linux.git/include/uapi/linux/acrn.h, branch v6.6.132

virt: acrn: Mark the uuid field as unused

2022-11-23T18:55:22+00:00

After the commits for userspace (see Link tags below) the uuid field
is not being used in the ACRN code. Update kernel to reflect these
changes, i.e. do the following:
- adding a comment explaining that it's not used anymore
- replacing the specific type by a raw buffer
- updating the example code accordingly

The advertised field confused users and actually never been used.
So the wrong part here is that kernel puts something which userspace
never used and hence this may confuse a reader of this code.

Note, that there is only a single tool that had been prepared a year
ago for these forthcoming changes in the kernel.

Link: https://github.com/projectacrn/acrn-hypervisor/commit/da0d24326ed6
Link: https://github.com/projectacrn/acrn-hypervisor/commit/bb0327e70097
Signed-off-by: Andy Shevchenko 
Acked-by: Rafael J. Wysocki 
Link: https://lore.kernel.org/r/20221116162956.72658-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

virt: acrn: Introduce interfaces for virtual device creating/destroying

2021-10-05T14:14:10+00:00

The ACRN hypervisor can emulate a virtual device within hypervisor for a
Guest VM. The emulated virtual device can work without the ACRN
userspace after creation. The hypervisor do the emulation of that device.

To support the virtual device creating/destroying, HSM provides the
following ioctls:
  - ACRN_IOCTL_CREATE_VDEV
    Pass data struct acrn_vdev from userspace to the hypervisor, and inform
    the hypervisor to create a virtual device for a User VM.
  - ACRN_IOCTL_DESTROY_VDEV
    Pass data struct acrn_vdev from userspace to the hypervisor, and inform
    the hypervisor to destroy a virtual device of a User VM.

These new APIs will be used by user space code vm_add_hv_vdev and
vm_remove_hv_vdev in
https://github.com/projectacrn/acrn-hypervisor/blob/master/devicemodel/core/vmmapi.c

Signed-off-by: Shuo Liu 
Signed-off-by: Fei Li 
Link: https://lore.kernel.org/r/20210923084128.18902-3-fei1.li@intel.com
Signed-off-by: Greg Kroah-Hartman

virt: acrn: Introduce interfaces for MMIO device passthrough

2021-10-05T14:14:10+00:00

MMIO device passthrough enables an OS in a virtual machine to directly
access a MMIO device in the host. It promises almost the native
performance, which is required in performance-critical scenarios of
ACRN.

HSM provides the following ioctls:
  - Assign - ACRN_IOCTL_ASSIGN_MMIODEV
    Pass data struct acrn_mmiodev from userspace to the hypervisor, and
    inform the hypervisor to assign a MMIO device to a User VM.

  - De-assign - ACRN_IOCTL_DEASSIGN_PCIDEV
    Pass data struct acrn_mmiodev from userspace to the hypervisor, and
    inform the hypervisor to de-assign a MMIO device from a User VM.

These new APIs will be used by user space code vm_assign_mmiodev and
vm_deassign_mmiodev in
https://github.com/projectacrn/acrn-hypervisor/blob/master/devicemodel/core/vmmapi.c

Signed-off-by: Shuo Liu 
Signed-off-by: Fei Li 
Link: https://lore.kernel.org/r/20210923084128.18902-2-fei1.li@intel.com
Signed-off-by: Greg Kroah-Hartman

virt: acrn: Introduce irqfd

2021-02-09T09:58:19+00:00

irqfd is a mechanism to inject a specific interrupt to a User VM using a
decoupled eventfd mechanism.

Vhost is a kernel-level virtio server which uses eventfd for interrupt
injection. To support vhost on ACRN, irqfd is introduced in HSM.

HSM provides ioctls to associate a virtual Message Signaled Interrupt
(MSI) with an eventfd. The corresponding virtual MSI will be injected
into a User VM once the eventfd got signal.

Cc: Zhi Wang 
Cc: Zhenyu Wang 
Cc: Yu Wang 
Cc: Reinette Chatre 
Cc: Greg Kroah-Hartman 
Reviewed-by: Zhi Wang 
Reviewed-by: Reinette Chatre 
Signed-off-by: Shuo Liu 
Link: https://lore.kernel.org/r/20210207031040.49576-17-shuo.a.liu@intel.com
Signed-off-by: Greg Kroah-Hartman

virt: acrn: Introduce ioeventfd

2021-02-09T09:58:19+00:00

ioeventfd is a mechanism to register PIO/MMIO regions to trigger an
eventfd signal when written to by a User VM. ACRN userspace can register
any arbitrary I/O address with a corresponding eventfd and then pass the
eventfd to a specific end-point of interest for handling.

Vhost is a kernel-level virtio server which uses eventfd for signalling.
To support vhost on ACRN, ioeventfd is introduced in HSM.

A new I/O client dedicated to ioeventfd is associated with a User VM
during VM creation. HSM provides ioctls to associate an I/O region with
a eventfd. The I/O client signals a eventfd once its corresponding I/O
region is matched with an I/O request.

Cc: Zhi Wang 
Cc: Zhenyu Wang 
Cc: Yu Wang 
Cc: Reinette Chatre 
Cc: Greg Kroah-Hartman 
Reviewed-by: Zhi Wang 
Reviewed-by: Reinette Chatre 
Signed-off-by: Shuo Liu 
Link: https://lore.kernel.org/r/20210207031040.49576-16-shuo.a.liu@intel.com
Signed-off-by: Greg Kroah-Hartman

virt: acrn: Introduce interfaces to query C-states and P-states allowed by hypervisor

2021-02-09T09:58:19+00:00

The C-states and P-states data are used to support CPU power management.
The hypervisor controls C-states and P-states for a User VM.

ACRN userspace need to query the data from the hypervisor to build ACPI
tables for a User VM.

HSM provides ioctls for ACRN userspace to query C-states and P-states
data obtained from the hypervisor.

Cc: Zhi Wang 
Cc: Zhenyu Wang 
Cc: Yu Wang 
Cc: Reinette Chatre 
Cc: Greg Kroah-Hartman 
Reviewed-by: Zhi Wang 
Reviewed-by: Reinette Chatre 
Signed-off-by: Shuo Liu 
Link: https://lore.kernel.org/r/20210207031040.49576-14-shuo.a.liu@intel.com
Signed-off-by: Greg Kroah-Hartman

virt: acrn: Introduce interrupt injection interfaces

2021-02-09T09:58:19+00:00

ACRN userspace need to inject virtual interrupts into a User VM in
devices emulation.

HSM needs provide interfaces to do so.

Introduce following interrupt injection interfaces:

ioctl ACRN_IOCTL_SET_IRQLINE:
  Pass data from userspace to the hypervisor, and inform the hypervisor
  to inject a virtual IOAPIC GSI interrupt to a User VM.

ioctl ACRN_IOCTL_INJECT_MSI:
  Pass data struct acrn_msi_entry from userspace to the hypervisor, and
  inform the hypervisor to inject a virtual MSI to a User VM.

ioctl ACRN_IOCTL_VM_INTR_MONITOR:
  Set a 4-Kbyte aligned shared page for statistics information of
  interrupts of a User VM.

Cc: Zhi Wang 
Cc: Zhenyu Wang 
Cc: Yu Wang 
Cc: Reinette Chatre 
Cc: Greg Kroah-Hartman 
Reviewed-by: Zhi Wang 
Reviewed-by: Reinette Chatre 
Signed-off-by: Shuo Liu 
Link: https://lore.kernel.org/r/20210207031040.49576-13-shuo.a.liu@intel.com
Signed-off-by: Greg Kroah-Hartman

virt: acrn: Introduce interfaces for PCI device passthrough

2021-02-09T09:58:19+00:00

PCI device passthrough enables an OS in a virtual machine to directly
access a PCI device in the host. It promises almost the native
performance, which is required in performance-critical scenarios of
ACRN.

HSM provides the following ioctls:
 - Assign - ACRN_IOCTL_ASSIGN_PCIDEV
   Pass data struct acrn_pcidev from userspace to the hypervisor, and
   inform the hypervisor to assign a PCI device to a User VM.

 - De-assign - ACRN_IOCTL_DEASSIGN_PCIDEV
   Pass data struct acrn_pcidev from userspace to the hypervisor, and
   inform the hypervisor to de-assign a PCI device from a User VM.

 - Set a interrupt of a passthrough device - ACRN_IOCTL_SET_PTDEV_INTR
   Pass data struct acrn_ptdev_irq from userspace to the hypervisor,
   and inform the hypervisor to map a INTx interrupt of passthrough
   device of User VM.

 - Reset passthrough device interrupt - ACRN_IOCTL_RESET_PTDEV_INTR
   Pass data struct acrn_ptdev_irq from userspace to the hypervisor,
   and inform the hypervisor to unmap a INTx interrupt of passthrough
   device of User VM.

Cc: Zhi Wang 
Cc: Zhenyu Wang 
Cc: Yu Wang 
Cc: Reinette Chatre 
Cc: Greg Kroah-Hartman 
Reviewed-by: Zhi Wang 
Reviewed-by: Reinette Chatre 
Signed-off-by: Shuo Liu 
Link: https://lore.kernel.org/r/20210207031040.49576-12-shuo.a.liu@intel.com
Signed-off-by: Greg Kroah-Hartman

virt: acrn: Introduce PCI configuration space PIO accesses combiner

2021-02-09T09:58:19+00:00

A User VM can access its virtual PCI configuration spaces via port IO
approach, which has two following steps:
 1) writes address into port 0xCF8
 2) put/get data in/from port 0xCFC

To distribute a complete PCI configuration space access one time, HSM
need to combine such two accesses together.

Combine two paired PIO I/O requests into one PCI I/O request and
continue the I/O request distribution.

Cc: Greg Kroah-Hartman 
Reviewed-by: Reinette Chatre 
Signed-off-by: Shuo Liu 
Link: https://lore.kernel.org/r/20210207031040.49576-11-shuo.a.liu@intel.com
Signed-off-by: Greg Kroah-Hartman

virt: acrn: Introduce I/O request management

2021-02-09T09:58:19+00:00

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.

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.

An I/O client, which is 'struct acrn_ioreq_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 I/O clients. The ACRN userspace acts as the default client for
each User VM.

The state transitions of a 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.

The processing flow of I/O requests are listed as following:

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.

Cc: Davidlohr Bueso 
Cc: Zhi Wang 
Cc: Zhenyu Wang 
Cc: Yu Wang 
Cc: Reinette Chatre 
Cc: Greg Kroah-Hartman 
Reviewed-by: Zhi Wang 
Reviewed-by: Reinette Chatre 
Acked-by: Davidlohr Bueso 
Signed-off-by: Shuo Liu 
Link: https://lore.kernel.org/r/20210207031040.49576-10-shuo.a.liu@intel.com
Signed-off-by: Greg Kroah-Hartman