[Qemu-devel] [PATCH 05/13] xen: groundwork for xen support

[Gerd Hoffmann <kraxel@redhat.com>]

- configure script and build system changes.
- wind up new machine type.
- add -domid command line option.
- allow xenpv machines run without disk and kernel specified
  by adding a nodisk_ok field to QEMUMachine.
- detect xen being present.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 Makefile.target       |    8 +++
 configure             |   27 +++++++++
 hw/boards.h           |    3 +
 hw/xen.h              |   18 ++++++
 hw/xen_machine_pv.c   |  146 +++++++++++++++++++++++++++++++++++++++++++++++++
 target-i386/machine.c |    3 +
 vl.c                  |   15 +++++
 7 files changed, 220 insertions(+), 0 deletions(-)
 create mode 100644 hw/xen.h
 create mode 100644 hw/xen_machine_pv.c

diff --git a/Makefile.target b/Makefile.target
index 42162c3..13ee854 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -515,6 +515,14 @@ CPPFLAGS += $(CONFIG_VNC_TLS_CFLAGS)
 LIBS += $(CONFIG_VNC_TLS_LIBS)
 endif
 
+# xen backend driver support
+XEN_OBJS := xen_machine_pv.o
+ifeq ($(CONFIG_XEN), yes)
+  OBJS += $(XEN_OBJS)
+  LIBS += $(XEN_LIBS)
+  $(XEN_OBJS) : CFLAGS += -Wall -Wmissing-prototypes -Wstrict-prototypes
+endif
+
 # SCSI layer
 OBJS+= lsi53c895a.o esp.o
 
diff --git a/configure b/configure
index 74ce443..14689d2 100755
--- a/configure
+++ b/configure
@@ -109,6 +109,7 @@ curses="yes"
 aio="yes"
 nptl="yes"
 mixemu="no"
+xen="no"
 
 # OS specific
 targetos=`uname -s`
@@ -204,6 +205,7 @@ linux="yes"
 linux_user="yes"
 if [ "$cpu" = "i386" -o "$cpu" = "x86_64" ] ; then
     kqemu="yes"
+    xen="yes"
     audio_possible_drivers="$audio_possible_drivers fmod"
 fi
 ;;
@@ -287,6 +289,8 @@ for opt do
   ;;
   --disable-kqemu) kqemu="no"
   ;;
+  --disable-xen) xen="no"
+  ;;
   --disable-brlapi) brlapi="no"
   ;;
   --enable-profiler) profiler="yes"
@@ -425,6 +429,7 @@ echo "                           Available drivers: $audio_possible_drivers"
 echo "  --audio-card-list=LIST   set list of additional emulated audio cards"
 echo "                           Available cards: ac97 adlib cs4231a gus"
 echo "  --enable-mixemu          enable mixer emulation"
+echo "  --disable-xen            disable xen backend driver support"
 echo "  --disable-brlapi         disable BrlAPI"
 echo "  --disable-vnc-tls        disable TLS encryption for VNC server"
 echo "  --disable-curses         disable curses output"
@@ -686,6 +691,22 @@ else
 fi
 
 ##########################################
+# xen probe
+
+if test "$xen" = "yes" ; then
+cat > $TMPC <<EOF
+#include <xenctrl.h>
+#include <xs.h>
+int main(void) { xs_daemon_open; xc_interface_open; }
+EOF
+   if $cc $ARCH_CFLAGS -c -o $TMPO $TMPC -lxenstore -lxenctrl 2> /dev/null ; then
+      :
+   else
+      xen="no"
+   fi
+fi
+
+##########################################
 # SDL probe
 
 sdl_too_old=no
@@ -946,6 +967,7 @@ if test -n "$sparc_cpu"; then
     echo "Target Sparc Arch $sparc_cpu"
 fi
 echo "kqemu support     $kqemu"
+echo "xen support       $xen"
 echo "brlapi support    $brlapi"
 echo "Documentation     $build_docs"
 [ ! -z "$uname_release" ] && \
@@ -1203,6 +1225,11 @@ if test "$brlapi" = "yes" ; then
   echo "#define CONFIG_BRLAPI 1" >> $config_h
   echo "BRLAPI_LIBS=-lbrlapi" >> $config_mak
 fi
+if test "$xen" = "yes" ; then
+  echo "CONFIG_XEN=yes" >> $config_mak
+  echo "#define CONFIG_XEN 1" >> $config_h
+  echo "XEN_LIBS=-lxenstore -lxenctrl" >> $config_mak
+fi
 if test "$aio" = "yes" ; then
   echo "#define CONFIG_AIO 1" >> $config_h
 fi
diff --git a/hw/boards.h b/hw/boards.h
index e6dd198..9af9939 100644
--- a/hw/boards.h
+++ b/hw/boards.h
@@ -30,6 +30,9 @@ extern QEMUMachine bareetraxfs_machine;
 extern QEMUMachine pc_machine;
 extern QEMUMachine isapc_machine;
 
+/* xen_machine.c */
+extern QEMUMachine xenpv_machine;
+
 /* ppc.c */
 extern QEMUMachine prep_machine;
 extern QEMUMachine core99_machine;
diff --git a/hw/xen.h b/hw/xen.h
new file mode 100644
index 0000000..a772aad
--- /dev/null
+++ b/hw/xen.h
@@ -0,0 +1,18 @@
+#ifndef QEMU_XEN_H
+#define QEMU_XEN_H 1
+/*
+ * public xen header
+ *   stuff needed outside xen-*.c, i.e. interfaces to qemu.
+ *   must not depend on any xen headers being present in
+ *   /usr/include/xen, so it can be included unconditionally.
+ */
+
+/* xen-machine.c */
+extern int xen_domid;
+extern int xen_present;
+extern int xen_emulate;
+extern int xen_domainbuild;
+
+int xen_detect(void);
+
+#endif /* QEMU_XEN_H */
diff --git a/hw/xen_machine_pv.c b/hw/xen_machine_pv.c
new file mode 100644
index 0000000..05f0e67
--- /dev/null
+++ b/hw/xen_machine_pv.c
@@ -0,0 +1,146 @@
+/*
+ * QEMU Xen PV Machine
+ *
+ * Copyright (c) 2007,08 Red Hat
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "hw.h"
+#include "boards.h"
+
+#include <xenctrl.h>
+
+/* -------------------------------------------------------------------- */
+/* variables                                                            */
+
+int xen_domid;
+int xen_present = -1;
+int xen_emulate;
+int xen_domainbuild;
+
+/* -------------------------------------------------------------------- */
+/* initialization code                                                  */
+
+/*
+ * Figure the environment we are running in.
+ * Returns true when xen is present, false otherwise.
+ * Also checks whenever the domain specified via -domid
+ * exists (so we can attach) or whenever it must be created.
+ */
+int xen_detect(void)
+{
+    struct xc_dominfo info;
+    int xc, rc;
+
+    if (xen_present != -1)
+        goto out;
+
+    /* running on xen? (priviledged domain) */
+    xen_present = 0;
+    xc = xc_interface_open();
+    if (-1 == xc)
+        goto out;
+    xen_present = 1;
+
+    /* does the domain exist?  Or should we create one? */
+    rc = xc_domain_getinfo(xc, xen_domid, 1, &info);
+    if ((1 != rc) || (info.domid != xen_domid))
+        xen_domainbuild = 1;
+    close(xc);
+
+out:
+    return xen_present;
+}
+
+static int xen_init(void)
+{
+    if (!xen_domid) {
+	fprintf(stderr, "%s: no domid specified\n", __FUNCTION__);
+	return -1;
+    }
+
+    if (!xen_detect()) {
+        fprintf(stderr, "%s: emulating Xen\n", __FUNCTION__);
+        xen_emulate = 1;
+    }
+
+    return 0;
+}
+
+static int xen_init_pv(DisplayState *ds)
+{
+    int rc;
+
+    rc = xen_init();
+    if (rc < 0)
+        return rc;
+
+    return 0;
+}
+
+/* -------------------------------------------------------------------- */
+/* paravirtualized xen machine                                          */
+
+static void xenpv_init(ram_addr_t ram_size, int vga_ram_size,
+		       const char *boot_device, DisplayState *ds,
+		       const char *kernel_filename,
+		       const char *kernel_cmdline,
+		       const char *initrd_filename,
+		       const char *cpu_model)
+{
+    CPUState *env;
+    int rc;
+
+    rc = xen_init_pv(ds);
+    if (-1 == rc)
+        goto err;
+
+    if (xen_emulate) {
+        fprintf(stderr, "xen pv emulation not implemented yet\n");
+        goto err;
+    }
+    if (xen_domainbuild) {
+        fprintf(stderr, "xen pv domain creation not implemented yet\n");
+        goto err;
+    }
+
+    /* create dummy cpu, halted */
+    if (cpu_model == NULL) {
+#ifdef TARGET_X86_64
+        cpu_model = "qemu64";
+#else
+        cpu_model = "qemu32";
+#endif
+    }
+    env = cpu_init(cpu_model);
+    env->halted = 1;
+
+    return;
+
+err:
+    exit(1);
+}
+
+QEMUMachine xenpv_machine = {
+    .name = "xenpv",
+    .desc = "paravirtualized Xen machine",
+    .init = xenpv_init,
+    .nodisk_ok = 1,
+};
diff --git a/target-i386/machine.c b/target-i386/machine.c
index 91dbd55..98ece17 100644
--- a/target-i386/machine.c
+++ b/target-i386/machine.c
@@ -9,6 +9,9 @@ void register_machines(void)
 {
     qemu_register_machine(&pc_machine);
     qemu_register_machine(&isapc_machine);
+#ifdef CONFIG_XEN
+    qemu_register_machine(&xenpv_machine);
+#endif
 }
 
 static void cpu_put_seg(QEMUFile *f, SegmentCache *dt)
diff --git a/vl.c b/vl.c
index 3211507..ff94c6f 100644
--- a/vl.c
+++ b/vl.c
@@ -29,6 +29,7 @@
 #include "hw/audiodev.h"
 #include "hw/isa.h"
 #include "hw/baum.h"
+#include "hw/xen.h"
 #include "net.h"
 #include "console.h"
 #include "sysemu.h"
@@ -7780,6 +7781,9 @@ static void help(int exitcode)
            "-startdate      select initial date of the clock\n"
            "-icount [N|auto]\n"
            "                Enable virtual instruction counter with 2^N clock ticks per instruction\n"
+#ifdef CONFIG_XEN
+           "-domid          specify xen guest domain id\n"
+#endif
            "\n"
            "During emulation, the following keys are useful:\n"
            "ctrl-alt-f      toggle full screen\n"
@@ -7885,6 +7889,9 @@ enum {
     QEMU_OPTION_startdate,
     QEMU_OPTION_tb_size,
     QEMU_OPTION_icount,
+#ifdef CONFIG_XEN
+    QEMU_OPTION_domid,
+#endif
 };
 
 typedef struct QEMUOption {
@@ -7973,6 +7980,9 @@ const QEMUOption qemu_options[] = {
 #ifdef CONFIG_CURSES
     { "curses", 0, QEMU_OPTION_curses },
 #endif
+#ifdef CONFIG_XEN
+    { "domid", HAS_ARG, QEMU_OPTION_domid },
+#endif
 
     /* temporary options */
     { "usb", 0, QEMU_OPTION_usb },
@@ -8847,6 +8857,11 @@ int main(int argc, char **argv)
                     icount_time_shift = strtol(optarg, NULL, 0);
                 }
                 break;
+#ifdef CONFIG_XEN
+            case QEMU_OPTION_domid:
+                xen_domid = atoi(optarg);
+                break;
+#endif
             }
         }
     }
-- 
1.5.5.1