主機上建立目錄，拷貝須要調試的內核文件到該目錄下，如：
   vmlinuz-4.14.0-generic
   vmlinuz-4.14.0-generic: x86 boot sector

4.啓動gdb
gdb vmlinuz-4.14.0-generic
(gdb) target remote 127.0.0.1:1234
Remote debugging using 127.0.0.1:1234

編譯kvm
1.進入kvm所在的目錄
linux-4.14/arch/x86/kvm
2.執行編譯命令
make CONFIG_KVM=m CONFIG_INTEL_KVM=m -C /vms/kernel4.14/linux-4.14 M=$PWD modules
/vms/kernel4.14/linux-4.14 內核所在的路徑
M=$PWD kvm所在的路徑

進入內核代碼目路
make CONFIG_KVM=m CONFIG_INTEL_KVM=m -C /vms/kernel4.14/linux-4.14 M=/vms/kernel4.14/linux-4.14/arch/x86/kvm modules