From 4352b8aee98005853aa63f57d6377282de17a33f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 23 Aug 2026 13:28:57 -0700 Subject: Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ... --- Documentation/virt/acrn/cpuid.rst | 46 +++++++++++++++ Documentation/virt/acrn/index.rst | 12 ++++ Documentation/virt/acrn/introduction.rst | 43 ++++++++++++++ Documentation/virt/acrn/io-request.rst | 97 ++++++++++++++++++++++++++++++++ 4 files changed, 198 insertions(+) create mode 100644 Documentation/virt/acrn/cpuid.rst create mode 100644 Documentation/virt/acrn/index.rst create mode 100644 Documentation/virt/acrn/introduction.rst create mode 100644 Documentation/virt/acrn/io-request.rst (limited to 'Documentation/virt/acrn') diff --git a/Documentation/virt/acrn/cpuid.rst b/Documentation/virt/acrn/cpuid.rst new file mode 100644 index 000000000..65fa4b9c1 --- /dev/null +++ b/Documentation/virt/acrn/cpuid.rst @@ -0,0 +1,46 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============== +ACRN CPUID bits +=============== + +A guest VM running on an ACRN hypervisor can check some of its features using +CPUID. + +ACRN cpuid functions are: + +function: 0x40000000 + +returns:: + + eax = 0x40000010 + ebx = 0x4e524341 + ecx = 0x4e524341 + edx = 0x4e524341 + +Note that this value in ebx, ecx and edx corresponds to the string +"ACRNACRNACRN". The value in eax corresponds to the maximum cpuid function +present in this leaf, and will be updated if more functions are added in the +future. + +function: define ACRN_CPUID_FEATURES (0x40000001) + +returns:: + + ebx, ecx, edx + eax = an OR'ed group of (1 << flag) + +where ``flag`` is defined as below: + +================================= =========== ================================ +flag value meaning +================================= =========== ================================ +ACRN_FEATURE_PRIVILEGED_VM 0 guest VM is a privileged VM +================================= =========== ================================ + +function: 0x40000010 + +returns:: + + ebx, ecx, edx + eax = (Virtual) TSC frequency in kHz. diff --git a/Documentation/virt/acrn/index.rst b/Documentation/virt/acrn/index.rst new file mode 100644 index 000000000..b5f793e73 --- /dev/null +++ b/Documentation/virt/acrn/index.rst @@ -0,0 +1,12 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============== +ACRN Hypervisor +=============== + +.. toctree:: + :maxdepth: 1 + + introduction + io-request + cpuid diff --git a/Documentation/virt/acrn/introduction.rst b/Documentation/virt/acrn/introduction.rst new file mode 100644 index 000000000..f8d081bc0 --- /dev/null +++ b/Documentation/virt/acrn/introduction.rst @@ -0,0 +1,43 @@ +.. SPDX-License-Identifier: GPL-2.0 + +ACRN Hypervisor Introduction +============================ + +The ACRN Hypervisor is a Type 1 hypervisor, running directly on bare-metal +hardware. It has a privileged management VM, called Service VM, to manage User +VMs and do I/O emulation. + +ACRN userspace is an application running in the Service VM that emulates +devices for a User VM based on command line configurations. ACRN Hypervisor +Service Module (HSM) is a kernel module in the Service VM which provides +hypervisor services to the ACRN userspace. + +Below figure shows the architecture. + +:: + + Service VM User VM + +----------------------------+ | +------------------+ + | +--------------+ | | | | + | |ACRN userspace| | | | | + | +--------------+ | | | | + |-----------------ioctl------| | | | ... + |kernel space +----------+ | | | | + | | HSM | | | | Drivers | + | +----------+ | | | | + +--------------------|-------+ | +------------------+ + +---------------------hypercall----------------------------------------+ + | ACRN Hypervisor | + +----------------------------------------------------------------------+ + | Hardware | + +----------------------------------------------------------------------+ + +ACRN userspace allocates memory for the User VM, configures and initializes the +devices used by the User VM, loads the virtual bootloader, initializes the +virtual CPU state and handles I/O request accesses from the User VM. It uses +ioctls to communicate with the HSM. HSM implements hypervisor services by +interacting with the ACRN Hypervisor via hypercalls. HSM exports a char device +interface (/dev/acrn_hsm) to userspace. + +The ACRN hypervisor is open for contribution from anyone. The source repo is +available at https://github.com/projectacrn/acrn-hypervisor. diff --git a/Documentation/virt/acrn/io-request.rst b/Documentation/virt/acrn/io-request.rst new file mode 100644 index 000000000..6cc3ea0fa --- /dev/null +++ b/Documentation/virt/acrn/io-request.rst @@ -0,0 +1,97 @@ +.. SPDX-License-Identifier: GPL-2.0 + +I/O request handling +==================== + +An I/O request of a User VM, which is constructed by the hypervisor, is +distributed by the ACRN Hypervisor Service Module to an I/O client +corresponding to the address range of the I/O request. Details of I/O request +handling are described in the following sections. + +1. I/O request +-------------- + +For each User VM, there is a shared 4-KByte memory region used for I/O requests +communication between the hypervisor and Service VM. An I/O request is a +256-byte structure buffer, which is 'struct acrn_io_request', that is filled by +an I/O handler of the hypervisor when a trapped I/O access happens in a User +VM. ACRN userspace in the Service VM first allocates a 4-KByte page and passes +the GPA (Guest Physical Address) of the buffer to the hypervisor. The buffer is +used as an array of 16 I/O request slots with each I/O request slot being 256 +bytes. This array is indexed by vCPU ID. + +2. I/O clients +-------------- + +An I/O client is responsible for handling User VM I/O requests whose accessed +GPA falls in a certain range. Multiple I/O clients can be associated with each +User VM. There is a special client associated with each User VM, called the +default client, that handles all I/O requests that do not fit into the range of +any other clients. The ACRN userspace acts as the default client for each User +VM. + +Below illustration shows the relationship between I/O requests shared buffer, +I/O requests and I/O clients. + +:: + + +------------------------------------------------------+ + | Service VM | + |+--------------------------------------------------+ | + || +----------------------------------------+ | | + || | shared page ACRN userspace | | | + || | +-----------------+ +------------+ | | | + || +----+->| acrn_io_request |<-+ default | | | | + || | | | +-----------------+ | I/O client | | | | + || | | | | ... | +------------+ | | | + || | | | +-----------------+ | | | + || | +-|--------------------------------------+ | | + ||---|----|-----------------------------------------| | + || | | kernel | | + || | | +----------------------+ | | + || | | | +-------------+ HSM | | | + || | +--------------+ | | | | + || | | | I/O clients | | | | + || | | | | | | | + || | | +-------------+ | | | + || | +----------------------+ | | + |+---|----------------------------------------------+ | + +----|-------------------------------------------------+ + | + +----|-------------------------------------------------+ + | +-+-----------+ | + | | I/O handler | ACRN Hypervisor | + | +-------------+ | + +------------------------------------------------------+ + +3. I/O request state transition +------------------------------- + +The state transitions of an ACRN I/O request are as follows. + +:: + + FREE -> PENDING -> PROCESSING -> COMPLETE -> FREE -> ... + +- FREE: this I/O request slot is empty +- PENDING: a valid I/O request is pending in this slot +- PROCESSING: the I/O request is being processed +- COMPLETE: the I/O request has been processed + +An I/O request in COMPLETE or FREE state is owned by the hypervisor. HSM and +ACRN userspace are in charge of processing the others. + +4. Processing flow of I/O requests +---------------------------------- + +a. The I/O handler of the hypervisor will fill an I/O request with PENDING + state when a trapped I/O access happens in a User VM. +b. The hypervisor makes an upcall, which is a notification interrupt, to + the Service VM. +c. The upcall handler schedules a worker to dispatch I/O requests. +d. The worker looks for the PENDING I/O requests, assigns them to different + registered clients based on the address of the I/O accesses, updates + their state to PROCESSING, and notifies the corresponding client to handle. +e. The notified client handles the assigned I/O requests. +f. The HSM updates I/O requests states to COMPLETE and notifies the hypervisor + of the completion via hypercalls. -- cgit v1.3.1