xen: blk & nic configuration via cmd line. (Gerd Hoffmann)

This patch makes qemu create backend and frontend device entries in
xenstore for devices configured on the command line.  It will use
qdisk and qnic backend names, so the qemu internal backends will
be used.

Disks can be created using -drive if=xen,file=...
Nics can be created using -net nic,macaddr=...

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7225 c046a42c-6fe2-441c-8c8c-71466251a162

Makefile.target

@@ -561,7 +561,7 @@ LIBS += $(CONFIG_BLUEZ_LIBS)
 endif
 
 # xen backend driver support
-XEN_OBJS := xen_machine_pv.o xen_backend.o
+XEN_OBJS := xen_machine_pv.o xen_backend.o xen_devconfig.o
 XEN_OBJS += xen_console.o xenfb.o xen_disk.o xen_nic.o
 ifeq ($(CONFIG_XEN), yes)
   OBJS += $(XEN_OBJS)

hw/xen_backend.c

@@ -45,6 +45,7 @@
 /* public */
 int xen_xc;
 struct xs_handle *xenstore = NULL;
+const char *xen_protocol;
 
 /* private */
 static TAILQ_HEAD(XenDeviceHead, XenDevice) xendevs = TAILQ_HEAD_INITIALIZER(xendevs);

hw/xen_backend.h

@@ -3,6 +3,8 @@
 
 #include "xen_common.h"
 #include "sysemu.h"
+#include "net.h"
+#include "block_int.h"
 
 /* ------------------------------------------------------------- */
 
@@ -56,6 +58,7 @@ struct XenDevice {
 /* variables */
 extern int xen_xc;
 extern struct xs_handle *xenstore;
+extern const char *xen_protocol;
 
 /* xenstore helper functions */
 int xenstore_write_str(const char *base, const char *node, const char *val);
@@ -93,4 +96,9 @@ extern struct XenDevOps xen_netdev_ops;       /* xen_nic.c         */
 
 void xen_init_display(int domid);
 
+/* configuration (aka xenbus setup) */
+void xen_config_cleanup(void);
+int xen_config_dev_blk(DriveInfo *disk);
+int xen_config_dev_nic(NICInfo *nic);
+
 #endif /* QEMU_HW_XEN_BACKEND_H */

hw/xen_devconfig.c

@@ -0,0 +1,142 @@
+#include "xen_backend.h"
+
+/* ------------------------------------------------------------- */
+
+struct xs_dirs {
+    char *xs_dir;
+    TAILQ_ENTRY(xs_dirs) list;
+};
+static TAILQ_HEAD(xs_dirs_head, xs_dirs) xs_cleanup = TAILQ_HEAD_INITIALIZER(xs_cleanup);
+
+static void xen_config_cleanup_dir(char *dir)
+{
+    struct xs_dirs *d;
+
+    d = qemu_malloc(sizeof(*d));
+    d->xs_dir = dir;
+    TAILQ_INSERT_TAIL(&xs_cleanup, d, list);
+}
+
+void xen_config_cleanup(void)
+{
+    struct xs_dirs *d;
+
+    TAILQ_FOREACH(d, &xs_cleanup, list) {
+	xs_rm(xenstore, 0, d->xs_dir);
+    }
+}
+
+/* ------------------------------------------------------------- */
+
+static int xen_config_dev_mkdir(char *dev, int p)
+{
+    struct xs_permissions perms[2] = {{
+            .id    = 0, /* set owner: dom0 */
+        },{
+            .id    = xen_domid,
+            .perms = p,
+        }};
+
+    if (!xs_mkdir(xenstore, 0, dev)) {
+	xen_be_printf(NULL, 0, "xs_mkdir %s: failed\n", dev);
+	return -1;
+    }
+    xen_config_cleanup_dir(qemu_strdup(dev));
+
+    if (!xs_set_permissions(xenstore, 0, dev, perms, 2)) {
+	xen_be_printf(NULL, 0, "xs_set_permissions %s: failed\n", dev);
+	return -1;
+    }
+    return 0;
+}
+
+static int xen_config_dev_dirs(const char *ftype, const char *btype, int vdev,
+			       char *fe, char *be, int len)
+{
+    char *dom;
+
+    dom = xs_get_domain_path(xenstore, xen_domid);
+    snprintf(fe, len, "%s/device/%s/%d", dom, ftype, vdev);
+    free(dom);
+
+    dom = xs_get_domain_path(xenstore, 0);
+    snprintf(be, len, "%s/backend/%s/%d/%d", dom, btype, xen_domid, vdev);
+    free(dom);
+
+    xen_config_dev_mkdir(fe, XS_PERM_READ | XS_PERM_WRITE);
+    xen_config_dev_mkdir(be, XS_PERM_READ);
+    return 0;
+}
+
+static int xen_config_dev_all(char *fe, char *be)
+{
+    /* frontend */
+    if (xen_protocol)
+        xenstore_write_str(fe, "protocol", xen_protocol);
+
+    xenstore_write_int(fe, "state",           XenbusStateInitialising);
+    xenstore_write_int(fe, "backend-id",      0);
+    xenstore_write_str(fe, "backend",         be);
+
+    /* backend */
+    xenstore_write_str(be, "domain",          qemu_name ? qemu_name : "no-name");
+    xenstore_write_int(be, "online",          1);
+    xenstore_write_int(be, "state",           XenbusStateInitialising);
+    xenstore_write_int(be, "frontend-id",     xen_domid);
+    xenstore_write_str(be, "frontend",        fe);
+
+    return 0;
+}
+
+/* ------------------------------------------------------------- */
+
+int xen_config_dev_blk(DriveInfo *disk)
+{
+    char fe[256], be[256];
+    int vdev = 202 * 256 + 16 * disk->unit;
+    int cdrom = disk->bdrv->type == BDRV_TYPE_CDROM;
+    const char *devtype = cdrom ? "cdrom" : "disk";
+    const char *mode    = cdrom ? "r"     : "w";
+
+    snprintf(disk->bdrv->device_name, sizeof(disk->bdrv->device_name),
+	     "xvd%c", 'a' + disk->unit);
+    xen_be_printf(NULL, 1, "config disk %d [%s]: %s\n",
+                  disk->unit, disk->bdrv->device_name, disk->bdrv->filename);
+    xen_config_dev_dirs("vbd", "qdisk", vdev, fe, be, sizeof(fe));
+
+    /* frontend */
+    xenstore_write_int(fe, "virtual-device",  vdev);
+    xenstore_write_str(fe, "device-type",     devtype);
+
+    /* backend */
+    xenstore_write_str(be, "dev",             disk->bdrv->device_name);
+    xenstore_write_str(be, "type",            "file");
+    xenstore_write_str(be, "params",          disk->bdrv->filename);
+    xenstore_write_str(be, "mode",            mode);
+
+    /* common stuff */
+    return xen_config_dev_all(fe, be);
+}
+
+int xen_config_dev_nic(NICInfo *nic)
+{
+    char fe[256], be[256];
+    char mac[20];
+
+    snprintf(mac, sizeof(mac), "%02x:%02x:%02x:%02x:%02x:%02x",
+	     nic->macaddr[0], nic->macaddr[1], nic->macaddr[2],
+	     nic->macaddr[3], nic->macaddr[4], nic->macaddr[5]);
+    xen_be_printf(NULL, 1, "config nic %d: mac=\"%s\"\n", nic->vlan->id, mac);
+    xen_config_dev_dirs("vif", "qnic", nic->vlan->id, fe, be, sizeof(fe));
+
+    /* frontend */
+    xenstore_write_int(fe, "handle",     nic->vlan->id);
+    xenstore_write_str(fe, "mac",        mac);
+
+    /* backend */
+    xenstore_write_int(be, "handle",     nic->vlan->id);
+    xenstore_write_str(be, "mac",        mac);
+
+    /* common stuff */
+    return xen_config_dev_all(fe, be);
+}

hw/xen_machine_pv.c

@@ -39,6 +39,7 @@ static void xen_init_pv(ram_addr_t ram_size, int vga_ram_size,
 			const char *cpu_model)
 {
     CPUState *env;
+    int i, index;
 
     /* Initialize a dummy CPU */
     if (cpu_model == NULL) {
@@ -62,6 +63,24 @@ static void xen_init_pv(ram_addr_t ram_size, int vga_ram_size,
     xen_be_register("qdisk", &xen_blkdev_ops);
     xen_be_register("qnic", &xen_netdev_ops);
 
+    /* configure disks */
+    for (i = 0; i < 16; i++) {
+        index = drive_get_index(IF_XEN, 0, i);
+        if (index == -1)
+            continue;
+        xen_config_dev_blk(drives_table + index);
+    }
+
+    /* configure nics */
+    for (i = 0; i < nb_nics; i++) {
+        if (!nd_table[i].model || 0 != strcmp(nd_table[i].model, "xen"))
+            continue;
+        xen_config_dev_nic(nd_table + i);
+    }
+
+    /* config cleanup hook */
+    atexit(xen_config_cleanup);
+
     /* setup framebuffer */
     xen_init_display(xen_domid);
 }