freebsd-dev/sys/x86
John Baldwin be0319fd19 Add a tunable to disable migration of MSI-X interrupts.
The new 'machdep.disable_msix_migration' tunable can be set to 1 to
disable migration of MSI-X interrupts.

Xen versions prior to 4.6.0 do not properly handle updates to MSI-X
table entries after the initial write.  In particular, the operation
to unmask a table entry after updating it during migration is not
propagated to the "real" table for passthrough devices causing the
interrupt to remain masked.  At least some systems in EC2 are
affected by this bug when using SRIOV.  The tunable can be set in
loader.conf as a workaround.

Submitted by:	Jeremiah Lott <jlott@averesystems.com> (original patch)
Approved by:	re (marius)
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D6947
2016-06-24 22:49:32 +00:00
..
acpica Use M_NOWAIT when allocating memory for the ACPI wakeup handler. 2016-06-23 19:24:38 +00:00
bios
cpufreq Cleanup unnecessary semicolons from the kernel. 2016-04-10 23:07:00 +00:00
include Implement _ALIGN() using internal integer types. 2016-05-31 13:31:19 +00:00
iommu sys: use our roundup2/rounddown2() macros when param.h is available. 2016-04-21 19:57:40 +00:00
isa Add an EARLY_AP_STARTUP option to start APs earlier during boot. 2016-05-14 18:22:52 +00:00
pci
x86 Add a tunable to disable migration of MSI-X interrupts. 2016-06-24 22:49:32 +00:00
xen Remove misc NULL checks after M_WAITOK allocations. 2016-05-10 10:26:07 +00:00