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path: root/drivers/xen/xenbus/xenbus_probe.c
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Diffstat (limited to 'drivers/xen/xenbus/xenbus_probe.c')
-rw-r--r--drivers/xen/xenbus/xenbus_probe.c130
1 files changed, 101 insertions, 29 deletions
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index fe360c33ce71..86fe6e779056 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -65,12 +65,17 @@
#include "xenbus.h"
+static int xs_init_irq = -1;
int xen_store_evtchn;
EXPORT_SYMBOL_GPL(xen_store_evtchn);
struct xenstore_domain_interface *xen_store_interface;
EXPORT_SYMBOL_GPL(xen_store_interface);
+#define XS_INTERFACE_READY \
+ ((xen_store_interface != NULL) && \
+ (xen_store_interface->connection == XENSTORE_CONNECTED))
+
enum xenstore_init xen_store_domain_type;
EXPORT_SYMBOL_GPL(xen_store_domain_type);
@@ -89,9 +94,9 @@ match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
return NULL;
}
-int xenbus_match(struct device *_dev, struct device_driver *_drv)
+int xenbus_match(struct device *_dev, const struct device_driver *_drv)
{
- struct xenbus_driver *drv = to_xenbus_driver(_drv);
+ const struct xenbus_driver *drv = to_xenbus_driver(_drv);
if (!drv->ids)
return 0;
@@ -308,7 +313,7 @@ int xenbus_dev_probe(struct device *_dev)
if (err) {
dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
dev->nodename);
- return err;
+ goto fail_remove;
}
dev->spurious_threshold = 1;
@@ -317,6 +322,12 @@ int xenbus_dev_probe(struct device *_dev)
dev->nodename);
return 0;
+fail_remove:
+ if (drv->remove) {
+ down(&dev->reclaim_sem);
+ drv->remove(dev);
+ up(&dev->reclaim_sem);
+ }
fail_put:
module_put(drv->driver.owner);
fail:
@@ -750,6 +761,20 @@ static void xenbus_probe(void)
{
xenstored_ready = 1;
+ if (!xen_store_interface)
+ xen_store_interface = memremap(xen_store_gfn << XEN_PAGE_SHIFT,
+ XEN_PAGE_SIZE, MEMREMAP_WB);
+ /*
+ * Now it is safe to free the IRQ used for xenstore late
+ * initialization. No need to unbind: it is about to be
+ * bound again from xb_init_comms. Note that calling
+ * unbind_from_irqhandler now would result in xen_evtchn_close()
+ * being called and the event channel not being enabled again
+ * afterwards, resulting in missed event notifications.
+ */
+ if (xs_init_irq >= 0)
+ free_irq(xs_init_irq, &xb_waitq);
+
/*
* In the HVM case, xenbus_init() deferred its call to
* xs_init() in case callbacks were not operational yet.
@@ -796,22 +821,27 @@ static int xenbus_probe_thread(void *unused)
static int __init xenbus_probe_initcall(void)
{
+ if (!xen_domain())
+ return -ENODEV;
+
/*
* Probe XenBus here in the XS_PV case, and also XS_HVM unless we
- * need to wait for the platform PCI device to come up.
+ * need to wait for the platform PCI device to come up or
+ * xen_store_interface is not ready.
*/
if (xen_store_domain_type == XS_PV ||
(xen_store_domain_type == XS_HVM &&
- !xs_hvm_defer_init_for_callback()))
+ !xs_hvm_defer_init_for_callback() &&
+ XS_INTERFACE_READY))
xenbus_probe();
/*
- * For XS_LOCAL, spawn a thread which will wait for xenstored
- * or a xenstore-stubdom to be started, then probe. It will be
- * triggered when communication starts happening, by waiting
- * on xb_waitq.
+ * For XS_LOCAL or when xen_store_interface is not ready, spawn a
+ * thread which will wait for xenstored or a xenstore-stubdom to be
+ * started, then probe. It will be triggered when communication
+ * starts happening, by waiting on xb_waitq.
*/
- if (xen_store_domain_type == XS_LOCAL) {
+ if (xen_store_domain_type == XS_LOCAL || !XS_INTERFACE_READY) {
struct task_struct *probe_task;
probe_task = kthread_run(xenbus_probe_thread, NULL,
@@ -907,10 +937,25 @@ static struct notifier_block xenbus_resume_nb = {
.notifier_call = xenbus_resume_cb,
};
+static irqreturn_t xenbus_late_init(int irq, void *unused)
+{
+ int err;
+ uint64_t v = 0;
+
+ err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
+ if (err || !v || !~v)
+ return IRQ_HANDLED;
+ xen_store_gfn = (unsigned long)v;
+
+ wake_up(&xb_waitq);
+ return IRQ_HANDLED;
+}
+
static int __init xenbus_init(void)
{
int err;
uint64_t v = 0;
+ bool wait = false;
xen_store_domain_type = XS_UNKNOWN;
if (!xen_domain())
@@ -921,9 +966,15 @@ static int __init xenbus_init(void)
if (xen_pv_domain())
xen_store_domain_type = XS_PV;
if (xen_hvm_domain())
+ {
xen_store_domain_type = XS_HVM;
- if (xen_hvm_domain() && xen_initial_domain())
- xen_store_domain_type = XS_LOCAL;
+ err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
+ if (err)
+ goto out_error;
+ xen_store_evtchn = (int)v;
+ if (!v && xen_initial_domain())
+ xen_store_domain_type = XS_LOCAL;
+ }
if (xen_pv_domain() && !xen_start_info->store_evtchn)
xen_store_domain_type = XS_LOCAL;
if (xen_pv_domain() && xen_start_info->store_evtchn)
@@ -942,10 +993,6 @@ static int __init xenbus_init(void)
xen_store_interface = gfn_to_virt(xen_store_gfn);
break;
case XS_HVM:
- err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
- if (err)
- goto out_error;
- xen_store_evtchn = (int)v;
err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
if (err)
goto out_error;
@@ -957,25 +1004,50 @@ static int __init xenbus_init(void)
* been properly initialized. Instead of attempting to map a
* wrong guest physical address return error.
*
- * Also recognize all bits set as an invalid value.
+ * Also recognize all bits set as an invalid/uninitialized value.
*/
- if (!v || !~v) {
+ if (!v) {
err = -ENOENT;
goto out_error;
}
- /* Avoid truncation on 32-bit. */
+ if (v == ~0ULL) {
+ wait = true;
+ } else {
+ /* Avoid truncation on 32-bit. */
#if BITS_PER_LONG == 32
- if (v > ULONG_MAX) {
- pr_err("%s: cannot handle HVM_PARAM_STORE_PFN=%llx > ULONG_MAX\n",
- __func__, v);
- err = -EINVAL;
- goto out_error;
- }
+ if (v > ULONG_MAX) {
+ pr_err("%s: cannot handle HVM_PARAM_STORE_PFN=%llx > ULONG_MAX\n",
+ __func__, v);
+ err = -EINVAL;
+ goto out_error;
+ }
#endif
- xen_store_gfn = (unsigned long)v;
- xen_store_interface =
- xen_remap(xen_store_gfn << XEN_PAGE_SHIFT,
- XEN_PAGE_SIZE);
+ xen_store_gfn = (unsigned long)v;
+ xen_store_interface =
+ memremap(xen_store_gfn << XEN_PAGE_SHIFT,
+ XEN_PAGE_SIZE, MEMREMAP_WB);
+ if (!xen_store_interface) {
+ pr_err("%s: cannot map HVM_PARAM_STORE_PFN=%llx\n",
+ __func__, v);
+ err = -EINVAL;
+ goto out_error;
+ }
+ if (xen_store_interface->connection != XENSTORE_CONNECTED)
+ wait = true;
+ }
+ if (wait) {
+ err = bind_evtchn_to_irqhandler(xen_store_evtchn,
+ xenbus_late_init,
+ 0, "xenstore_late_init",
+ &xb_waitq);
+ if (err < 0) {
+ pr_err("xenstore_late_init couldn't bind irq err=%d\n",
+ err);
+ goto out_error;
+ }
+
+ xs_init_irq = err;
+ }
break;
default:
pr_warn("Xenstore state unknown\n");
generated by cgit (git 2.34.1) at 2025-12-26 06:05:49 +0000