.. which means we can preset of NR_IRQS_LEGACY interrupts using
the 'acpi_get_override_irq' API before this loop.
This means that we can get the IRQ's polarity (and trigger) from either
the ACPI (or MP); or use the default values. This fixes a bug if we did
not have an IOAPIC we would not been able to preset the IRQ's polarity
if the MP table existed.
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>

.. to cut down on the code duplicity.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Not before .. also that code segment starts looking like the HVM one.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In the past we would guard those code segments to be dependent
on CONFIG_XEN_DOM0 (which depends on CONFIG_ACPI) so this patch is
not stricly necessary. But the next patch will merge common
HVM and initial domain code and we want to make sure the CONFIG_ACPI
dependency is preserved - as HVM code does not depend on CONFIG_XEN_DOM0.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Update the out-dated comment at the beginning of the file.
Also provide the copyrights of folks who have been contributing
to this code lately.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The file is hard to read. Move the code around so that
the contents of it follows a uniform format:
 - setup GSIs - PV, HVM, and initial domain case
 - then MSI/MSI-x setup - PV, HVM and then initial domain case.
 - then MSI/MSI-x teardown - same order.
 - lastly, the __init functions in PV, HVM, and initial domain order.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Previously we would check for acpi_sci_override_gsi == gsi every time
a PCI device was enabled. That works during early bootup, but later
on it could lead to triggering unnecessarily the acpi_gsi_to_irq(..) lookup.
The reason is that acpi_sci_override_gsi was declared in __initdata and
after early bootup could contain bogus values.

This patch moves the check for acpi_sci_override_gsi to the
site where the ACPI SCI is preset.

CC: stable@kernel.org
Reported-by: NRaghavendra D Prabhu <rprabhu@wnohang.net>
Tested-by: NRaghavendra D Prabhu <rprabhu@wnohang.net>
[http://lists.xensource.com/archives/html/xen-devel/2011-07/msg00154.html]
Suggested-by: NIan Campbell <ijc@hellion.org.uk>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In the past we would use the GSI value to preset the ACPI SCI
IRQ which worked great as GSI == IRQ:

ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 low level)

While that is most often seen, there are some oddities:

ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 20 low level)

which means that GSI 20 (or pin 20) is to be overriden for IRQ 9.
Our code that presets the interrupt for ACPI SCI however would
use the GSI 20 instead of IRQ 9 ending up with:

xen: sci override: global_irq=20 trigger=0 polarity=1
xen: registering gsi 20 triggering 0 polarity 1
xen: --> pirq=20 -> irq=20
xen: acpi sci 20
.. snip..
calling  acpi_init+0x0/0xbc @ 1
ACPI: SCI (IRQ9) allocation failed
ACPI Exception: AE_NOT_ACQUIRED, Unable to install System Control Interrupt handler (20110413/evevent-119)
ACPI: Unable to start the ACPI Interpreter

as the ACPI interpreter made a call to 'acpi_gsi_to_irq' which got nine.
It used that value to request an IRQ (request_irq) and since that was not
present it failed.

The fix is to recognize that for interrupts that are overriden (in our
case we only care about the ACPI SCI) we should use the IRQ number
to present the IRQ instead of the using GSI. End result is that we get:

xen: sci override: global_irq=20 trigger=0 polarity=1
xen: registering gsi 20 triggering 0 polarity 1
xen: --> pirq=20 -> irq=9 (gsi=9)
xen: acpi sci 9

which fixes the ACPI interpreter failing on startup.

CC: stable@kernel.org
Reported-by: NLiwei <xieliwei@gmail.com>
Tested-by: NLiwei <xieliwei@gmail.com>
[http://lists.xensource.com/archives/html/xen-devel/2011-06/msg01727.html]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

If we have CONFIG_XEN and the other parameters to build an
Linux kernel that is non-privileged, the xen_[find|register|unregister]_
device_domain_owner functions should not be compiled. They should
use the nops defined in arch/x86/include/asm/xen/pci.h instead.

This fixes:

arch/x86/pci/xen.c:496: error: redefinition of ‘xen_find_device_domain_owner’
arch/x86/include/asm/xen/pci.h:25: note: previous definition of ‘xen_find_device_domain_owner’ was here
arch/x86/pci/xen.c:510: error: redefinition of ‘xen_register_device_domain_owner’
arch/x86/include/asm/xen/pci.h:29: note: previous definition of ‘xen_register_device_domain_owner’ was here
arch/x86/pci/xen.c:532: error: redefinition of ‘xen_unregister_device_domain_owner’
arch/x86/include/asm/xen/pci.h:34: note: previous definition of ‘xen_unregister_device_domain_owner’ was here
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reported-by: NRandy Dunlap <randy.dunlap@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>

When the Xen PCI backend is told to enable or disable MSI/MSI-X functions,
the initial domain performs these operations. The initial domain needs
to know which domain (guest) is going to use the PCI device so when it
makes the appropiate hypercall to retrieve the MSI/MSI-X vector it will
also assign the PCI device to the appropiate domain (guest).

This boils down to us needing a mechanism to find, set and unset the domain
id that will be using the device.

[v2: EXPORT_SYMBOL -> EXPORT_SYMBOL_GPL.]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

genirq is switching to a consistent name space for the irq related
functions. Convert x86. Conversion was done with coccinelle.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Following the example set by xen_allocate_pirq_msi and
xen_bind_pirq_msi_to_irq:

xen_allocate_pirq becomes xen_allocate_pirq_gsi and now only allocates
a pirq number and does not bind it.

xen_map_pirq_gsi becomes xen_bind_pirq_gsi_to_irq and binds an
existing pirq.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The function name does not distinguish it from xen_allocate_pirq_msi
(which operates on domU and pvhvm domains rather than dom0).

Hoist domain 0 specific functionality up into the only caller leaving
functionality common to all guest types in xen_bind_pirq_msi_to_irq.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Makes the tail end of this function look even more like
xen_bind_pirq_msi_to_irq.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad 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: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

apic_register_gsi_xen_hvm is a tiny wrapper around
xen_hvm_register_pirq.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

consistent with other similar functions.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

All callers pass this flag so it is pointless.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Fixes:
 CC      arch/x86/pci/xen.o
arch/x86/pci/xen.c:183: warning: 'xen_initdom_setup_msi_irqs' defined but not used
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This happens to not be an issue currently because we take pains to try
to ensure that the GSI-IRQ mapping is 1-1 in a PV guest and that
regular event channels do not clash. However a subsequent patch is
going to break this 1-1 mapping.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>

This code path is only run when an MSI/MSI-X PCI device is passed
in to PV DomU.

In 2.6.37 time-frame we over-wrote the default cleanup handler for
MSI/MSI-X irq->desc to be "xen_teardown_msi_irqs". That function
calls the the xen-pcifront driver which can tell the backend to
cleanup/take back the MSI/MSI-X device.

However, we forgot to continue the process of free-ing the MSI/MSI-X
device resources (irq->desc) in the PV domU side. Which is what
the default cleanup handler: default_teardown_msi_irqs did.

Hence we would leak IRQ descriptors.

Without this patch, doing "rmmod igbvf;modprobe igbvf" multiple
times ends with abandoned IRQ descriptors:

 28:          5  xen-pirq-pcifront-msi-x
 29:          8  xen-pirq-pcifront-msi-x
...
130:         10  xen-pirq-pcifront-msi-x

with the end result of running out of IRQ descriptors.
Reviewed-by: NIan Campbell <Ian.Campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Cleanup code. Cosmetic change to make the code look easier
to read.
Reviewed-by: NIan Campbell <Ian.Campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen_allocate_pirq -> xen_map_pirq_gsi -> PHYSDEVOP_alloc_irq_vector IFF
xen_initial_domain() in addition to the kernel side book-keeping side of
things (set chip and handler, update irq_info etc) whereas
xen_allocate_pirq_msi just does the kernel book keeping.

Also xen_allocate_pirq allocates an IRQ in the 1-1 GSI space whereas
xen_allocate_pirq_msi allocates a dynamic one in the >GSI IRQ space.

All of this is uneccessary as this code path is only executed
when we run as a domU PV guest with an MSI/MSI-X PCI card passed in.
Hence we can jump straight to allocating an dynamic IRQ (and
binding it to the proper PIRQ) and skip the rest.

In short: this change is a cosmetic one.
Reviewed-by: NIan Campbell <Ian.Campbell@citrix.com>
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.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: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Stanse found that xen_setup_msi_irqs leaks memory when
xen_allocate_pirq fails. Free the memory in that fail path.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xensource.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org

Add missing #include <asm/io_apic.h> to arch/x86/pci/xen.c.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

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: NQing He <qing.he@intel.com>
Signed-off-by: NYunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NKonrad 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: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NKonrad 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: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NKonrad 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: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NRafael J. Wysocki <rjw@sisk.pl>

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

This looks to be vestigial dependency that had never been used even
in the original code base (2.6.18) from which this driver
was up-ported. Without this fix, with the CONFIG_ISAPNP, we get this
compile failure:

arch/x86/pci/xen.c: In function 'pci_xen_init':
arch/x86/pci/xen.c:138: error: 'isapnp_disable' undeclared (first use in this function)
arch/x86/pci/xen.c:138: error: (Each undeclared identifier is reported only once
arch/x86/pci/xen.c:138: error: for each function it appears in.)
Reported-by: NLi Zefan <lizf@cn.fujitsu.com>
Tested-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NKonrad 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: NAlex Nixon <alex.nixon@citrix.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NJesse 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