| Message ID | 20210909230620.511815-3-wuhaotsh@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Handing IPMI for emulating BMC | expand |
On Thu, Sep 09, 2021 at 04:06:14PM -0700, Hao Wu wrote: > From: Havard Skinnemoen <hskinnemoen@google.com> > > This document is an attempt to briefly document the existing IPMI > emulation support on the main processor. It provides the necessary > background for the BMC-side IPMI emulation proposed by the next patch. I'm good with this for the most part. One nit inline below. This block diagrams depend on the previous patch. > > Signed-off-by: Havard Skinnemoen <hskinnemoen@google.com> > Signed-off-by: Hao Wu <wuhaotsh@google.com> > --- > docs/specs/index.rst | 1 + > docs/specs/ipmi.rst | 100 +++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 101 insertions(+) > create mode 100644 docs/specs/ipmi.rst > > diff --git a/docs/specs/index.rst b/docs/specs/index.rst > index 65e9663916..1b5d177d53 100644 > --- a/docs/specs/index.rst > +++ b/docs/specs/index.rst > @@ -11,6 +11,7 @@ guest hardware that is specific to QEMU. > ppc-spapr-xive > ppc-spapr-numa > acpi_hw_reduced_hotplug > + ipmi > tpm > acpi_hest_ghes > acpi_cpu_hotplug > diff --git a/docs/specs/ipmi.rst b/docs/specs/ipmi.rst > new file mode 100644 > index 0000000000..adb098b53d > --- /dev/null > +++ b/docs/specs/ipmi.rst > @@ -0,0 +1,100 @@ > +===================== > +IPMI device emulation > +===================== > + > +QEMU supports emulating many types of machines. This includes machines that may > +serve as the main processor in an IPMI system, e.g. x86 or POWER server > +processors, as well as machines emulating ARM-based Baseband Management > +Controllers (BMCs), e.g. AST2xxx or NPCM7xxx systems-on-chip. > + > +Main processor emulation > +======================== > + > +A server platform may include one of the following system interfaces for > +communicating with a BMC: > + > +* A Keyboard Controller Style (KCS) Interface, accessible via ISA > + (``isa-ipmi-kcs``) or PCI (``pci-ipmi-kcs``). > +* A Block Transfer (BT) Interface, accessible via ISA (``isa-ipmi-bt``) or PCI > + (``pci-ipmi-bt``). > +* An SMBus System Interface (SSIF; ``smbus-ipmi``). > + > +These interfaces can all be emulated by QEMU. To emulate the behavior of the > +BMC, the messaging interface emulators use one of the following backends: > + > +* A BMC simulator running within the QEMU process (``ipmi-bmc-sim``). > +* An external BMC simulator or emulator, connected over a chardev > + (``ipmi-bmc-extern``). `ipmi_sim > + <https://github.com/wrouesnel/openipmi/blob/master/lanserv/README.ipmi_sim>`_ Here, and in the other reference below, can you reference the official repository instead of your own? > + from OpenIPMI is an example external BMC emulator. > + > +The following diagram shows how these entities relate to each other. > + > +.. blockdiag:: > + > + blockdiag main_processor_ipmi { > + orientation = portrait > + default_group_color = "none"; > + class msgif [color = lightblue]; > + class bmc [color = salmon]; > + > + ipmi_sim [color="aquamarine", label="External BMC"] > + ipmi-bmc-extern <-> ipmi_sim [label="chardev"]; > + > + group { > + orientation = portrait > + > + ipmi-interface <-> ipmi-bmc; > + > + group { > + orientation = portrait > + > + ipmi-interface [class = "msgif"]; > + isa-ipmi-kcs [class="msgif", stacked]; > + > + ipmi-interface <- isa-ipmi-kcs [hstyle = generalization]; > + } > + > + > + group { > + orientation = portrait > + > + ipmi-bmc [class = "bmc"]; > + ipmi-bmc-sim [class="bmc"]; > + ipmi-bmc-extern [class="bmc"]; > + > + ipmi-bmc <- ipmi-bmc-sim [hstyle = generalization]; > + ipmi-bmc <- ipmi-bmc-extern [hstyle = generalization]; > + } > + > + } > + } > + > +IPMI System Interfaces > +---------------------- > + > +The system software running on the main processor may use a *system interface* > +to communicate with the BMC. These are hardware devices attached to an ISA, PCI > +or i2c bus, and in QEMU, they all need to implement ``ipmi-interface``. > +This allows a BMC implementation to interact with the system interface in a > +standard way. > + > +IPMI BMC > +-------- > + > +The system interface devices delegate emulation of BMC behavior to a BMC > +device, that is a subclass of ``ipmi-bmc``. This type of device is called > +a BMC because that's what it looks like to the main processor guest software. > + > +The BMC behavior may be simulated within the qemu process (``ipmi-bmc-sim``) or > +further delegated to an external emulator, or a real BMC. The > +``ipmi-bmc-extern`` device has a required ``chardev`` property which specifies > +the communications channel to the external BMC. > + > +Wire protocol > +============= > + > +The wire protocol used between ``ipmi-bmc-extern`` and the external BMC > +emulator is defined by `README.vm > +<https://github.com/wrouesnel/openipmi/blob/master/lanserv/README.vm>`_ from > +the OpenIPMI project. > -- > 2.33.0.309.g3052b89438-goog >
diff --git a/docs/specs/index.rst b/docs/specs/index.rst index 65e9663916..1b5d177d53 100644 --- a/docs/specs/index.rst +++ b/docs/specs/index.rst @@ -11,6 +11,7 @@ guest hardware that is specific to QEMU. ppc-spapr-xive ppc-spapr-numa acpi_hw_reduced_hotplug + ipmi tpm acpi_hest_ghes acpi_cpu_hotplug diff --git a/docs/specs/ipmi.rst b/docs/specs/ipmi.rst new file mode 100644 index 0000000000..adb098b53d --- /dev/null +++ b/docs/specs/ipmi.rst @@ -0,0 +1,100 @@ +===================== +IPMI device emulation +===================== + +QEMU supports emulating many types of machines. This includes machines that may +serve as the main processor in an IPMI system, e.g. x86 or POWER server +processors, as well as machines emulating ARM-based Baseband Management +Controllers (BMCs), e.g. AST2xxx or NPCM7xxx systems-on-chip. + +Main processor emulation +======================== + +A server platform may include one of the following system interfaces for +communicating with a BMC: + +* A Keyboard Controller Style (KCS) Interface, accessible via ISA + (``isa-ipmi-kcs``) or PCI (``pci-ipmi-kcs``). +* A Block Transfer (BT) Interface, accessible via ISA (``isa-ipmi-bt``) or PCI + (``pci-ipmi-bt``). +* An SMBus System Interface (SSIF; ``smbus-ipmi``). + +These interfaces can all be emulated by QEMU. To emulate the behavior of the +BMC, the messaging interface emulators use one of the following backends: + +* A BMC simulator running within the QEMU process (``ipmi-bmc-sim``). +* An external BMC simulator or emulator, connected over a chardev + (``ipmi-bmc-extern``). `ipmi_sim + <https://github.com/wrouesnel/openipmi/blob/master/lanserv/README.ipmi_sim>`_ + from OpenIPMI is an example external BMC emulator. + +The following diagram shows how these entities relate to each other. + +.. blockdiag:: + + blockdiag main_processor_ipmi { + orientation = portrait + default_group_color = "none"; + class msgif [color = lightblue]; + class bmc [color = salmon]; + + ipmi_sim [color="aquamarine", label="External BMC"] + ipmi-bmc-extern <-> ipmi_sim [label="chardev"]; + + group { + orientation = portrait + + ipmi-interface <-> ipmi-bmc; + + group { + orientation = portrait + + ipmi-interface [class = "msgif"]; + isa-ipmi-kcs [class="msgif", stacked]; + + ipmi-interface <- isa-ipmi-kcs [hstyle = generalization]; + } + + + group { + orientation = portrait + + ipmi-bmc [class = "bmc"]; + ipmi-bmc-sim [class="bmc"]; + ipmi-bmc-extern [class="bmc"]; + + ipmi-bmc <- ipmi-bmc-sim [hstyle = generalization]; + ipmi-bmc <- ipmi-bmc-extern [hstyle = generalization]; + } + + } + } + +IPMI System Interfaces +---------------------- + +The system software running on the main processor may use a *system interface* +to communicate with the BMC. These are hardware devices attached to an ISA, PCI +or i2c bus, and in QEMU, they all need to implement ``ipmi-interface``. +This allows a BMC implementation to interact with the system interface in a +standard way. + +IPMI BMC +-------- + +The system interface devices delegate emulation of BMC behavior to a BMC +device, that is a subclass of ``ipmi-bmc``. This type of device is called +a BMC because that's what it looks like to the main processor guest software. + +The BMC behavior may be simulated within the qemu process (``ipmi-bmc-sim``) or +further delegated to an external emulator, or a real BMC. The +``ipmi-bmc-extern`` device has a required ``chardev`` property which specifies +the communications channel to the external BMC. + +Wire protocol +============= + +The wire protocol used between ``ipmi-bmc-extern`` and the external BMC +emulator is defined by `README.vm +<https://github.com/wrouesnel/openipmi/blob/master/lanserv/README.vm>`_ from +the OpenIPMI project.