Hi, When I compile xen with the latest commit in RHEL 6.7, it failed when make tools. Errors showed when running edk2 build for OvmfPkgX64. Bisected and this error occurred from commit 8c8b6fb02342f7aa78e611a5f0f63dcf8fbf48f2. commit 8c8b6fb02342f7aa78e611a5f0f63dcf8fbf48f2 Author: Wei Liu > Date: Tue Sep 6 12:54:47 2016 +0100 Config.mk: update OVMF commit Signed-off-by: Wei Liu wei.liu2@citrix.com We have updated OVMF to the latest master and cleaned everything before rebuilding. Steps: make clean make xen -j8 ./configure --enable-ovmf make tools -j8 Then the error occurred. ......................................................................................................................................................... make_tools.log: ...... /home/www/builds_xen_unstable/xen-src-8c8b6fb0-20160912/tools/firmware/ovmf-dir-remote/Build/OvmfX64/DEBUG_GCC44/X64/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib/OUTPUT/X64/ExceptionHandlerAsm.iii:173: error: invalid combination of opcode and operands /home/www/builds_xen_unstable/xen-src-8c8b6fb0-20160912/tools/firmware/ovmf-dir-remote/Build/OvmfX64/DEBUG_GCC44/X64/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib/OUTPUT/X64/ExceptionHandlerAsm.iii:175: error: invalid combination of opcode and operands /home/www/builds_xen_unstable/xen-src-8c8b6fb0-20160912/tools/firmware/ovmf-dir-remote/Build/OvmfX64/DEBUG_GCC44/X64/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib/OUTPUT/X64/ExceptionHandlerAsm.iii:177: error: invalid combination of opcode and operands /home/www/builds_xen_unstable/xen-src-8c8b6fb0-20160912/tools/firmware/ovmf-dir-remote/Build/OvmfX64/DEBUG_GCC44/X64/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib/OUTPUT/X64/ExceptionHandlerAsm.iii:179: error: invalid combination of opcode and operands /home/www/builds_xen_unstable/xen-src-8c8b6fb0-20160912/tools/firmware/ovmf-dir-remote/Build/OvmfX64/DEBUG_GCC44/X64/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib/OUTPUT/X64/ExceptionHandlerAsm.iii:313: error: invalid combination of opcode and operands /home/www/builds_xen_unstable/xen-src-8c8b6fb0-20160912/tools/firmware/ovmf-dir-remote/Build/OvmfX64/DEBUG_GCC44/X64/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib/OUTPUT/X64/ExceptionHandlerAsm.iii:315: error: invalid combination of opcode and operands make[7]: Leaving directory `/home/www/builds_xen_unstable/xen-src-8c8b6fb0-20160912/tools/firmware/ovmf-dir-remote/Build/OvmfX64/DEBUG_GCC44/X64/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib' make[7]: *** [/home/www/builds_xen_unstable/xen-src-8c8b6fb0-20160912/tools/firmware/ovmf-dir-remote/Build/OvmfX64/DEBUG_GCC44/X64/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib/OUTPUT/X64/ExceptionHandlerAsm.obj] Error 1 build.py... : error 7000: Failed to execute command make tbuild [/home/www/builds_xen_unstable/xen-src-8c8b6fb0-20160912/tools/firmware/ovmf-dir-remote/Build/OvmfX64/DEBUG_GCC44/X64/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib] build.py... : error F002: Failed to build module /home/www/builds_xen_unstable/xen-src-8c8b6fb0-20160912/tools/firmware/ovmf-dir-remote/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.inf [X64, GCC44, DEBUG] - Failed - Best Regards, Fan Chen