This patch adds infrastructure for xen front 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 XenStore,
setting up XenStore watches, callbacks on device discovery and state
changes, and handle event channel between the virtual machines.
Call xen_fe_register() function to register XenDevOps, and make sure,
XenDevOps's flags is DEVOPS_FLAG_FE, which is flag bit to point out
the XenDevOps is Xen frontend.
Signed-off-by: Quan Xu <quan...@intel.com>
Signed-off-by: Emil Condrea <emilcond...@gmail.com>
---
Changes in v9:
* xenstore_dev should not be global, it will not work correctly with
multiple xen frontends living in qemu
* reuse some common functions:
- xen_fe_printf -> xen_pv_printf
- xen_fe_evtchn_event -> xen_pv_evtchn_event
* use libxenevtchn stable API instead of xc_* calls:
- xc_evtchn_fd -> xenevtchn_fd
- xc_evtchn_close -> xenevtchn_close
- xc_evtchn_bind_unbound_port -> xenevtchn_bind_unbound_port
---
hw/xen/xen_frontend.c | 308 ++++++++++++++++++++++++++++++++++++++++++
hw/xen/xen_pvdev.c | 15 ++
include/hw/xen/xen_frontend.h | 6 +
include/hw/xen/xen_pvdev.h | 1 +
4 files changed, 330 insertions(+)
diff --git a/hw/xen/xen_frontend.c b/hw/xen/xen_frontend.c
index 6b92cf1..7b305ce 100644
--- a/hw/xen/xen_frontend.c
+++ b/hw/xen/xen_frontend.c
@@ -3,6 +3,10 @@
*
* (c) 2008 Gerd Hoffmann <kra...@redhat.com>
*
+ * Copyright (c) 2015 Intel Corporation
+ * Authors:
+ * Quan Xu <quan...@intel.com>
+ *
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
@@ -23,6 +27,8 @@
#include "hw/xen/xen_frontend.h"
#include "hw/xen/xen_backend.h"
+static int debug = 0;
+
char *xenstore_read_fe_str(struct XenDevice *xendev, const char *node)
{
return xenstore_read_str(xendev->fe, node);
@@ -86,3 +92,305 @@ void xenstore_update_fe(char *watch, struct XenDevice
*xendev)
xen_fe_frontend_changed(xendev, node);
xen_be_check_state(xendev);
}
+
+struct XenDevice *xen_fe_get_xendev(const char *type, int dom, int dev,
+ char *backend, struct XenDevOps *ops)
+{
+ struct XenDevice *xendev;
+
+ xendev = xen_pv_find_xendev(type, dom, dev);
+ if (xendev) {
+ return xendev;
+ }
+
+ /* init new xendev */
+ xendev = g_malloc0(ops->size);
+ xendev->type = type;
+ xendev->dom = dom;
+ xendev->dev = dev;
+ xendev->ops = ops;
+
+ /*return if the ops->flags is not DEVOPS_FLAG_FE*/
+ if (!(ops->flags & DEVOPS_FLAG_FE)) {
+ return NULL;
+ }
+
+ snprintf(xendev->be, sizeof(xendev->be), "%s", backend);
+ snprintf(xendev->name, sizeof(xendev->name), "%s-%d",
+ xendev->type, xendev->dev);
+
+ xendev->debug = debug;
+ xendev->local_port = -1;
+
+ xendev->evtchndev = xenevtchn_open(NULL, 0);
+ if (xendev->evtchndev == NULL) {
+ xen_pv_printf(NULL, 0, "can't open evtchn device\n");
+ g_free(xendev);
+ return NULL;
+ }
+ fcntl(xenevtchn_fd(xendev->evtchndev), F_SETFD, FD_CLOEXEC);
+
+ if (ops->flags & DEVOPS_FLAG_NEED_GNTDEV) {
+ xendev->gnttabdev = xengnttab_open(NULL, 0);
+ if (xendev->gnttabdev == NULL) {
+ xen_pv_printf(NULL, 0, "can't open gnttab device\n");
+ xenevtchn_close(xendev->evtchndev);
+ g_free(xendev);
+ return NULL;
+ }
+ } else {
+ xendev->gnttabdev = NULL;
+ }
+
+ xen_pv_insert_xendev(xendev);
+
+ if (xendev->ops->alloc) {
+ xendev->ops->alloc(xendev);
+ }
+
+ return xendev;
+}
+
+int xen_fe_alloc_unbound(struct XenDevice *xendev, int dom, int remote_dom){
+ xendev->local_port = xenevtchn_bind_unbound_port(xendev->evtchndev,
+ remote_dom);
+ if (xendev->local_port == -1) {
+ xen_pv_printf(xendev, 0, "xenevtchn_bind_unbound_port failed\n");
+ return -1;
+ }
+ xen_pv_printf(xendev, 2, "bind evtchn port %d\n", xendev->local_port);
+ qemu_set_fd_handler(xenevtchn_fd(xendev->evtchndev),
+ xen_pv_evtchn_event, NULL, xendev);
+ return 0;
+}
+
+/*
+ * Make sure, initialize the 'xendev->fe' in xendev->ops->init() or
+ * xendev->ops->initialize()
+ */
+int xenbus_switch_state(struct XenDevice *xendev, enum xenbus_state xbus)
+{
+ xs_transaction_t xbt = XBT_NULL;
+
+ if (xendev->fe_state == xbus) {
+ return 0;
+ }
+
+ xendev->fe_state = xbus;
+ if (xendev->fe == NULL) {
+ xen_pv_printf(NULL, 0, "xendev->fe is NULL\n");
+ return -1;
+ }
+
+retry_transaction:
+ xbt = xs_transaction_start(xenstore);
+ if (xbt == XBT_NULL) {
+ goto abort_transaction;
+ }
+
+ if (xenstore_write_int(xendev->fe, "state", xbus)) {
+ goto abort_transaction;
+ }
+
+ if (!xs_transaction_end(xenstore, xbt, 0)) {
+ if (errno == EAGAIN) {
+ goto retry_transaction;
+ }
+ }
+
+ return 0;
+
+abort_transaction:
+ xs_transaction_end(xenstore, xbt, 1);
+ return -1;
+}
+
+/*
+ * Simplify QEMU side, a thread is running in Xen backend, which will
+ * connect frontend when the frontend is initialised. Call these initialised
+ * functions.
+ */
+static int xen_fe_try_init(void *opaque)
+{
+ struct XenDevOps *ops = opaque;
+ int rc = -1;
+
+ if (ops->init) {
+ rc = ops->init(NULL);
+ }
+
+ return rc;
+}
+
+static int xen_fe_try_initialise(struct XenDevice *xendev)
+{
+ int rc = 0, fe_state;
+
+ if (xenstore_read_fe_int(xendev, "state", &fe_state) == -1) {
+ fe_state = XenbusStateUnknown;
+ }
+ xendev->fe_state = fe_state;
+
+ if (xendev->ops->initialise) {
+ rc = xendev->ops->initialise(xendev);
+ }
+ if (rc != 0) {
+ xen_pv_printf(xendev, 0, "initialise() failed\n");
+ return rc;
+ }
+
+ xenbus_switch_state(xendev, XenbusStateInitialised);
+ return 0;
+}
+
+static void xen_fe_try_connected(struct XenDevice *xendev)
+{
+ if (!xendev->ops->connected) {
+ return;
+ }
+
+ if (xendev->fe_state != XenbusStateConnected) {
+ if (xendev->ops->flags & DEVOPS_FLAG_IGNORE_STATE) {
+ xen_pv_printf(xendev, 2, "frontend not ready, ignoring\n");
+ } else {
+ xen_pv_printf(xendev, 2, "frontend not ready (yet)\n");
+ return;
+ }
+ }
+
+ xendev->ops->connected(xendev);
+}
+
+static int xen_fe_check(struct XenDevice *xendev, uint32_t domid,
+ int handle)
+{
+ int rc = 0;
+
+ rc = xen_fe_try_initialise(xendev);
+ if (rc != 0) {
+ xen_pv_printf(xendev, 0, "xendev %s initialise error\n",
+ xendev->name);
+ goto err;
+ }
+ xen_fe_try_connected(xendev);
+
+ return rc;
+
+err:
+ xen_pv_del_xendev(domid, handle);
+ return -1;
+}
+
+static char *xenstore_fe_get_backend(const char *type, int be_domid,
+ uint32_t domid, int *hdl)
+{
+ char *name, *str, *ret = NULL;
+ uint32_t i, cdev;
+ int handle = 0;
+ char path[XEN_BUFSIZE];
+ char **dev = NULL;
+
+ name = xenstore_get_domain_name(domid);
+ snprintf(path, sizeof(path), "frontend/%s/%d", type, be_domid);
+ dev = xs_directory(xenstore, 0, path, &cdev);
+ for (i = 0; i < cdev; i++) {
+ handle = i;
+ snprintf(path, sizeof(path), "frontend/%s/%d/%d",
+ type, be_domid, handle);
+ str = xenstore_read_str(path, "domain");
+ if (!strcmp(name, str)) {
+ break;
+ }
+
+ free(str);
+
+ /* Not the backend domain */
+ if (handle == (cdev - 1)) {
+ goto err;
+ }
+ }
+
+ snprintf(path, sizeof(path), "frontend/%s/%d/%d",
+ type, be_domid, handle);
+ str = xenstore_read_str(path, "backend");
+ if (str != NULL) {
+ ret = g_strdup(str);
+ free(str);
+ }
+
+ *hdl = handle;
+ free(dev);
+
+ return ret;
+err:
+ *hdl = -1;
+ free(dev);
+ return NULL;
+}
+
+static int xenstore_fe_scan(const char *type, uint32_t domid,
+ struct XenDevOps *ops)
+{
+ struct XenDevice *xendev;
+ char path[XEN_BUFSIZE], token[XEN_BUFSIZE];
+ unsigned int cdev, j;
+ char *backend;
+ char **dev = NULL;
+ int rc;
+ int xenstore_dev;
+
+ /* ops .init check, xendev is NOT initialized */
+ rc = xen_fe_try_init(ops);
+ if (rc != 0) {
+ return -1;
+ }
+
+ /* Get /local/domain/0/${type}/{} directory */
+ snprintf(path, sizeof(path), "frontend/%s", type);
+ dev = xs_directory(xenstore, 0, path, &cdev);
+ if (dev == NULL) {
+ return 0;
+ }
+
+ for (j = 0; j < cdev; j++) {
+
+ /* Get backend via domain name */
+ backend = xenstore_fe_get_backend(type, atoi(dev[j]),
+ domid, &xenstore_dev);
+ if (backend == NULL) {
+ continue;
+ }
+
+ xendev = xen_fe_get_xendev(type, domid, xenstore_dev, backend, ops);
+ free(backend);
+ if (xendev == NULL) {
+ xen_pv_printf(xendev, 0, "xendev is NULL.\n");
+ continue;
+ }
+
+ /*
+ * Simplify QEMU side, a thread is running in Xen backend, which will
+ * connect frontend when the frontend is initialised.
+ */
+ if (xen_fe_check(xendev, domid, xenstore_dev) < 0) {
+ xen_pv_printf(xendev, 0, "xendev fe_check error.\n");
+ continue;
+ }
+
+ /* Setup watch */
+ snprintf(token, sizeof(token), "be:%p:%d:%p",
+ type, domid, xendev->ops);
+ if (!xs_watch(xenstore, xendev->be, token)) {
+ xen_pv_printf(xendev, 0, "xs_watch failed.\n");
+ continue;
+ }
+ }
+
+ free(dev);
+ return 0;
+}
+
+int xen_fe_register(const char *type, struct XenDevOps *ops)
+{
+ return xenstore_fe_scan(type, xen_domid, ops);
+}
diff --git a/hw/xen/xen_pvdev.c b/hw/xen/xen_pvdev.c
index 394ddc1..cb51e87 100644
--- a/hw/xen/xen_pvdev.c
+++ b/hw/xen/xen_pvdev.c
@@ -121,6 +121,21 @@ cleanup:
free(vec);
}
+char *xenstore_get_domain_name(uint32_t domid)
+{
+ char *dom_path, *str, *ret = NULL;
+
+ dom_path = xs_get_domain_path(xenstore, domid);
+ str = xenstore_read_str(dom_path, "name");
+ free(dom_path);
+ if (str != NULL) {
+ ret = g_strdup(str);
+ free(str);
+ }
+
+ return ret;
+}
+
const char *xenbus_strstate(enum xenbus_state state)
{
static const char *const name[] = {
diff --git a/include/hw/xen/xen_frontend.h b/include/hw/xen/xen_frontend.h
index 5d03f4e..8fc0422 100644
--- a/include/hw/xen/xen_frontend.h
+++ b/include/hw/xen/xen_frontend.h
@@ -8,6 +8,12 @@ int xenstore_read_fe_int(struct XenDevice *xendev, const char
*node, int *ival);
int xenstore_read_fe_uint64(struct XenDevice *xendev, const char *node,
uint64_t *uval);
void xenstore_update_fe(char *watch, struct XenDevice *xendev);
+struct XenDevice *xen_fe_get_xendev(const char *type, int dom, int dev,
+ char *backend, struct XenDevOps *ops);
void xen_fe_frontend_changed(struct XenDevice *xendev, const char *node);
+int xen_fe_register(const char *type, struct XenDevOps *ops);
+int xen_fe_alloc_unbound(struct XenDevice *xendev, int dom, int remote_dom);
+int xenbus_switch_state(struct XenDevice *xendev, enum xenbus_state xbus);
+
#endif /* QEMU_HW_XEN_FRONTEND_H */
diff --git a/include/hw/xen/xen_pvdev.h b/include/hw/xen/xen_pvdev.h
index c985a9d..11bab56 100644
--- a/include/hw/xen/xen_pvdev.h
+++ b/include/hw/xen/xen_pvdev.h
@@ -65,6 +65,7 @@ char *xenstore_read_str(const char *base, const char *node);
int xenstore_read_int(const char *base, const char *node, int *ival);
int xenstore_read_uint64(const char *base, const char *node, uint64_t *uval);
void xenstore_update(void *unused);
+char *xenstore_get_domain_name(uint32_t domid);
const char *xenbus_strstate(enum xenbus_state state);
--
1.9.1
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