linux/kernel/irq
Marc Zyngier f3b0946d62 genirq/msi: Make sure PCI MSIs are activated early
Bharat Kumar Gogada reported issues with the generic MSI code, where the
end-point ended up with garbage in its MSI configuration (both for the vector
and the message).

It turns out that the two MSI paths in the kernel are doing slightly different
things:

generic MSI: disable MSI -> allocate MSI -> enable MSI -> setup EP
PCI MSI: disable MSI -> allocate MSI -> setup EP -> enable MSI

And it turns out that end-points are allowed to latch the content of the MSI
configuration registers as soon as MSIs are enabled.  In Bharat's case, the
end-point ends up using whatever was there already, which is not what you
want.

In order to make things converge, we introduce a new MSI domain flag
(MSI_FLAG_ACTIVATE_EARLY) that is unconditionally set for PCI/MSI. When set,
this flag forces the programming of the end-point as soon as the MSIs are
allocated.

A consequence of this is that we have an extra activate in irq_startup, but
that should be without much consequence.

tglx: 

 - Several people reported a VMWare regression with PCI/MSI-X passthrough. It
   turns out that the patch also cures that issue.

 - We need to have a look at the MSI disable interrupt path, where we write
   the msg to all zeros without disabling MSI in the PCI device. Is that
   correct?

Fixes: 52f518a3a7 "x86/MSI: Use hierarchical irqdomains to manage MSI interrupts"
Reported-and-tested-by: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>
Reported-and-tested-by: Foster Snowhill <forst@forstwoof.ru>
Reported-by: Matthias Prager <linux@matthiasprager.de>
Reported-by: Jason Taylor <jason.taylor@simplivity.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1468426713-31431-1-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-08-09 09:19:32 +02:00
..
Kconfig genirq: Add GENERIC_IRQ_IPI Kconfig symbol 2016-02-25 10:56:55 +01:00
Makefile genirq: Add a helper to spread an affinity mask for MSI/MSI-X vectors 2016-07-04 12:25:14 +02:00
affinity.c genirq: Add a helper to spread an affinity mask for MSI/MSI-X vectors 2016-07-04 12:25:14 +02:00
autoprobe.c genirq: Handle pending irqs in irq_startup() 2012-02-15 11:56:59 +01:00
chip.c genirq: Add untracked irq handler 2016-06-18 10:00:55 +02:00
cpuhotplug.c genirq: Make the cpuhotplug migration code less noisy 2015-10-22 14:34:57 +02:00
debug.h irq: hide debug macros so they don't collide with others. 2012-04-23 12:30:03 -04:00
devres.c genirq: devres: Fix testing return value of request_any_context_irq() 2015-05-13 10:47:37 +02:00
dummychip.c Merge branch 'linus' into irq/core 2015-06-05 22:25:01 +02:00
generic-chip.c genirq: Add chip_[suspend|resume] PM support to irq_chip 2015-07-27 08:09:38 +02:00
handle.c genirq: Add untracked irq handler 2016-06-18 10:00:55 +02:00
internals.h Merge branch 'irq/for-block' into irq/core 2016-07-04 12:26:05 +02:00
ipi.c genirq: Fix missing irq allocation affinity hint 2016-07-19 10:49:47 +02:00
irqdesc.c genirq: Use affinity hint in irqdesc allocation 2016-07-04 12:25:13 +02:00
irqdomain.c irqdomain: Fix irq_domain_alloc_irqs_recursive() error handling 2016-07-11 17:23:48 +02:00
manage.c Merge branch 'irq/for-block' into irq/core 2016-07-04 12:26:05 +02:00
migration.c genirq: Remove bogus restriction in irq_move_mask_irq() 2015-06-20 19:05:14 +02:00
msi.c genirq/msi: Make sure PCI MSIs are activated early 2016-08-09 09:19:32 +02:00
pm.c Merge branches 'irq-urgent-for-linus' and 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-11-15 09:30:48 -08:00
proc.c Merge branch 'irq/for-block' into irq/core 2016-07-04 12:26:05 +02:00
resend.c genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
settings.h genirq: Add flag to force mask in disable_irq[_nosync]() 2015-10-11 11:33:42 +02:00
spurious.c genirq: Use a common macro to go through the actions list 2016-02-15 00:07:34 +01:00