5.10-stable patches

added patches:
	xen-fix-xenstore-initialisation-for-xs_local.patch

diff --git a/queue-5.10/series b/queue-5.10/series
index afdc21069f362b4a31db2df78bad534d0f09b6da..a3351b16cbbfe5ef792a685d9d6ccc6e01017976 100644 (file)
--- a/queue-5.10/series
+++ b/queue-5.10/series
@@ -45,3 +45,4 @@ kvm-nvmx-sync-unsync-d-vmcs02-state-to-vmcs12-on-migration.patch
 kvm-x86-get-smi-pending-status-correctly.patch
 kvm-forbid-the-use-of-tagged-userspace-addresses-for-memslots.patch
 io_uring-fix-wqe-lock-completion_lock-deadlock.patch
+xen-fix-xenstore-initialisation-for-xs_local.patch

diff --git a/queue-5.10/xen-fix-xenstore-initialisation-for-xs_local.patch b/queue-5.10/xen-fix-xenstore-initialisation-for-xs_local.patch
new file mode 100644 (file)
index 0000000..32f654e
--- /dev/null
+++ b/queue-5.10/xen-fix-xenstore-initialisation-for-xs_local.patch
@@ -0,0 +1,92 @@
+From 5f46400f7a6a4fad635d5a79e2aa5a04a30ffea1 Mon Sep 17 00:00:00 2001
+From: David Woodhouse <dwmw@amazon.co.uk>
+Date: Tue, 26 Jan 2021 17:01:49 +0000
+Subject: xen: Fix XenStore initialisation for XS_LOCAL
+
+From: David Woodhouse <dwmw@amazon.co.uk>
+
+commit 5f46400f7a6a4fad635d5a79e2aa5a04a30ffea1 upstream.
+
+In commit 3499ba8198ca ("xen: Fix event channel callback via INTX/GSI")
+I reworked the triggering of xenbus_probe().
+
+I tried to simplify things by taking out the workqueue based startup
+triggered from wake_waiting(); the somewhat poorly named xenbus IRQ
+handler.
+
+I missed the fact that in the XS_LOCAL case (Dom0 starting its own
+xenstored or xenstore-stubdom, which happens after the kernel is booted
+completely), that IRQ-based trigger is still actually needed.
+
+So... put it back, except more cleanly. By just spawning a xenbus_probe
+thread which waits on xb_waitq and runs the probe the first time it
+gets woken, just as the workqueue-based hack did.
+
+This is actually a nicer approach for *all* the back ends with different
+interrupt methods, and we can switch them all over to that without the
+complex conditions for when to trigger it. But not in -rc6. This is
+the minimal fix for the regression, although it's a step in the right
+direction instead of doing a partial revert and actually putting the
+workqueue back. It's also simpler than the workqueue.
+
+Fixes: 3499ba8198ca ("xen: Fix event channel callback via INTX/GSI")
+Reported-by: Juergen Gross <jgross@suse.com>
+Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
+Reviewed-by: Juergen Gross <jgross@suse.com>
+Link: https://lore.kernel.org/r/4c9af052a6e0f6485d1de43f2c38b1461996db99.camel@infradead.org
+Signed-off-by: Juergen Gross <jgross@suse.com>
+Cc: Salvatore Bonaccorso <carnil@debian.org>
+Cc: Jason Andryuk <jandryuk@gmail.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/xen/xenbus/xenbus_probe.c |   31 +++++++++++++++++++++++++++++++
+ 1 file changed, 31 insertions(+)
+
+--- a/drivers/xen/xenbus/xenbus_probe.c
++++ b/drivers/xen/xenbus/xenbus_probe.c
+@@ -714,6 +714,23 @@ static bool xs_hvm_defer_init_for_callba
+ #endif
+ }
+ 
++static int xenbus_probe_thread(void *unused)
++{
++      DEFINE_WAIT(w);
++
++      /*
++       * 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)
+ {
+       /*
+@@ -725,6 +742,20 @@ static int __init xenbus_probe_initcall(
+            !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);