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author | David Woodhouse <dwmw@amazon.co.uk> | |
Wed, 13 Jan 2021 13:26:02 +0000 (13:26 +0000) | ||
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
Wed, 27 Jan 2021 10:47:44 +0000 (11:47 +0100) |
[ Upstream commit 3499ba8198cad47b731792e5e56b9ec2a78a83a2 ]
For a while, event channel notification via the PCI platform device
has been broken, because we attempt to communicate with xenstore before
we even have notifications working, with the xs_reset_watches() call
in xs_init().
We tend to get away with this on Xen versions below 4.0 because we avoid
calling xs_reset_watches() anyway, because xenstore might not cope with
reading a non-existent key. And newer Xen *does* have the vector
callback support, so we rarely fall back to INTX/GSI delivery.
To fix it, clean up a bit of the mess of xs_init() and xenbus_probe()
startup. Call xs_init() directly from xenbus_init() only in the !XS_HVM
case, deferring it to be called from xenbus_probe() in the XS_HVM case
instead.
Then fix up the invocation of xenbus_probe() to happen either from its
device_initcall if the callback is available early enough, or when the
callback is finally set up. This means that the hack of calling
xenbus_probe() from a workqueue after the first interrupt, or directly
from the PCI platform device setup, is no longer needed.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210113132606.422794-2-dwmw2@infradead.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
For a while, event channel notification via the PCI platform device
has been broken, because we attempt to communicate with xenstore before
we even have notifications working, with the xs_reset_watches() call
in xs_init().
We tend to get away with this on Xen versions below 4.0 because we avoid
calling xs_reset_watches() anyway, because xenstore might not cope with
reading a non-existent key. And newer Xen *does* have the vector
callback support, so we rarely fall back to INTX/GSI delivery.
To fix it, clean up a bit of the mess of xs_init() and xenbus_probe()
startup. Call xs_init() directly from xenbus_init() only in the !XS_HVM
case, deferring it to be called from xenbus_probe() in the XS_HVM case
instead.
Then fix up the invocation of xenbus_probe() to happen either from its
device_initcall if the callback is available early enough, or when the
callback is finally set up. This means that the hack of calling
xenbus_probe() from a workqueue after the first interrupt, or directly
from the PCI platform device setup, is no longer needed.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210113132606.422794-2-dwmw2@infradead.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
index dd6804a64f1a041935e80919678be6c8f22594e6..f45bff158fc203c0583a8d32ca74400259c9cccd 100644 (file)
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
}
gnttab_init();
if (!xen_initial_domain())
- xenbus_probe(NULL);
+ xenbus_probe();
/*
* Making sure board specific code will not set up ops for
index 26df84c45db4e651c2cd4f5f9c7c1dfa819c02ae..7b94a6c316643f389a72f0b6fd638b724237e0c6 100644 (file)
.irq_ack = ack_dynirq,
};
-int xen_set_callback_via(uint64_t via)
-{
- struct xen_hvm_param a;
- a.domid = DOMID_SELF;
- a.index = HVM_PARAM_CALLBACK_IRQ;
- a.value = via;
- return HYPERVISOR_hvm_op(HVMOP_set_param, &a);
-}
-EXPORT_SYMBOL_GPL(xen_set_callback_via);
-
#ifdef CONFIG_XEN_PVHVM
/* Vector callbacks are better than PCI interrupts to receive event
* channel notifications because we can receive vector callbacks on any
index 5e30602fdbad8b561c9b5b5456f8efc92ca7718e..c45646450135fbd010ad8bf62e6a0285aee72c86 100644 (file)
ret = gnttab_init();
if (ret)
goto grant_out;
- xenbus_probe(NULL);
return 0;
grant_out:
gnttab_free_auto_xlat_frames();
index 88516a8a9f932e16b3edfa37e76d72a2c0cd9648..a9bb5f91082d39f9037ea8db484d76c3e09b3264 100644 (file)
const char *type,
const char *nodename);
int xenbus_probe_devices(struct xen_bus_type *bus);
+void xenbus_probe(void);
void xenbus_dev_changed(const char *node, struct xen_bus_type *bus);
index eb5151fc8efab02899ce764b99a8d6f2955e9ca7..e5fda0256feb3d476aeee5f2d1e28ac7bd29f226 100644 (file)
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;
}
index e6d0903459e11a58fdff58d12ece2b9169d1b570..14ccf13ab8fa10681d204a1932a9a76ca7447cf8 100644 (file)
}
EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
-void xenbus_probe(struct work_struct *unused)
+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 __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();
- xenbus_probe(NULL);
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)
*/
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/include/xen/xenbus.h b/include/xen/xenbus.h
index eba01ab5a55e039219ddc5d87755f7b3a6c9c71b..fe9a9fa2ebc45cbc3543cff98fc05b3b34199d76 100644 (file)
--- a/include/xen/xenbus.h
+++ b/include/xen/xenbus.h
struct work_struct;
-void xenbus_probe(struct work_struct *);
+void xenbus_probe(void);
#define XENBUS_IS_ERR_READ(str) ({ \
if (!IS_ERR(str) && strlen(str) == 0) { \