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: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKeir Fraser <keir.fraser@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In unmask_evtchn(), when the mask bit is cleared after testing for
pending and the event becomes pending between the test and clear, then
the upcall will not become pending and the event may be lost or
delayed.

Avoid this by always clearing the mask bit before checking for
pending.  If a hypercall is needed, remask the event as
EVTCHNOP_unmask will only retrigger pending events if they were
masked.

This fixes a regression introduced in 3.7 by
b5e57923 (xen/events: fix
unmask_evtchn for PV on HVM guests) which reordered the clear mask and
check pending operations.

Changes in v2:
- set mask before hypercall.

Cc: stable@vger.kernel.org
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

On ARM we want these to be the same size on 32- and 64-bit.

This is an ABI change on ARM. X86 does not change.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Keir (Xen.org) <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: xen-devel@lists.xen.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Starting with win8, vmbus interrupts can be delivered on any VCPU in the guest
and furthermore can be concurrently active on multiple VCPUs. Support this
interrupt delivery model by setting up a separate IDT entry for Hyper-V vmbus.
interrupts. I would like to thank Jan Beulich <JBeulich@suse.com> and
Thomas Gleixner <tglx@linutronix.de>, for their help.

In this version of the patch, based on the feedback, I have merged the IDT
vector for Xen and Hyper-V and made the necessary adjustments. Furhermore,
based on Jan's feedback I have added the necessary compilation switches.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1359940959-32168-3-git-send-email-kys@microsoft.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

It is possible that the call to xen_allocate_irq_dynamic() returns negative
number other than -1.
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NWei Liu <wei.liu2@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

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: [<ffffffff810e9fe0>] __atomic_notifier_call_chain+0x0/0x140

stack backtrace:
Pid: 0, comm: swapper/0 Not tainted 3.6.5 #1
Call Trace:
 <IRQ>  [<ffffffff811259a2>] lockdep_rcu_suspicious+0xe2/0x130
 [<ffffffff810ea10c>] __atomic_notifier_call_chain+0x12c/0x140
 [<ffffffff810e9fe0>] ? atomic_notifier_chain_unregister+0x90/0x90
 [<ffffffff811216cd>] ? trace_hardirqs_off+0xd/0x10
 [<ffffffff810ea136>] atomic_notifier_call_chain+0x16/0x20
 [<ffffffff810777c3>] exit_idle+0x43/0x50
 [<ffffffff81568865>] xen_evtchn_do_upcall+0x25/0x50
 [<ffffffff81aa690e>] xen_do_hypervisor_callback+0x1e/0x30
 <EOI>  [<ffffffff810013aa>] ? hypercall_page+0x3aa/0x1000
 [<ffffffff810013aa>] ? hypercall_page+0x3aa/0x1000
 [<ffffffff81061540>] ? xen_safe_halt+0x10/0x20
 [<ffffffff81075cfa>] ? default_idle+0xba/0x570
 [<ffffffff810778af>] ? cpu_idle+0xdf/0x140
 [<ffffffff81a4d881>] ? rest_init+0x135/0x144
 [<ffffffff81a4d74c>] ? csum_partial_copy_generic+0x16c/0x16c
 [<ffffffff82520c45>] ? start_kernel+0x3db/0x3e8
 [<ffffffff8252066a>] ? repair_env_string+0x5a/0x5a
 [<ffffffff82520356>] ? x86_64_start_reservations+0x131/0x135
 [<ffffffff82524aca>] ? xen_start_kernel+0x465/0x46

Git commit 98ad1cc1
Author: Frederic Weisbecker <fweisbec@gmail.com>
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: NMojiong Qiu <mjqiu@tencent.com>
Cc: stable@vger.kernel.org # from 3.3 and newer.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

On ARM I see:
drivers/xen/events.c:280:13: warning: 'pirq_check_eoi_map' defined but not used
[-Wunused-function]
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen_init_IRQ should be marked __init because it calls other functions
marked __init and is always called by functions marked __init (on both
x86 and arm).

Also remove the unused EXPORT_SYMBOL_GPL(xen_init_IRQ).

Both changes were introduced by "xen/arm: receive Xen events on ARM".
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Reset the IRQ_NOAUTOEN and IRQ_NOREQUEST flags that are enabled by
default on ARM. If IRQ_NOAUTOEN is set, __setup_irq doesn't call
irq_startup, that is responsible for calling irq_unmask at startup time.
As a result event channels remain masked.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

When unmask_evtchn is called, if we already have an event pending, we
just set evtchn_pending_sel waiting for local_irq_enable to be called.
That is because PV guests set the irq_enable pvops to
xen_irq_enable_direct in xen_setup_vcpu_info_placement:
xen_irq_enable_direct is implemented in assembly in
arch/x86/xen/xen-asm.S and call xen_force_evtchn_callback if
XEN_vcpu_info_pending is set.

However HVM guests (and ARM guests) do not change or do not have the
irq_enable pvop, so evtchn_unmask cannot work properly for them.

Considering that having the pending_irq bit set when unmask_evtchn is
called is not very common, and it is simpler to keep the
native_irq_enable implementation for HVM guests (and ARM guests), the
best thing to do is just use the EVTCHNOP_unmask hypercall (Xen
re-injects pending events in response).
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Compile events.c on ARM.
Parse, map and enable the IRQ to get event notifications from the device
tree (node "/xen").
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

All of the bind_XYZ_to_irq do a quick lookup to see if the
event exists. And if it does, then the initialized IRQ number
is returned instead of initializing a new IRQ number.

This patch adds an extra logic to check that the type returned
is proper one and that there is an IRQ handler setup for it.

This patch has the benefit of being able to find drivers that
are doing something naught.

[v1: Enhanced based on Stefano's review]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

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.

CC: stable@kernel.org
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

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: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Tested-by: NTobias Geiger <tobias.geiger@vido.info>
[v1: Added some extra wording to git commit]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

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: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

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: NDaniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

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: NDaniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

There are three different modes: PV, HVM, and initial domain 0. In all
the cases we would return -1 for failure instead of a proper error code.
Fix this by propagating the error code from the generic IRQ code.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The list operation checks whether the 'info' structure that is
retrieved from the list is NULL (otherwise it would not been able
to retrieve it). This check is not neccessary.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In case we can't allocate we are doomed. We should BUG_ON
instead of trying to dereference it later on.
Acked-by: NIan Campbell <ian.campbell@citrix.com>
[v1: Use BUG_ON instead of BUG]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This adds a mechanism to resume selected IRQs during syscore_resume
instead of dpm_resume_noirq.

Under Xen we need to resume IRQs associated with IPIs early enough
that the resched IPI is unmasked and we can therefore schedule
ourselves out of the stop_machine where the suspend/resume takes
place.

This issue was introduced by 676dc3cf "xen: Use IRQF_FORCE_RESUME".
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Jeremy Fitzhardinge <Jeremy.Fitzhardinge@citrix.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Link: http://lkml.kernel.org/r/1318713254.11016.52.camel@dagon.hellion.org.uk
Cc: stable@kernel.org (at least to 2.6.32.y)
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

When we allocate/change the IRQ informations, we do not
need to use spinlocks. We can use a mutex (which is
what the generic IRQ code does for allocations/changes).
Fixes a slew of:

BUG: sleeping function called from invalid context at /linux/kernel/mutex.c:271
in_atomic(): 1, irqs_disabled(): 0, pid: 3216, name: xenstored
2 locks held by xenstored/3216:
 #0:  (&u->bind_mutex){......}, at: [<ffffffffa02e0920>] evtchn_ioctl+0x30/0x3a0 [xen_evtchn]
 #1:  (irq_mapping_update_lock){......}, at: [<ffffffff8138b274>] bind_evtchn_to_irq+0x24/0x90
Pid: 3216, comm: xenstored Not tainted 3.1.0-rc6-00021-g437a3d1 #2
Call Trace:
 [<ffffffff81088d10>] __might_sleep+0x100/0x130
 [<ffffffff81645c2f>] mutex_lock_nested+0x2f/0x50
 [<ffffffff81627529>] __irq_alloc_descs+0x49/0x200
 [<ffffffffa02e0920>] ? evtchn_ioctl+0x30/0x3a0 [xen_evtchn]
 [<ffffffff8138b214>] xen_allocate_irq_dynamic+0x34/0x70
 [<ffffffff8138b2ad>] bind_evtchn_to_irq+0x5d/0x90
 [<ffffffffa02e03c0>] ? evtchn_bind_to_user+0x60/0x60 [xen_evtchn]
 [<ffffffff8138c282>] bind_evtchn_to_irqhandler+0x32/0x80
 [<ffffffffa02e03a9>] evtchn_bind_to_user+0x49/0x60 [xen_evtchn]
 [<ffffffffa02e0a34>] evtchn_ioctl+0x144/0x3a0 [xen_evtchn]
 [<ffffffff811b4070>] ? vfsmount_lock_local_unlock+0x50/0x80
 [<ffffffff811a6a1a>] do_vfs_ioctl+0x9a/0x5e0
 [<ffffffff811b476f>] ? mntput+0x1f/0x30
 [<ffffffff81196259>] ? fput+0x199/0x240
 [<ffffffff811a7001>] sys_ioctl+0xa1/0xb0
 [<ffffffff8164ea82>] system_call_fastpath+0x16/0x1b
Reported-by: NJim Burns <jim_burn@bellsouth.net>
Acked-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

During a kexec boot some virqs such as timer and debugirq were already
registered by the old kernel.  The hypervisor will return -EEXISTS from
the new EVTCHNOP_bind_virq request and the BUG in bind_virq_to_irq()
triggers.  Catch the -EEXISTS error and loop through all possible ports to find
what port belongs to the virq/cpu combo.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
[v2:
  - use NR_EVENT_CHANNELS instead of private MAX_EVTCHNS]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This is a patch to the events.c file that fixed up
whitespaces, tabs and braces errors found by the
checkpatch.pl tools.
Signed-off-by: NRuslan Pisarev <ruslan@rpisarev.org.ua>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In the past (2.6.38) the 'xen_allocate_pirq_gsi' would allocate
an entry in a Linux IRQ -> {XEN_IRQ, type, event, ..} array. All
of that has been removed in 2.6.39 and the Xen IRQ subsystem uses
an linked list that is populated when the call to
'xen_allocate_irq_gsi' (universally done from any of the xen_bind_*
calls) is done. The 'xen_allocate_pirq_gsi' is a NOP and there is
no need for it anymore so lets remove it.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Since they are only called once and the rest of the pci_xen_*
functions follow the same pattern of setup.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

.. which is quite benign.

drivers/xen/events.c:398: warning: unused variable ‘desc’
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Do not use pirq_needs_eoi to decide which irq handler to use because Xen
always returns true if the guest does not support pirq_eoi_map.
Use the trigger information we already have from MP-tables and ACPI.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reported-by: NThomas Goetz <tom.goetz@virtualcomputer.com>
Tested-by: NThomas Goetz <tom.goetz@virtualcomputer.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Change the irq handler of evtchns and pirqs that don't need EOI (pirqs
that correspond to physical edge interrupts) to handle_edge_irq.

Use handle_fasteoi_irq for pirqs that need eoi (they generally
correspond to level triggered irqs), no risk in loosing interrupts
because we have to EOI the irq anyway.

This change has the following benefits:

- it uses the very same handlers that Linux would use on native for the
same irqs (handle_edge_irq for edge irqs and msis, and
handle_fasteoi_irq for everything else);

- it uses these handlers in the same way native code would use them: it
let Linux mask\unmask and ack the irq when Linux want to mask\unmask
and ack the irq;

- it fixes a problem occurring when a driver calls disable_irq() in its
handler: the old code was unconditionally unmasking the evtchn even if
the irq is disabled when irq_eoi was called.

See Documentation/DocBook/genericirq.tmpl for more informations.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
[v1: Fixed space/tab issues]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

And if the other domain forgot to clean up its PIRQs we don't need
to fail the operation. Just take a note of it and continue on.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

We need this to find the real Xen PIRQ value for a device
that requests an MSI or MSI-X. In the past we used
'xen_gsi_from_irq' since that function would return
an Xen PIRQ or GSI depending on the provided IRQ. Now that
we have seperated that we need to use the correct
function.

[v2: Deal with rebase on stable/irq.cleanup]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

We do this via the PHYSDEVOP_irq_status_query support hypervisor call.
We will get a positive value if another domain has binded its
PIRQ to the specified GSI (IRQ line).

[v2: Deal with v2.6.37-rc1 rebase fallout]
[v3: Deal with stable/irq.cleanup fallout]
[v4: xen_ignore_irq->xen_test_irq_shared]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

We check if there is a domain owner for the PCI device. In case of failure
(meaning no domain has registered for this device) we make DOMID_SELF the owner.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[v2: deal with rebasing on v2.6.37-1]
[v3: deal with rebasing on stable/irq.cleanup]
[v4: deal with rebasing on stable/irq.ween_of_nr_irqs]
[v5: deal with rebasing on v2.6.39-rc3]
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: NXiantao Zhang <xiantao.zhang@intel.com>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

Checking 'irq < 0' doesn't work when 'irq' is unsigned.

The assigned bind_evtchn_to_irq() and bind_virq_to_irq()
return int, so using int appears appropriate.
Signed-off-by: NNicolas Kaiser <nikai@nikai.net>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

These functions take irq_data as an argument and avoid a redundant
lookup in the sparse irq case.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Converted with coccinelle.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

These functions take irq_data as an argument and avoid a redundant
lookup in the sparse irq case.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Converted with coccinelle.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

drivers/xen/events.c:396: error: 'struct irq_data' has no member named 'affinity'
Reported-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>