Gerd Hoffmann wrote:
This patch adds infrastructure for xen backend drivers living in qemu,
so drivers don't need to implement common stuff on their own. It's
mostly xenbus management stuff: some functions to access xentore,
setting up xenstore watches, callbacks on device discovery and state
changes, handle event channel, ...
Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
---
Makefile.target | 2 +-
hw/xen_backend.c | 691 +++++++++++++++++++++++++++++++++++++++++++++++++++
hw/xen_backend.h | 86 +++++++
hw/xen_common.h | 34 +++
hw/xen_machine_pv.c | 8 +-
5 files changed, 819 insertions(+), 2 deletions(-)
create mode 100644 hw/xen_backend.c
create mode 100644 hw/xen_backend.h
create mode 100644 hw/xen_common.h
diff --git a/Makefile.target b/Makefile.target
index 1cad75e..5d9dfc7 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -558,7 +558,7 @@ LIBS += $(CONFIG_BLUEZ_LIBS)
endif
# xen backend driver support
-XEN_OBJS := xen_machine_pv.o
+XEN_OBJS := xen_machine_pv.o xen_backend.o
ifeq ($(CONFIG_XEN), yes)
OBJS += $(XEN_OBJS)
LIBS += $(XEN_LIBS)
diff --git a/hw/xen_backend.c b/hw/xen_backend.c
new file mode 100644
index 0000000..b13c3f9
--- /dev/null
+++ b/hw/xen_backend.c
@@ -0,0 +1,691 @@
+/*
+ * xen backend driver infrastructure
+ * (c) 2008 Gerd Hoffmann <kraxel@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; under version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/*
+ * TODO: add some xenbus / xenstore concepts overview here.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <sys/signal.h>
+
+#include <xs.h>
+#include <xenctrl.h>
+#include <xen/grant_table.h>
+
+#include "hw.h"
+#include "qemu-char.h"
+#include "xen_backend.h"
+
+/* ------------------------------------------------------------- */
+
+/* public */
+int xen_xc;
+struct xs_handle *xenstore = NULL;
+
+/* private */
+static TAILQ_HEAD(XenDeviceHead, XenDevice) xendevs =
TAILQ_HEAD_INITIALIZER(xendevs);
+static int debug = 0;
Would be better to have all of this in a structure that had a single
static instance. Would be even better if you could avoid requiring the
static instance.
+/* ------------------------------------------------------------- */
+
+int xenstore_write_str(const char *base, const char *node, const char *val)
+{
+ char abspath[XEN_BUFSIZE];
+
+ snprintf(abspath, sizeof(abspath), "%s/%s", base, node);
+ if (!xs_write(xenstore, 0, abspath, val, strlen(val)))
+ return -1;
+ return 0;
+}
+
+char *xenstore_read_str(const char *base, const char *node)
+{
+ char abspath[XEN_BUFSIZE];
+ unsigned int len;
+
+ snprintf(abspath, sizeof(abspath), "%s/%s", base, node);
+ return xs_read(xenstore, 0, abspath, &len);
xs_read() is a xenstore API, it's returning malloc()'d memory.
+}
+
+int xenstore_write_int(const char *base, const char *node, int ival)
+{
+ char val[32];
+
+ snprintf(val, sizeof(val), "%d", ival);
+ return xenstore_write_str(base, node, val);
+}
+
+int xenstore_read_int(const char *base, const char *node, int *ival)
+{
+ char *val;
+ int rc = -1;
+
+ val = xenstore_read_str(base, node);
+ if (val && 1 == sscanf(val, "%d", ival))
+ rc = 0;
+ qemu_free(val);
And here you're free()'ing with qemu_free.
+/*
+ * get xen backend device, allocate a new one if it doesn't exist.
+ */
+static struct XenDevice *xen_be_get_xendev(const char *type, int dom, int dev,
+ struct XenDevOps *ops)
+{
+ struct XenDevice *xendev;
+ char *dom0;
+
+ xendev = xen_be_find_xendev(type, dom, dev);
+ if (xendev)
+ return xendev;
+
+ /* init new xendev */
+ xendev = qemu_mallocz(ops->size);
+ if (!xendev)
+ return NULL;
No need to check malloc failures.
+
+ /* look for backends */
+ dev = xs_directory(xenstore, 0, path, &cdev);
+ if (!dev)
+ return 0;
+ for (j = 0; j < cdev; j++) {
+ xendev = xen_be_get_xendev(type, dom, atoi(dev[j]), ops);
+ if (xendev == NULL)
+ continue;
+ xen_be_check_state(xendev);
+ }
+ qemu_free(dev);
Mixing qemu_free() with malloc'd memory.
+static void xenstore_update_be(char *watch, char *type, int dom,
+ struct XenDevOps *ops)
+{
+ struct XenDevice *xendev;
+ char path[XEN_BUFSIZE], *dom0;
+ unsigned int len, dev;
+
+ dom0 = xs_get_domain_path(xenstore, 0);
+ len = snprintf(path, sizeof(path), "%s/backend/%s/%d", dom0, type, dom);
+ free(dom0);
+ if (0 != strncmp(path, watch, len))
+ return;
+ if (2 != sscanf(watch+len, "/%u/%255s", &dev, path)) {
+ strcpy(path, "");
+ if (1 != sscanf(watch+len, "/%u", &dev))
+ dev = -1;
+ }
Overly defensive ifs. You also have open coded calls to fprintf(stderr)
whereas you've introduced a higher level function.
Regards,
Anthony Liguori
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