Merged PR 16154870: MsvmPkg: Advertise emulated IPMI/SEL BMC to the guest (SMBIOS Type 38 + ACPI IPI0001), gated on PcdIpmiEnabled - #97
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…uest (SMBIOS Type 38 + ACPI IPI0001), gated on PcdIpmiEnabled Advertise the emulated IPMI BMC (implemented in the HCL paravisor, KCS interface at I/O ports `0xCA2`/`0xCA3`) to the guest OS so it can discover and bind to it. Two discovery mechanisms are added, both gated on a new `PcdIpmiEnabled` that the host sets via `UEFI_CONFIG_FLAGS.IpmiEnabled`. Default is **off** (`FALSE`) — no behavior change unless the host enables IPMI. 📄 **Architecture:** [Arch: IPMI/SEL LegacyHCL](https://microsoft.sharepoint.com/:fl:/s/a363cb82-c5cc-491f-a46b-8212ce6d7288/IQCescwvmOvSSYU11NT9Z3eOAf-MEoE8Z3HiB0yscIXPNr8?e=cNj8KF) > Paired with the [**OS Repo Legacy HCL** PR](https://microsoft.visualstudio.com/OS/_git/os.2020/pullrequest/15989323). > Please review the two draft PRs together.. The BMC/SEL emulator lives in the LegacyHCL/OpenHCL paravisor; the guest records System Event Log (SEL) entries over KCS, which the host logs for UVM diagnosability. The two guest OSes discover an IPMI BMC differently: - **Linux** (`ipmi_si`) reads **SMBIOS Type 38** (IPMI Device Information). - **Windows** (`ipmidrv`) binds to an **ACPI** node `ACPI\IPI0001` created from a DSDT namespace device. Firmware previously advertised neither, so neither guest OS auto-bound its IPMI driver. 1. **SMBIOS Type 38** — emit an IPMI Device Information structure (Interface Type = KCS `0x01`, Base Address `0xCA2` I/O space, Spec Rev 2.0) from `SmbiosPlatformDxe`, gated on `PcdIpmiEnabled`. 2. **ACPI IPI0001** — add a DSDT device `\_SB.IPMI` (`_HID "IPI0001"`, `_IFT` = KCS, `_SRV` = IPMI 2.0, `_CRS` = I/O `0xCA2`–`0xCA3`), conditionally declared via a runtime `ICFG` flag in the DSDT data blob, mirroring the existing VMBus `VCFG` pattern. `UEFI_CONFIG_FLAGS.IpmiEnabled` (host) → `PlatformPei/Config.c` → `PcdSetBoolS(PcdIpmiEnabled)` → consumed by `SmbiosPlatformDxe` (Type 38) and `AcpiPlatformDxe` (DSDT `ICFG`). - `MsvmPkg/Include/BiosInterface.h` — add `IpmiEnabled : 1` to `UEFI_CONFIG_FLAGS`. - `MsvmPkg/MsvmPkg.dec`, `MsvmPkg/MsvmPkgX64.dsc` — declare `PcdIpmiEnabled` (default `FALSE`). - `MsvmPkg/PlatformPei/Config.c`, `PlatformPei/PlatformPei.inf` — map the config flag → PCD (PEI sets it). - `MsvmPkg/SmbiosPlatformDxe/SmbiosPlatform.c`, `SmbiosPlatformDxe.inf` — `AddIpmiDeviceInformation()` (Type 38); consumes PCD. - `MsvmPkg/AcpiTables/Dsdt.asl` — `ICFG` field + `If(ICFG>0)` IPI0001 device block. - `MsvmPkg/AcpiPlatformDxe/Dsdt.c`, `AcpiPlatformDxe.inf` — populate `IpmiEnabled` in the DSDT data blob from the PCD. - `MsvmX64` builds clean (`stuart_build`). - End-to-end on a nested VM with IPMI enabled: guest shows `ACPI\IPI0001\0` ("Microsoft Generic IPMI Compliant Device"), `ipmidrv` Running, `Microsoft_IPMI` WMI present; SMBIOS scan shows Type 38. Get Device ID and Add SEL Entry succeed over KCS, and SEL entries reach the host ETW provider. - With `PcdIpmiEnabled=FALSE` (default): neither structure is emitted — no behavior change.
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Advertise the emulated IPMI BMC (implemented in the HCL paravisor, KCS interface at I/O ports
0xCA2/0xCA3) to the guest OS so it can discover and bind to it. Two discovery mechanisms are added, both gated on a newPcdIpmiEnabledthat the host sets viaUEFI_CONFIG_FLAGS.IpmiEnabled. Default is off (FALSE) — no behavior change unless the host enables IPMI.The BMC/SEL emulator lives in the LegacyHCL/OpenHCL paravisor; the guest records System Event Log (SEL) entries over KCS, which the host logs for UVM diagnosability. The two guest OSes discover an IPMI BMC differently:
ipmi_si) reads SMBIOS Type 38 (IPMI Device Information).ipmidrv) binds to an ACPI nodeACPI\IPI0001created from a DSDT namespace device.Firmware previously advertised neither, so neither guest OS auto-bound its IPMI driver.
0x01, Base Address0xCA2I/O space, Spec Rev 2.0) fromSmbiosPlatformDxe, gated onPcdIpmiEnabled.\_SB.IPMI(_HID "IPI0001",_IFT= KCS,_SRV= IPMI 2.0,_CRS= I/O0xCA2–0xCA3), conditionally declared via a runtimeICFGflag in the DSDT data blob, mirroring the existing VMBusVCFGpattern.UEFI_CONFIG_FLAGS.IpmiEnabled(host) →PlatformPei/Config.c→PcdSetBoolS(PcdIpmiEnabled)→ consumed bySmbiosPlatformDxe(Type 38) andAcpiPlatformDxe(DSDTICFG).MsvmPkg/Include/BiosInterface.h— addIpmiEnabled : 1toUEFI_CONFIG_FLAGS.MsvmPkg/MsvmPkg.dec,MsvmPkg/MsvmPkgX64.dsc— declarePcdIpmiEnabled(defaultFALSE).MsvmPkg/PlatformPei/Config.c,PlatformPei/PlatformPei.inf— map the config flag → PCD (PEI sets it).MsvmPkg/SmbiosPlatformDxe/SmbiosPlatform.c,SmbiosPlatformDxe.inf—AddIpmiDeviceInformation()(Type 38); consumes PCD.MsvmPkg/AcpiTables/Dsdt.asl—ICFGfield +If(ICFG>0)IPI0001 device block.MsvmPkg/AcpiPlatformDxe/Dsdt.c,AcpiPlatformDxe.inf— populateIpmiEnabledin the DSDT data blob from the PCD.MsvmX64builds clean (stuart_build).End-to-end on a nested VM with IPMI enabled: guest shows
ACPI\IPI0001\0("Microsoft Generic IPMI Compliant Device"),ipmidrvRunning,Microsoft_IPMIWMI present; SMBIOS scan shows Type 38. Get Device ID and Add SEL Entry succeed over KCS, and SEL entries reach the host ETW provider.With
PcdIpmiEnabled=FALSE(default): neither structure is emitted — no behavior change.