Update Linux to v5.4.148
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz
Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/drivers/xen/xenbus/xenbus.h b/drivers/xen/xenbus/xenbus.h
index d75a238..88516a8 100644
--- a/drivers/xen/xenbus/xenbus.h
+++ b/drivers/xen/xenbus/xenbus.h
@@ -44,6 +44,8 @@
int (*get_bus_id)(char bus_id[XEN_BUS_ID_SIZE], const char *nodename);
int (*probe)(struct xen_bus_type *bus, const char *type,
const char *dir);
+ bool (*otherend_will_handle)(struct xenbus_watch *watch,
+ const char *path, const char *token);
void (*otherend_changed)(struct xenbus_watch *watch, const char *path,
const char *token);
struct bus_type bus;
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index e17ca81..81eddb8 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -114,18 +114,22 @@
*/
int xenbus_watch_path(struct xenbus_device *dev, const char *path,
struct xenbus_watch *watch,
+ bool (*will_handle)(struct xenbus_watch *,
+ const char *, const char *),
void (*callback)(struct xenbus_watch *,
const char *, const char *))
{
int err;
watch->node = path;
+ watch->will_handle = will_handle;
watch->callback = callback;
err = register_xenbus_watch(watch);
if (err) {
watch->node = NULL;
+ watch->will_handle = NULL;
watch->callback = NULL;
xenbus_dev_fatal(dev, err, "adding watch on %s", path);
}
@@ -152,6 +156,8 @@
*/
int xenbus_watch_pathfmt(struct xenbus_device *dev,
struct xenbus_watch *watch,
+ bool (*will_handle)(struct xenbus_watch *,
+ const char *, const char *),
void (*callback)(struct xenbus_watch *,
const char *, const char *),
const char *pathfmt, ...)
@@ -168,7 +174,7 @@
xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch");
return -ENOMEM;
}
- err = xenbus_watch_path(dev, path, watch, callback);
+ err = xenbus_watch_path(dev, path, watch, will_handle, callback);
if (err)
kfree(path);
@@ -363,8 +369,14 @@
int i, j;
for (i = 0; i < nr_pages; i++) {
- err = gnttab_grant_foreign_access(dev->otherend_id,
- virt_to_gfn(vaddr), 0);
+ unsigned long gfn;
+
+ if (is_vmalloc_addr(vaddr))
+ gfn = pfn_to_gfn(vmalloc_to_pfn(vaddr));
+ else
+ gfn = virt_to_gfn(vaddr);
+
+ err = gnttab_grant_foreign_access(dev->otherend_id, gfn, 0);
if (err < 0) {
xenbus_dev_fatal(dev, err,
"granting access to ring page");
@@ -448,7 +460,14 @@
int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
unsigned int nr_grefs, void **vaddr)
{
- return ring_ops->map(dev, gnt_refs, nr_grefs, vaddr);
+ int err;
+
+ err = ring_ops->map(dev, gnt_refs, nr_grefs, vaddr);
+ /* Some hypervisors are buggy and can return 1. */
+ if (err > 0)
+ err = GNTST_general_error;
+
+ return err;
}
EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);
diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c
index d239fc3..e5fda02 100644
--- a/drivers/xen/xenbus/xenbus_comms.c
+++ b/drivers/xen/xenbus/xenbus_comms.c
@@ -57,16 +57,8 @@
static int xenbus_irq;
static struct task_struct *xenbus_task;
-static DECLARE_WORK(probe_work, xenbus_probe);
-
-
static irqreturn_t wake_waiting(int irq, void *unused)
{
- if (unlikely(xenstored_ready == 0)) {
- xenstored_ready = 1;
- schedule_work(&probe_work);
- }
-
wake_up(&xb_waitq);
return IRQ_HANDLED;
}
@@ -313,6 +305,8 @@
req->msg.type = state.msg.type;
req->msg.len = state.msg.len;
req->body = state.body;
+ /* write body, then update state */
+ virt_wmb();
req->state = xb_req_state_got_reply;
req->cb(req);
} else
@@ -395,6 +389,8 @@
if (state.req->state == xb_req_state_aborted)
kfree(state.req);
else {
+ /* write err, then update state */
+ virt_wmb();
state.req->state = xb_req_state_got_reply;
wake_up(&state.req->wq);
}
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 5b47188..652894d 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -136,6 +136,7 @@
container_of(dev->dev.bus, struct xen_bus_type, bus);
return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
+ bus->otherend_will_handle,
bus->otherend_changed,
"%s/%s", dev->otherend, "state");
}
@@ -682,29 +683,107 @@
}
EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
-void xenbus_probe(struct work_struct *unused)
+static void xenbus_probe(void)
{
xenstored_ready = 1;
+ /*
+ * In the HVM case, xenbus_init() deferred its call to
+ * xs_init() in case callbacks were not operational yet.
+ * So do it now.
+ */
+ if (xen_store_domain_type == XS_HVM)
+ xs_init();
+
/* Notify others that xenstore is up */
blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
}
-EXPORT_SYMBOL_GPL(xenbus_probe);
-static int __init xenbus_probe_initcall(void)
+/*
+ * Returns true when XenStore init must be deferred in order to
+ * allow the PCI platform device to be initialised, before we
+ * can actually have event channel interrupts working.
+ */
+static bool xs_hvm_defer_init_for_callback(void)
{
- if (!xen_domain())
- return -ENODEV;
+#ifdef CONFIG_XEN_PVHVM
+ return xen_store_domain_type == XS_HVM &&
+ !xen_have_vector_callback;
+#else
+ return false;
+#endif
+}
- if (xen_initial_domain() || xen_hvm_domain())
- return 0;
+static int xenbus_probe_thread(void *unused)
+{
+ DEFINE_WAIT(w);
- xenbus_probe(NULL);
+ /*
+ * We actually just want to wait for *any* trigger of xb_waitq,
+ * and run xenbus_probe() the moment it occurs.
+ */
+ prepare_to_wait(&xb_waitq, &w, TASK_INTERRUPTIBLE);
+ schedule();
+ finish_wait(&xb_waitq, &w);
+
+ DPRINTK("probing");
+ xenbus_probe();
return 0;
}
+static int __init xenbus_probe_initcall(void)
+{
+ /*
+ * 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.
+ */
+ if (xen_store_domain_type == XS_PV ||
+ (xen_store_domain_type == XS_HVM &&
+ !xs_hvm_defer_init_for_callback()))
+ 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.
+ */
+ if (xen_store_domain_type == XS_LOCAL) {
+ struct task_struct *probe_task;
+
+ probe_task = kthread_run(xenbus_probe_thread, NULL,
+ "xenbus_probe");
+ if (IS_ERR(probe_task))
+ return PTR_ERR(probe_task);
+ }
+ return 0;
+}
device_initcall(xenbus_probe_initcall);
+int xen_set_callback_via(uint64_t via)
+{
+ struct xen_hvm_param a;
+ int ret;
+
+ a.domid = DOMID_SELF;
+ a.index = HVM_PARAM_CALLBACK_IRQ;
+ a.value = via;
+
+ ret = HYPERVISOR_hvm_op(HVMOP_set_param, &a);
+ if (ret)
+ return ret;
+
+ /*
+ * If xenbus_probe_initcall() deferred the xenbus_probe()
+ * due to the callback not functioning yet, we can do it now.
+ */
+ if (!xenstored_ready && xs_hvm_defer_init_for_callback())
+ xenbus_probe();
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(xen_set_callback_via);
+
/* Set up event channel for xenstored which is run as a local process
* (this is normally used only in dom0)
*/
@@ -817,11 +896,17 @@
break;
}
- /* Initialize the interface to xenstore. */
- err = xs_init();
- if (err) {
- pr_warn("Error initializing xenstore comms: %i\n", err);
- goto out_error;
+ /*
+ * HVM domains may not have a functional callback yet. In that
+ * case let xs_init() be called from xenbus_probe(), which will
+ * get invoked at an appropriate time.
+ */
+ if (xen_store_domain_type != XS_HVM) {
+ err = xs_init();
+ if (err) {
+ pr_warn("Error initializing xenstore comms: %i\n", err);
+ goto out_error;
+ }
}
if ((xen_store_domain_type != XS_LOCAL) &&
diff --git a/drivers/xen/xenbus/xenbus_probe_backend.c b/drivers/xen/xenbus/xenbus_probe_backend.c
index b0bed4f..4bb6030 100644
--- a/drivers/xen/xenbus/xenbus_probe_backend.c
+++ b/drivers/xen/xenbus/xenbus_probe_backend.c
@@ -180,6 +180,12 @@
return err;
}
+static bool frontend_will_handle(struct xenbus_watch *watch,
+ const char *path, const char *token)
+{
+ return watch->nr_pending == 0;
+}
+
static void frontend_changed(struct xenbus_watch *watch,
const char *path, const char *token)
{
@@ -191,6 +197,7 @@
.levels = 3, /* backend/type/<frontend>/<id> */
.get_bus_id = backend_bus_id,
.probe = xenbus_probe_backend,
+ .otherend_will_handle = frontend_will_handle,
.otherend_changed = frontend_changed,
.bus = {
.name = "xen-backend",
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index ddc18da..12e02eb 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -191,8 +191,11 @@
static bool test_reply(struct xb_req_data *req)
{
- if (req->state == xb_req_state_got_reply || !xenbus_ok())
+ if (req->state == xb_req_state_got_reply || !xenbus_ok()) {
+ /* read req->state before all other fields */
+ virt_rmb();
return true;
+ }
/* Make sure to reread req->state each time. */
barrier();
@@ -202,7 +205,7 @@
static void *read_reply(struct xb_req_data *req)
{
- while (req->state != xb_req_state_got_reply) {
+ do {
wait_event(req->wq, test_reply(req));
if (!xenbus_ok())
@@ -216,7 +219,7 @@
if (req->err)
return ERR_PTR(req->err);
- }
+ } while (req->state != xb_req_state_got_reply);
return req->body;
}
@@ -702,9 +705,13 @@
spin_lock(&watches_lock);
event->handle = find_watch(event->token);
- if (event->handle != NULL) {
+ if (event->handle != NULL &&
+ (!event->handle->will_handle ||
+ event->handle->will_handle(event->handle,
+ event->path, event->token))) {
spin_lock(&watch_events_lock);
list_add_tail(&event->list, &watch_events);
+ event->handle->nr_pending++;
wake_up(&watch_events_waitq);
spin_unlock(&watch_events_lock);
} else
@@ -762,6 +769,8 @@
sprintf(token, "%lX", (long)watch);
+ watch->nr_pending = 0;
+
down_read(&xs_watch_rwsem);
spin_lock(&watches_lock);
@@ -811,11 +820,14 @@
/* Cancel pending watch events. */
spin_lock(&watch_events_lock);
- list_for_each_entry_safe(event, tmp, &watch_events, list) {
- if (event->handle != watch)
- continue;
- list_del(&event->list);
- kfree(event);
+ if (watch->nr_pending) {
+ list_for_each_entry_safe(event, tmp, &watch_events, list) {
+ if (event->handle != watch)
+ continue;
+ list_del(&event->list);
+ kfree(event);
+ }
+ watch->nr_pending = 0;
}
spin_unlock(&watch_events_lock);
@@ -862,7 +874,6 @@
static int xenwatch_thread(void *unused)
{
- struct list_head *ent;
struct xs_watch_event *event;
xenwatch_pid = current->pid;
@@ -877,13 +888,15 @@
mutex_lock(&xenwatch_mutex);
spin_lock(&watch_events_lock);
- ent = watch_events.next;
- if (ent != &watch_events)
- list_del(ent);
+ event = list_first_entry_or_null(&watch_events,
+ struct xs_watch_event, list);
+ if (event) {
+ list_del(&event->list);
+ event->handle->nr_pending--;
+ }
spin_unlock(&watch_events_lock);
- if (ent != &watch_events) {
- event = list_entry(ent, struct xs_watch_event, list);
+ if (event) {
event->handle->callback(event->handle, event->path,
event->token);
kfree(event);