Calling PHYSDEVOP_map_pirq earlier simplifies error handling and
starts to make the tail end of this function look like
xen_bind_pirq_msi_to_irq.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Split the binding aspect of xen_allocate_pirq_msi out into a new
xen_bind_pirq_to_irq function.
In xen_hvm_setup_msi_irq when allocating a pirq write the MSI message
to signal the PIRQ as soon as the pirq is obtained. There is no way to
free the pirq back so if the subsequent binding to an IRQ fails we
want to ensure that we will reuse the PIRQ next time rather than leak
it.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The find_unbound_pirq is called only from xen_allocate_pirq_msi and
only if alloc_pirq is true. The only caller which does this is
xen_hvm_setup_msi_irqs. The use of this function is gated, in
pci_xen_hvm_init, on XENFEAT_hvm_pirqs.
The PHYSDEVOP_get_free_pirq interfaces was added to the hypervisor in
22410:be96f6058c05 while XENFEAT_hvm_pirqs was added a couple of
minutes prior in 22409:6663214f06ac. Therefore we do not need to
concern ourselves with hypervisors which support XENFEAT_hvm_pirqs but
not PHYSDEVOP_get_free_pirq.
This eliminates the fallback path in find_unbound_pirq which walks to
pirq_to_irq array looking for a free pirq. Unlike the
PHYSDEVOP_get_free_pirq interface this fallback only looks up a free
pirq but does not reserve it. Removing this fallback will simplify
locking in the future.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
consistent with other similar functions.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
All callers pass this flag so it is pointless.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: xen-devel@lists.xensource.com
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
We only did this for PV guests that are xen_initial_domain() but
there is not reason not to do this for other cases. The other
case is only exercised when you pass in a PCI device to a PV guest
_and_ the device in question.
Reviewed-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Mark the IRQF_NO_SUSPEND interrupts IRQF_FORCE_RESUME and remove the extra
walk through the interrupt descriptors.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
drivers/xen/events.c: In function 'ack_pirq':
drivers/xen/events.c:568: error: implicit declaration of function 'irq_move_irq'
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Convert Xen to the new irq_chip functions. Brings us closer to enable
CONFIG_GENERIC_HARDIRQS_NO_DEPRECATED
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
irq_chip.end got obsolete with the removal of __do_IRQ()
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
c514d00c8057 "xen: events: add xen_allocate_irq_{dynamic, gsi} and
xen_free_irq" correctly avoids reallocating legacy IRQs (which are
managed by the arch core) but erroneously did not prevent them being
freed.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
There are three cases which we need to care about, PV guest, PV domain
0 and HVM guest.
The PV guest case is simple since it has no access to ACPI or real
APICs and therefore has no GSIs therefore we simply dynamically
allocate all IRQs. The potentially interesting case here is PIRQ type
event channels associated with passed through PCI devices. However
even in this case the guest has no direct interaction with the
physical GSI since that happens in the PCI backend.
The PV domain 0 and HVM guest cases are actually the same. In domain 0
case the kernel sees the host ACPI and GSIs (although it only sees the
APIC indirectly via the hypervisor) and in the HVM guest case it sees
the virtualised ACPI and emulated APICs. In these cases we start
allocating dynamic IRQs at nr_irqs_gsi so that they cannot clash with
any GSI.
Currently xen_allocate_irq_dynamic starts at nr_irqs and works
backwards looking for a free IRQ in order to (try and) avoid clashing
with GSIs used in domain 0 and in HVM guests. This change avoids that
although we retain the behaviour of allowing dynamic IRQs to encroach
on the GSI range if no suitable IRQs are available since a future IRQ
clash is deemed preferable to failure right now.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
This is neater than open-coded calls to irq_alloc_desc_at and
irq_free_desc.
No intended behavioural change.
Note that we previously were not checking the return value of
irq_alloc_desc_at which would be failing for GSI<NR_IRQS_LEGACY
because the core architecture code has already allocated those for
us. Hence the additional check against NR_IRQS_LEGACY in
xen_allocate_irq_gsi.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
The only caller is xen_allocate_pirq_msi which is also under this
ifdef so this fixes:
drivers/xen/events.c:377: warning: 'find_unbound_pirq' defined but not used
when CONFIG_PCI_MSI=n
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
* 'stable/bug-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen/event: validate irq before get evtchn by irq
xen/fb: fix potential memory leak
xen/fb: fix xenfb suspend/resume race.
xen: disable ACPI NUMA for PV guests
xen/irq: Cleanup the find_unbound_irq
When retrieving the event channel number from irq, the irq
number may not be valid under some conditions.
So far that can be when we suspend/resume and irq ends with -1.
Validate and return sanitized irq and provide diagnostics information.
[v3: added unlikely on the WARN path]
[v2: reworded the commit message]
Signed-off-by: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Gurudas Pai <gurudas.pai@oracle.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
__this_cpu_inc_return reduces code and simplifies code.
Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Use this_cpu_ops to reduce code size and simplify things in various places.
V3->V4:
Move instance of this_cpu_inc_return to a later patchset so that
this patch can be applied without infrastructure changes.
Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The "find_unbound_irq" is a bit unusual - it allocates
virtual IRQ (event channels) in reverse order. This means
starting at the "top" of the available IRQs (nr_irqs) down
to the GSI/MSI IRQs (nr_irqs_gsi). Lets document this and
also make the variables easier to understand.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* '2.6.37-rc4-pvhvm-fixes' of git://xenbits.xen.org/people/sstabellini/linux-pvhvm:
xen: unplug the emulated devices at resume time
xen: fix save/restore for PV on HVM guests with pirq remapping
xen: resume the pv console for hvm guests too
xen: fix MSI setup and teardown for PV on HVM guests
xen: use PHYSDEVOP_get_free_pirq to implement find_unbound_pirq
Allocate irq descs on any NUMA node (we don't care) rather than
specifically node 0, which may not exist.
(At the moment NUMA is meaningless within a domain, so any info
the kernel has is just from an SRAT table we haven't suppressed/disabled.)
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
When remapping MSIs into pirqs for PV on HVM guests, qemu is responsible
for doing the actual mapping and unmapping.
We only give qemu the desired pirq number when we ask to do the mapping
the first time, after that we should be reading back the pirq number
from qemu every time we want to re-enable the MSI.
This fixes a bug in xen_hvm_setup_msi_irqs that manifests itself when
trying to enable the same MSI for the second time: the old MSI to pirq
mapping is still valid at this point but xen_hvm_setup_msi_irqs would
try to assign a new pirq anyway.
A simple way to reproduce this bug is to assign an MSI capable network
card to a PV on HVM guest, if the user brings down the corresponding
ethernet interface and up again, Linux would fail to enable MSIs on the
device.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Use the new hypercall PHYSDEVOP_get_free_pirq to ask Xen to allocate a
pirq. Remove the unsupported PHYSDEVOP_get_nr_pirqs hypercall to get the
amount of pirq available.
This fixes find_unbound_pirq that otherwise would return a number
starting from nr_irqs that might very well be out of range in Xen.
The symptom of this bug is that when you passthrough an MSI capable pci
device to a PV on HVM guest, Linux would fail to enable MSIs on the
device.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
When we allocate a vector for MSI/MSI-X we save away the PIRQ, and the
vector value. When we unmap (de-allocate) the MSI/MSI-X vector(s) we
need to provide the PIRQ and the vector value. What we did instead
was to provide the GSI (which was zero) and the vector value, and we
got these unhappy error messages:
(XEN) irq.c:1575: dom0: pirq 0 not mapped
[ 7.733415] unmap irq failed -22
This patches fixes this and we use the PIRQ value instead of the GSI
value.
CC: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The per-cpu event channel masks can be updated unlocked from multiple
CPUs, so use the locked variant.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
To bind all event channels to CPU#0, it is not sufficient to set all
of its cpu_evtchn_mask[] bits; all other CPUs also need to get their
bits cleared. Otherwise, evtchn_do_upcall() will start handling
interrupts on CPUs they're not intended to run on, which can be
particularly bad for per-CPU ones.
[ linux-2.6.18-xen.hg 7de7453dee36 ]
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
and branch 'for-linus' of git://xenbits.xen.org/people/sstabellini/linux-pvhvm
* 'for-linus' of git://xenbits.xen.org/people/sstabellini/linux-pvhvm:
xen: register xen pci notifier
xen: initialize cpu masks for pv guests in xen_smp_init
xen: add a missing #include to arch/x86/pci/xen.c
xen: mask the MTRR feature from the cpuid
xen: make hvc_xen console work for dom0.
xen: add the direct mapping area for ISA bus access
xen: Initialize xenbus for dom0.
xen: use vcpu_ops to setup cpu masks
xen: map a dummy page for local apic and ioapic in xen_set_fixmap
xen: remap MSIs into pirqs when running as initial domain
xen: remap GSIs as pirqs when running as initial domain
xen: introduce XEN_DOM0 as a silent option
xen: map MSIs into pirqs
xen: support GSI -> pirq remapping in PV on HVM guests
xen: add xen hvm acpi_register_gsi variant
acpi: use indirect call to register gsi in different modes
xen: implement xen_hvm_register_pirq
xen: get the maximum number of pirqs from xen
xen: support pirq != irq
* 'stable/xen-pcifront-0.8.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: (27 commits)
X86/PCI: Remove the dependency on isapnp_disable.
xen: Update Makefile with CONFIG_BLOCK dependency for biomerge.c
MAINTAINERS: Add myself to the Xen Hypervisor Interface and remove Chris Wright.
x86: xen: Sanitse irq handling (part two)
swiotlb-xen: On x86-32 builts, select SWIOTLB instead of depending on it.
MAINTAINERS: Add myself for Xen PCI and Xen SWIOTLB maintainer.
xen/pci: Request ACS when Xen-SWIOTLB is activated.
xen-pcifront: Xen PCI frontend driver.
xenbus: prevent warnings on unhandled enumeration values
xenbus: Xen paravirtualised PCI hotplug support.
xen/x86/PCI: Add support for the Xen PCI subsystem
x86: Introduce x86_msi_ops
msi: Introduce default_[teardown|setup]_msi_irqs with fallback.
x86/PCI: Export pci_walk_bus function.
x86/PCI: make sure _PAGE_IOMAP it set on pci mappings
x86/PCI: Clean up pci_cache_line_size
xen: fix shared irq device passthrough
xen: Provide a variant of xen_poll_irq with timeout.
xen: Find an unbound irq number in reverse order (high to low).
xen: statically initialize cpu_evtchn_mask_p
...
Fix up trivial conflicts in drivers/pci/Makefile
* 'upstream/xenfs' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen:
xen/privcmd: make privcmd visible in domU
xen/privcmd: move remap_domain_mfn_range() to core xen code and export.
privcmd: MMAPBATCH: Fix error handling/reporting
xenbus: export xen_store_interface for xenfs
xen/privcmd: make sure vma is ours before doing anything to it
xen/privcmd: print SIGBUS faults
xen/xenfs: set_page_dirty is supposed to return true if it dirties
xen/privcmd: create address space to allow writable mmaps
xen: add privcmd driver
xen: add variable hypercall caller
xen: add xen_set_domain_pte()
xen: add /proc/xen/xsd_{kva,port} to xenfs
* 'upstream/core' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen: (29 commits)
xen: include xen/xen.h for definition of xen_initial_domain()
xen: use host E820 map for dom0
xen: correctly rebuild mfn list list after migration.
xen: improvements to VIRQ_DEBUG output
xen: set up IRQ before binding virq to evtchn
xen: ensure that all event channels start off bound to VCPU 0
xen/hvc: only notify if we actually sent something
xen: don't add extra_pages for RAM after mem_end
xen: add support for PAT
xen: make sure xen_max_p2m_pfn is up to date
xen: limit extra memory to a certain ratio of base
xen: add extra pages for E820 RAM regions, even if beyond mem_end
xen: make sure xen_extra_mem_start is beyond all non-RAM e820
xen: implement "extra" memory to reserve space for pages not present at boot
xen: Use host-provided E820 map
xen: don't map missing memory
xen: defer building p2m mfn structures until kernel is mapped
xen: add return value to set_phys_to_machine()
xen: convert p2m to a 3 level tree
xen: make install_p2mtop_page() static
...
Fix up trivial conflict in arch/x86/xen/mmu.c, and fix the use of
'reserve_early()' - in the new memblock world order it is now
'memblock_x86_reserve_range()' instead. Pointed out by Jeremy.
Implement xen_create_msi_irq to create an msi and remap it as pirq.
Use xen_create_msi_irq to implement an initial domain specific version
of setup_msi_irqs.
Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Implement xen_register_gsi to setup the correct triggering and polarity
properties of a gsi.
Implement xen_register_pirq to register a particular gsi as pirq and
receive interrupts as events.
Call xen_setup_pirqs to register all the legacy ISA irqs as pirqs.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Map MSIs into pirqs, writing 0 in the MSI vector data field and the pirq
number in the MSI destination id field.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Disable pcifront when running on HVM: it is meant to be used with pv
guests that don't have PCI bus.
Use acpi_register_gsi_xen_hvm to remap GSIs into pirqs.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen_hvm_register_pirq allows the kernel to map a GSI into a Xen pirq and
receive the interrupt as an event channel from that point on.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Use PHYSDEVOP_get_nr_pirqs to get the maximum number of pirqs from xen.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
PHYSDEVOP_map_pirq might return a pirq different from what we asked if
we are running as an HVM guest, so we need to be able to support pirqs
that are different from linux irqs.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* Fix bitmask formatting on 64 bit by specifying correct field widths.
* Output both global and local masked and pending information.
* Indicate in list of pending interrupts whether they are pending in
the L2, masked globally and/or masked locally.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
All event channels startbound to VCPU 0 so ensure that cpu_evtchn_mask
is initialised to reflect this. Otherwise there is a race after registering an
event channel but before the affinity is explicitly set where the event channel
can be delivered. If this happens then the event channel remains pending in the
L1 (evtchn_pending) array but is cleared in L2 (evtchn_pending_sel), this means
the event channel cannot be reraised until another event channel happens to
trigger the same L2 entry on that VCPU.
sizeof(cpu_evtchn_mask(0))==sizeof(unsigned long*) which is not correct, and
causes only the first 32 or 64 event channels (depending on architecture) to be
initially bound to VCPU0. Use sizeof(struct cpu_evtchn_s) instead.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: stable@kernel.org
Change event delivery to:
- mask+clear event in the upcall function
- use handle_fasteoi_irq as the handler
- unmask in the eoi function (and handle migration)
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Thomas Gleixner cleaned up event handling to use the
sparse_irq handling, but the xen-pcifront patches utilized the
old mechanism. This fixes them to work with sparse_irq handling.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The frontend stub lives in arch/x86/pci/xen.c, alongside other
sub-arch PCI init code (e.g. olpc.c).
It provides a mechanism for Xen PCI frontend to setup/destroy
legacy interrupts, MSI/MSI-X, and PCI configuration operations.
[ Impact: add core of Xen PCI support ]
[ v2: Removed the IOMMU code and only focusing on PCI.]
[ v3: removed usage of pci_scan_all_fns as that does not exist]
[ v4: introduced pci_xen value to fix compile warnings]
[ v5: squished fixes+features in one patch, changed Reviewed-by to Ccs]
[ v7: added Acked-by]
Signed-off-by: Alex Nixon <alex.nixon@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Qing He <qing.he@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
In driver/xen/events.c, whether bind_pirq is shareable or not is
determined by desc->action is NULL or not. But in __setup_irq,
startup(irq) is invoked before desc->action is assigned with
new action. So desc->action in startup_irq is always NULL, and
bind_pirq is always not shareable. This results in pt_irq_create_bind
failure when passthrough a device which shares irq to other devices.
This patch doesn't use probing_irq to determine if pirq is shareable
or not, instead set shareable flag in irq_info according to trigger
mode in xen_allocate_pirq. Set level triggered interrupts shareable.
Thus use this flag to set bind_pirq flag accordingly.
[v2: arch/x86/xen/pci.c no more, so file skipped]
Signed-off-by: Weidong Han <weidong.han@intel.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The 'xen_poll_irq_timeout' provides a method to pass in
the poll timeout for IRQs if requested. We also export
those two poll functions as Xen PCI fronted uses them.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
In earlier Xen Linux kernels, the IRQ mapping was a straight 1:1 and the
find_unbound_irq started looking around 256 for open IRQs and up. IRQs
from 0 to 255 were reserved for PCI devices. Previous to this patch,
the 'find_unbound_irq' started looking at get_nr_hw_irqs() number.
For privileged domain where the ACPI information is available that
returns the upper-bound of what the GSIs. For non-privileged PV domains,
where ACPI is no-existent the get_nr_hw_irqs() reports the IRQ_LEGACY (16).
With PCI passthrough enabled, and with PCI cards that have IRQs pinned
to a higher number than 16 we collide with previously allocated IRQs.
Specifically the PCI IRQs collide with the IPI's for Xen functions
(as they are allocated earlier).
For example:
00:00.11 USB Controller: ATI Technologies Inc SB700 USB OHCI1 Controller (prog-if 10 [OHCI])
...
Interrupt: pin A routed to IRQ 18
[root@localhost ~]# cat /proc/interrupts | head
CPU0 CPU1 CPU2
16: 38186 0 0 xen-dyn-virq timer0
17: 149 0 0 xen-dyn-ipi spinlock0
18: 962 0 0 xen-dyn-ipi resched0
and when the USB controller is loaded, the kernel reports:
IRQ handler type mismatch for IRQ 18
current handler: resched0
One way to fix this is to reverse the logic when looking for un-used
IRQ numbers and start with the highest available number. With that,
we would get:
CPU0 CPU1 CPU2
... snip ..
292: 35 0 0 xen-dyn-ipi callfunc0
293: 3992 0 0 xen-dyn-ipi resched0
294: 224 0 0 xen-dyn-ipi spinlock0
295: 57183 0 0 xen-dyn-virq timer0
NMI: 0 0 0 Non-maskable interrupts
.. snip ..
And interrupts for PCI cards are now accessible.
This patch also includes the fix, found by Ian Campbell, titled
"xen: fix off-by-one error in find_unbound_irq."
[v2: Added an explanation in the code]
[v3: Rebased on top of tip/irq/core]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Sometimes cpu_evtchn_mask_p can get used early, before it has been
allocated. Statically initialize it with an initdata version to catch
any early references.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Impact: cleanup
Make pirq show useful information in /proc/interrupts
[v2: Removed the parts for arch/x86/xen/pci.c ]
Signed-off-by: Gerd Hoffmann <kraxel@xeni.home.kraxel.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
