Hi, Igor and Micheal 在 2013-06-06四的 16:33 +0800,li guang写道: > 在 2013-06-06四的 11:13 +0300,Michael S. Tsirkin写道: > > On Thu, Jun 06, 2013 at 11:16:53AM +0800, liguang wrote: > > > v2: > > > 1.remove PIIX4_PROC_BASE operations for cpu hotplug > > > 2.fix wrong description fo cpu-del > > > > > > patch 1 adds ACPI Embedded Controller (EC), > > > refer-to: > > > ACPI SPEC v5 chapter 12 > > > "ACPI Embedded Controller Interface Specification" > > > > > > EC is a standard ACPI device, it plays flexible roles, > > > especially be event carrier, it can pass events between platform > > > and OS, so OS can execute _Qxx method which defined > > > by yourself and query EC's ACPI space which can be a buffer for > > > many purposes > > > > > > here, I want to deliver CPU online/offline event between > > > OS and QEMU for CPU hotplug feature, then we will don't > > > need to "echo 1 > /sys/devices/system/cpu/cpu1/online" > > > again after 'cpu-add' and also for offline to do real cpu > > > removal. > > > > So, it's another channel to the guest. > > Can't qemu-ga do this in userspace, using the existing channel? > > Sorry, I'm not familiar with qemu-ga, > anyway, maybe we don't want to do things like > 'exec("echo 1 > /sys/devices/system/cpu/cpu1/online")' > in userspace. > > BTW, Michael, > do you think if we use EC space to pass info between > platform(QEMU) and OS(PM) instead of 'PIIX4_PROC_BASE' and > something like it can bring some convenience? > for we can directly operate on EC space, we don't have to > register memory regions and ops for them any more, and also, > these regions are mostly not exist in real platforms, > this a motivation that I add this device. >
does this approach have some benefit? > > > > > what I am trying to do is emulated physical addition/removal > > > (like described by linux kernel document for cpu hotplug -- > > > linux-2.6/Documentation/cpu-hotplug.txt) for QEMU. > > > > > > these RFC patches are sent for demo what I am trying to do. > > > > > > the design process simply like following: > > > > > > hotplug > > > qemu::ec::sci -> kernel::ec::gpe::notifier-> > > > kernel::cpu_physic_hotplug::handler->kernel::cpu_up > > > > > > unplug > > > kernel::cpu_down::kernel::cpu_physic_hotplug::handler-> > > > kernel::ec::ec_write->qemu::ec::->qemu::cpu-unplug > > > > > > sorry, I should poll cpu-unplug cmd sent from kernel, > > > but, it's a little trivial, I want do it later. > > > > > > for kernel patches: > > > http://comments.gmane.org/gmane.linux.kernel/1503460 > > > > > > > > > Li Guang (8) > > > acpi: add ACPI Embedded Controller support > > > ich9: add notifer for ec to generate sci > > > ec: add operations for _Qxx events > > > piix4: add notifer for ec to generate sci > > > piix4: add events for cpu hotplug > > > qmp: add 'cpu-del' command > > > pc: add EC qdev init for piix & q35 > > > cpu-hotplug: remove memory regison for cpu hotplug > > > > > > default-configs/x86_64-softmmu.mak | 1 + > > > hw/acpi/Makefile.objs | 1 + > > > hw/acpi/ec.c | 225 > > > ++++++++++++++++++++++++++++++++++++ > > > hw/acpi/ich9.c | 15 +++++++++++++++ > > > hw/acpi/piix4.c | 68 ++++++++++++++ > > > hw/i386/pc.c | 46 ++++++++++++++++++++++++++++-- > > > hw/i386/pc_piix.c | 7 + > > > hw/i386/pc_q35.c | 6 + > > > include/hw/acpi/ec.h | 44 ++++++ > > > include/hw/acpi/ich9.h | 1 + > > > include/hw/boards.h | 5 +++-- > > > include/hw/i386/pc.h | 1 + > > > qapi-schema.json | 13 +++++++++++++ > > > qmp-commands.hx | 23 +++++++++++++++++++++++ > > > qmp.c | 9 +++++++++ > > > 15 files changed, 411 insertions(+), 54 deletions(-) > > > create mode 100644 hw/acpi/ec.c > > > create mode 100644 include/hw/acpi/ec.h > > >