[+cc linux-acpi] On Fri, Jul 26, 2013 at 12:51 AM, Rui Wang <ruiv.wang@xxxxxxxxx> wrote: > Hi Bjorn, > > This was originally the method I used to test hotplug on Intel SDV machines > which are not capable of doing hotplug. I would like to present it here in > case it interests the community, then it can be made available to a wider > range of developers who are working on hotplug. > > I used it to generate desired ACPI events, PCI interrupts, and more. So > things like CPU hotplug, IOH hotplug, memory hotplug, PCI native hotplug, > PCI AER injection can be emulated and tested easily. > > The best thing is that, it doesn't require any modification to those drivers > involved. It works with whatever hardware events that the user can imagine. > Further development in user-space using scripts may help simplify the usage > model and add more software-defined logic on hardware. > > Because it modifies the heart of all h/w access functions, I used Jump Label > to reduce the performance penalty to effectively zero. This is a cool idea. I don't know if you want to merge this upstream, or if it's just a "I found this useful; here it is in case it's useful to you" sort of thing. So the comments below are only relevant if you want to try to merge it upstream. I wouldn't really want all the gunk in drivers/pci/access.c. Most of it isn't related to PCI, and some of it is even x86-specific. It'd be nicer if you could factor it out so just the generic PCI-related things go in drivers/pci. It appears to be implemented only for x86. The MMIO & I/O port parts are x86-specific, but the PCI config stuff should work on any arch. I don't know whether it's worth supporting as a module. It seems like a development aid where building in statically would probably be fine. If it didn't have to work as a module, you wouldn't have to export any symbols. > I tested the performance by repeatedly running lspci, which calls into the > pci access functions. There's no added overhead observed. > > Regards, > Rui Wang > Intel Open Source Technology Center > > Rui Wang (3): > IO Hook: core functions and Register Override > IO Hook: kernel interface to manage the hook > IO Hook: sysfs interface to emulate h/w events > > Documentation/PCI/iohook.txt | 290 +++++++++++++++++ > arch/x86/Kconfig | 7 + > arch/x86/boot/compressed/Makefile | 1 + > arch/x86/include/asm/io.h | 58 ++++- > arch/x86/vdso/Makefile | 2 + > drivers/misc/Kconfig | 1 + > drivers/misc/Makefile | 1 + > drivers/misc/iohook/Kconfig | 5 + > drivers/misc/iohook/Makefile | 1 + > drivers/misc/iohook/iohook.c | 503 +++++++++++++++++++++++++++++ > drivers/pci/access.c | 630 +++++++++++++++++++++++++++++++++++++ > include/linux/reg_ovrd.h | 55 ++++ > 12 files changed, 1552 insertions(+), 2 deletions(-) > create mode 100644 Documentation/PCI/iohook.txt > create mode 100644 drivers/misc/iohook/Kconfig > create mode 100644 drivers/misc/iohook/Makefile > create mode 100644 drivers/misc/iohook/iohook.c > create mode 100644 include/linux/reg_ovrd.h > > -- > 1.7.5.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
