Re: [RFC] Qemu powerpc work around

[Jerone Young <jyoung5@us.ibm.com>]

On Wed, 2008-02-13 at 09:29 +0200, Avi Kivity wrote:
> Jerone Young wrote:
> > So the recent code in qemu cvs has problem powerpc. So what I have done
> > is mainly work around this in the build system, by creating
> > ppcemb_kvm-sofmmu target. Along with this is a fake-exec.c that stubs
> > out the functions that are no longer defined (something done by Anthony
> > Liguori attempting to fix qemu_cvs). What do folks think about this
> > approach, for us all we really need is a qemu that is not built with tcg
> > dependency.
> >
> >   
> 
> Since a target in qemu is a cpu type, how the instructions are executed 
> (kvm, kqemu, dyngen, or tcg) shouldn't come into it.  Instead we can 
> have a --without-cpu-emulation or --no-tcg which would simply disable 
> those parts.

Actually this much much more sensible solution. So I took some time and
implemented it.

So on the qemu command line you use "--disable-cpu-emulation"

Signed-off-by: Jerone Young <jyoung5@us.ibm.com>

diff --git a/qemu/Makefile.target b/qemu/Makefile.target
--- a/qemu/Makefile.target
+++ b/qemu/Makefile.target
@@ -179,11 +179,17 @@ all: $(PROGS)
 
 #########################################################
 # cpu emulator library
-LIBOBJS=exec.o kqemu.o translate-all.o cpu-exec.o\
-        translate.o op.o host-utils.o
+LIBOBJS=exec.o kqemu.o cpu-exec.o host-utils.o
+
+ifneq ($(NO_CPU_EMULATION), 1)
+LIBOBJS+= translate-all.o translate.o op.o 
 # TCG code generator
 LIBOBJS+= tcg/tcg.o tcg/tcg-dyngen.o tcg/tcg-runtime.o
 CPPFLAGS+=-I$(SRC_PATH)/tcg -I$(SRC_PATH)/tcg/$(ARCH)
+else
+LIBOBJS+= fake-exec.o
+endif
+
 ifeq ($(USE_KVM), 1)
 LIBOBJS+=qemu-kvm.o
 endif
diff --git a/qemu/configure b/qemu/configure
--- a/qemu/configure
+++ b/qemu/configure
@@ -110,6 +110,7 @@ darwin_user="no"
 darwin_user="no"
 build_docs="no"
 uname_release=""
+cpu_emulation="yes"
 
 # OS specific
 targetos=`uname -s`
@@ -339,6 +340,8 @@ for opt do
   ;;
   --disable-werror) werror="no"
   ;;
+  --disable-cpu-emulation) cpu_emulation="no" 
+  ;;
   *) echo "ERROR: unknown option $opt"; exit 1
   ;;
   esac
@@ -770,6 +773,7 @@ fi
 fi
 echo "kqemu support     $kqemu"
 echo "kvm support       $kvm"
+echo "CPU emulation     $cpu_emulation"
 echo "Documentation     $build_docs"
 [ ! -z "$uname_release" ] && \
 echo "uname -r          $uname_release"
@@ -1094,12 +1098,20 @@ interp_prefix1=`echo "$interp_prefix" | 
 interp_prefix1=`echo "$interp_prefix" | sed "s/%M/$target_cpu/g"`
 echo "#define CONFIG_QEMU_PREFIX \"$interp_prefix1\"" >> $config_h
 
+disable_cpu_emulation() {
+  if test $cpu_emulation = "no"; then
+    echo "#define NO_CPU_EMULATION 1" >> $config_h
+    echo "NO_CPU_EMULATION=1" >> $config_mak
+  fi
+}
+
 configure_kvm() {
   if test $kvm = "yes" -a "$target_softmmu" = "yes" -a \
           \( "$cpu" = "i386" -o "$cpu" = "x86_64" -o "$cpu" = "ia64" -o "$cpu" = "powerpc" \); then
     echo "#define USE_KVM 1" >> $config_h
     echo "USE_KVM=1" >> $config_mak
     echo "CONFIG_KVM_KERNEL_INC=$kernel_path/include" >> $config_mak
+    disable_cpu_emulation 
   fi
 }
 
diff --git a/qemu/exec.c b/qemu/exec.c
--- a/qemu/exec.c
+++ b/qemu/exec.c
@@ -35,7 +35,11 @@
 
 #include "cpu.h"
 #include "exec-all.h"
+
+#if !defined(NO_CPU_EMULATION)
 #include "tcg-target.h"
+#endif
+
 #include "qemu-kvm.h"
 #if defined(CONFIG_USER_ONLY)
 #include <qemu.h>
diff --git a/qemu/fake-exec.c b/qemu/fake-exec.c
new file mode 100644
--- /dev/null
+++ b/qemu/fake-exec.c
@@ -0,0 +1,62 @@
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include "cpu.h"
+#include "exec-all.h"
+
+int code_copy_enabled = 0;
+
+void cpu_dump_state (CPUState *env, FILE *f,
+                     int (*cpu_fprintf)(FILE *f, const char *fmt, ...),
+                     int flags)
+{
+}
+
+void ppc_cpu_list (FILE *f, int (*cpu_fprintf)(FILE *f, const char *fmt, ...))
+{
+}
+
+void cpu_dump_statistics (CPUState *env, FILE*f,
+                          int (*cpu_fprintf)(FILE *f, const char *fmt, ...),
+                          int flags)
+{
+}
+
+unsigned long code_gen_max_block_size(void)
+{
+    return 32;
+}
+
+void cpu_gen_init(void)
+{
+}
+
+int cpu_restore_state(TranslationBlock *tb,
+                      CPUState *env, unsigned long searched_pc,
+                      void *puc)
+
+{
+    return 0;
+}
+
+int cpu_ppc_gen_code(CPUState *env, TranslationBlock *tb, int *gen_code_size_ptr)
+{
+    return 0;
+}
+
+const ppc_def_t *cpu_ppc_find_by_name (const unsigned char *name)
+{
+    return NULL;
+}
+
+int cpu_ppc_register_internal (CPUPPCState *env, const ppc_def_t *def)
+{
+    return 0;
+}
+
+void flush_icache_range(unsigned long start, unsigned long stop)
+{
+}



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