linux-toradex.git/drivers/xen/events.c, branch v3.4.82

xen/events: initialize local per-cpu mask for all possible events

2013-08-29T16:50:12+00:00

commit 84ca7a8e45dafb49cd5ca90a343ba033e2885c17 upstream.

The sizeof() argument in init_evtchn_cpu_bindings() is incorrect
resulting in only the first 64 (or 32 in 32-bit guests) ports having
their bindings being initialized to VCPU 0.

In most cases this does not cause a problem as request_irq() will set
the irq affinity which will set the correct local per-cpu mask.
However, if the request_irq() is called on a VCPU other than 0, there
is a window between the unmasking of the event and the affinity being
set were an event may be lost because it is not locally unmasked on
any VCPU. If request_irq() is called on VCPU 0 then local irqs are
disabled during the window and the race does not occur.

Fix this by initializing all NR_EVENT_CHANNEL bits in the local
per-cpu masks.

Signed-off-by: David Vrabel 
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Greg Kroah-Hartman

xen/events: Handle VIRQ_TIMER before any other hardirq in event loop.

2013-06-07T19:49:34+00:00

commit bee980d9e9642e96351fa3ca9077b853ecf62f57 upstream.

This avoids any other hardirq handler seeing a very stale jiffies
value immediately after wakeup from a long idle period. The one
observable symptom of this was a USB keyboard, with software keyboard
repeat, which would always repeat a key immediately that it was
pressed. This is due to the key press waking the guest, the key
handler immediately runs, sees an old jiffies value, and then that
jiffies value significantly updated, before the key is unpressed.

Reviewed-by: David Vrabel 
Signed-off-by: Keir Fraser 
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Greg Kroah-Hartman

xen/events: fix RCU warning, or Call idle notifier after irq_enter()

2012-11-26T19:37:47+00:00

commit 772aebcefeff310f80e32b874988af0076cb799d upstream.

exit_idle() should be called after irq_enter(), otherwise it throws:

[ INFO: suspicious RCU usage. ]
3.6.5 #1 Not tainted
-------------------------------
include/linux/rcupdate.h:725 rcu_read_lock() used illegally while idle!

other info that might help us debug this:

RCU used illegally from idle CPU!
rcu_scheduler_active = 1, debug_locks = 1
RCU used illegally from extended quiescent state!
1 lock held by swapper/0/0:
 #0:  (rcu_read_lock){......}, at: [] __atomic_notifier_call_chain+0x0/0x140

stack backtrace:
Pid: 0, comm: swapper/0 Not tainted 3.6.5 #1
Call Trace:
   [] lockdep_rcu_suspicious+0xe2/0x130
 [] __atomic_notifier_call_chain+0x12c/0x140
 [] ? atomic_notifier_chain_unregister+0x90/0x90
 [] ? trace_hardirqs_off+0xd/0x10
 [] atomic_notifier_call_chain+0x16/0x20
 [] exit_idle+0x43/0x50
 [] xen_evtchn_do_upcall+0x25/0x50
 [] xen_do_hypervisor_callback+0x1e/0x30
   [] ? hypercall_page+0x3aa/0x1000
 [] ? hypercall_page+0x3aa/0x1000
 [] ? xen_safe_halt+0x10/0x20
 [] ? default_idle+0xba/0x570
 [] ? cpu_idle+0xdf/0x140
 [] ? rest_init+0x135/0x144
 [] ? csum_partial_copy_generic+0x16c/0x16c
 [] ? start_kernel+0x3db/0x3e8
 [] ? repair_env_string+0x5a/0x5a
 [] ? x86_64_start_reservations+0x131/0x135
 [] ? xen_start_kernel+0x465/0x46

Git commit 98ad1cc14a5c4fd658f9d72c6ba5c86dfd3ce0d5
Author: Frederic Weisbecker 
Date:   Fri Oct 7 18:22:09 2011 +0200

    x86: Call idle notifier after irq_enter()

did this, but it missed the Xen code.

Signed-off-by: Mojiong Qiu 
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Greg Kroah-Hartman

xen: do not map the same GSI twice in PVHVM guests.

2012-06-01T07:18:25+00:00

commit 68c2c39a76b094e9b2773e5846424ea674bf2c46 upstream.

PV on HVM guests map GSIs into event channels. At restore time the
event channels are resumed by restore_pirqs.

Device drivers might try to register the same GSI again through ACPI at
restore time, but the GSI has already been mapped and bound by
restore_pirqs. This patch detects these situations and avoids
 mapping the same GSI multiple times.

Without this patch we get:
(XEN) irq.c:2235: dom4: pirq 23 or emuirq 28 already mapped
and waste a pirq.

Signed-off-by: Stefano Stabellini 
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Greg Kroah-Hartman

xen: use the pirq number to check the pirq_eoi_map

2012-04-26T22:02:02+00:00

In pirq_check_eoi_map use the pirq number rather than the Linux irq
number to check whether an eoi is needed in the pirq_eoi_map.

The reason is that the irq number is not always identical to the
pirq number so if we wrongly use the irq number to check the
pirq_eoi_map we are going to check for the wrong pirq to EOI.

As a consequence some interrupts might not be EOI'ed by the
guest correctly.

Signed-off-by: Stefano Stabellini 
Tested-by: Tobias Geiger 
[v1: Added some extra wording to git commit]
Signed-off-by: Konrad Rzeszutek Wilk

xen: support pirq_eoi_map

2012-03-20T19:34:07+00:00

The pirq_eoi_map is a bitmap offered by Xen to check which pirqs need to
be EOI'd without having to issue an hypercall every time.
We use PHYSDEVOP_pirq_eoi_gmfn_v2 to map the bitmap, then if we
succeed we use pirq_eoi_map to check whether pirqs need eoi.

Changes in v3:

- explicitly use PHYSDEVOP_pirq_eoi_gmfn_v2 rather than
PHYSDEVOP_pirq_eoi_gmfn;

- introduce pirq_check_eoi_map, a function to check if a pirq needs an
eoi using the map;

-rename pirq_needs_eoi into pirq_needs_eoi_flag;

- introduce a function pointer called pirq_needs_eoi that is going to be
set to the right implementation depending on the availability of
PHYSDEVOP_pirq_eoi_gmfn_v2.

Signed-off-by: Stefano Stabellini 
Signed-off-by: Konrad Rzeszutek Wilk

xen/events: prevent calling evtchn_get on invalid channels

2011-12-16T16:25:54+00:00

The event channel number provided to evtchn_get can be provided by
userspace, so needs to be checked against the maximum number of event
channels prior to using it to index into evtchn_to_irq.

Signed-off-by: Daniel De Graaf 
Signed-off-by: Konrad Rzeszutek Wilk

xen/event: Add reference counting to event channels

2011-11-21T22:14:48+00:00

Event channels exposed to userspace by the evtchn module may be used by
other modules in an asynchronous manner, which requires that reference
counting be used to prevent the event channel from being closed before
the signals are delivered.

The reference count on new event channels defaults to -1 which indicates
the event channel is not referenced outside the kernel; evtchn_get fails
if called on such an event channel. The event channels made visible to
userspace by evtchn have a normal reference count.

Signed-off-by: Daniel De Graaf 
Signed-off-by: Konrad Rzeszutek Wilk

Merge branch 'stable/cleanups-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

2011-11-07T04:13:34+00:00

* 'stable/cleanups-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: use static initializers in xen-balloon.c
  Xen: fix braces and tabs coding style issue in xenbus_probe.c
  Xen: fix braces coding style issue in xenbus_probe.h
  Xen: fix whitespaces,tabs coding style issue in drivers/xen/pci.c
  Xen: fix braces coding style issue in gntdev.c and grant-table.c
  Xen: fix whitespaces,tabs coding style issue in drivers/xen/events.c
  Xen: fix whitespaces,tabs coding style issue in drivers/xen/balloon.c

Fix up trivial whitespace-conflicts in
 drivers/xen/{balloon.c,pci.c,xenbus/xenbus_probe.c}

Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2011-10-26T14:44:09+00:00

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Add IRQF_RESUME_EARLY and resume such IRQs earlier
  genirq: Fix fatfinered fixup really
  genirq: percpu: allow interrupt type to be set at enable time
  genirq: Add support for per-cpu dev_id interrupts
  genirq: Add IRQCHIP_SKIP_SET_WAKE flag