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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-23 20:53:53 +08:00
linux-next/arch/powerpc
Nathan Fontenot 999e2dadb6 powerpc/pseries: Create new device hotplug entry point
The current hotplug (or dlpar) of devices (the process is generally the
same for memory, cpu, and pci) on PowerVM systems is initiated
from the HMC, which communicates the request to the partitions through
the RSCT framework. The RSCT framework then invokes the drmgr command.
The drmgr command performs the hotplug operation by doing some pieces,
such as most of the rtas calls and device tree parsing, in userspace
and make requests to the kernel to online/offline the device, update the
device tree and add/remove the device.

For PowerKVM the approach for device hotplug is to follow what is currently
being done for pci hotplug. A hotplug request is initiated from the host.
QEMU then generates an EPOW interrupt to the guest which causes the guest
to make the rtas,check-exception call. In QEMU, the rtas,check-exception call
returns a rtas hotplug event to the guest.

Please note that the current pci hotplug path for PowerKVM involves the
kernel receiving the rtas hotplug event, passing it to rtas_errd in
userspace, and having rtas_errd invoke drmgr. The drmgr command then
handles the request as described above for PowerVM systems.

There is no need for this circuitous route, we should just handle the entire
hotplug of devices in the kernel. What I am planning is to enable this
by moving the code to handle hotplug from drmgr into the kernel to
provide a single path for handling device hotplug for both PowerVM and
PowerKVM systems. This patch provides the common iframework and entry point.
For PowerKVM a future update to the kernel rtas code will recognize rtas
hotplug events returned from rtas,check-exception calls and use the common
entry point to handle hotplug of the device.

For PowerVM systems, This patch creates /sys/kernel/dlpar that can be
used by the drmgr command to initiate hotplug requests. In order to do
this a string of the format "<resource> <action> <id_type> <id>" is
written to this file. The string consists of a resource (cpu, memory, pci,
phb), an action (add or remove), an id_type (count, drc index, drc name),
and the corresponding id. The kernel will parse the string and create a
rtas hotplug section that can be passed to the common entry point for
handling hotplug requests.

It should be noted that there is no chance of updating how we receive
hotplug (dlpar) requests from the HMC on PowerVM systems.

Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2015-03-17 11:02:58 +11:00
..
boot powerpc: dts: pq3/85xx: Fix GPIO address 2015-01-29 23:04:32 -06:00
configs The clock framework changes for 3.20 contain the usual driver additions, 2015-02-21 12:30:30 -08:00
crypto crypto: add missing crypto module aliases 2015-01-13 22:29:11 +11:00
include powerpc/pseries: Define rtas hotplug event sections 2015-03-17 10:57:44 +11:00
kernel powerpc/iommu: Remove IOMMU device references via bus notifier 2015-03-04 13:19:33 +11:00
kvm Tighten rules for ACCESS_ONCE 2015-02-14 10:54:28 -08:00
lib powerpc/lib: Makefile, use obj64-y to consolidate 64-bit rules 2015-01-28 15:00:24 +11:00
math-emu powerpc: Correct emulated mtfsf instruction 2014-04-07 10:33:11 +10:00
mm powerpc: drop _PAGE_FILE and pte_file()-related helpers 2015-02-16 17:56:05 -08:00
net module: remove mod arg from module_free, rename module_memfree(). 2015-01-20 11:38:33 +10:30
oprofile powerpc updates for 3.19 2014-12-11 17:48:14 -08:00
perf Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/scottwood/linux into next 2015-02-04 12:03:21 +11:00
platforms powerpc/pseries: Create new device hotplug entry point 2015-03-17 11:02:58 +11:00
sysdev powerpc: use %*pb[l] to print bitmaps including cpumasks and nodemasks 2015-02-13 21:21:36 -08:00
xmon powerpc updates for 3.20 2015-02-11 18:15:38 -08:00
Kconfig powerpc/mm: fix undefined reference to `.__kernel_map_pages' on FSL PPC64 2015-01-28 14:22:22 +11:00
Kconfig.debug Patch queue for ppc - 2014-08-01 2014-08-05 09:58:11 +02:00
Makefile kbuild: do not add $(call ...) to invoke cc-version or cc-fullversion 2015-01-09 17:25:44 +01:00
relocs_check.pl Fix warning typo "CONFIG_RELCOATABLE" 2013-05-29 15:11:30 +02:00