212 lines
6.8 KiB
C
212 lines
6.8 KiB
C
/* SPDX-License-Identifier: BSD-3-Clause */
|
|
/*
|
|
* Virtio Mem Device
|
|
*
|
|
* Copyright Red Hat, Inc. 2020
|
|
*
|
|
* Authors:
|
|
* David Hildenbrand <david@redhat.com>
|
|
*
|
|
* This header is BSD licensed so anyone can use the definitions
|
|
* to implement compatible drivers/servers:
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of IBM nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL IBM OR
|
|
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
|
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
|
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
|
|
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
|
|
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
|
|
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
|
|
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#ifndef _LINUX_VIRTIO_MEM_H
|
|
#define _LINUX_VIRTIO_MEM_H
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/virtio_types.h>
|
|
#include <linux/virtio_ids.h>
|
|
#include <linux/virtio_config.h>
|
|
|
|
/*
|
|
* Each virtio-mem device manages a dedicated region in physical address
|
|
* space. Each device can belong to a single NUMA node, multiple devices
|
|
* for a single NUMA node are possible. A virtio-mem device is like a
|
|
* "resizable DIMM" consisting of small memory blocks that can be plugged
|
|
* or unplugged. The device driver is responsible for (un)plugging memory
|
|
* blocks on demand.
|
|
*
|
|
* Virtio-mem devices can only operate on their assigned memory region in
|
|
* order to (un)plug memory. A device cannot (un)plug memory belonging to
|
|
* other devices.
|
|
*
|
|
* The "region_size" corresponds to the maximum amount of memory that can
|
|
* be provided by a device. The "size" corresponds to the amount of memory
|
|
* that is currently plugged. "requested_size" corresponds to a request
|
|
* from the device to the device driver to (un)plug blocks. The
|
|
* device driver should try to (un)plug blocks in order to reach the
|
|
* "requested_size". It is impossible to plug more memory than requested.
|
|
*
|
|
* The "usable_region_size" represents the memory region that can actually
|
|
* be used to (un)plug memory. It is always at least as big as the
|
|
* "requested_size" and will grow dynamically. It will only shrink when
|
|
* explicitly triggered (VIRTIO_MEM_REQ_UNPLUG).
|
|
*
|
|
* There are no guarantees what will happen if unplugged memory is
|
|
* read/written. Such memory should, in general, not be touched. E.g.,
|
|
* even writing might succeed, but the values will simply be discarded at
|
|
* random points in time.
|
|
*
|
|
* It can happen that the device cannot process a request, because it is
|
|
* busy. The device driver has to retry later.
|
|
*
|
|
* Usually, during system resets all memory will get unplugged, so the
|
|
* device driver can start with a clean state. However, in specific
|
|
* scenarios (if the device is busy) it can happen that the device still
|
|
* has memory plugged. The device driver can request to unplug all memory
|
|
* (VIRTIO_MEM_REQ_UNPLUG) - which might take a while to succeed if the
|
|
* device is busy.
|
|
*/
|
|
|
|
/* --- virtio-mem: feature bits --- */
|
|
|
|
/* node_id is an ACPI PXM and is valid */
|
|
#define VIRTIO_MEM_F_ACPI_PXM 0
|
|
|
|
|
|
/* --- virtio-mem: guest -> host requests --- */
|
|
|
|
/* request to plug memory blocks */
|
|
#define VIRTIO_MEM_REQ_PLUG 0
|
|
/* request to unplug memory blocks */
|
|
#define VIRTIO_MEM_REQ_UNPLUG 1
|
|
/* request to unplug all blocks and shrink the usable size */
|
|
#define VIRTIO_MEM_REQ_UNPLUG_ALL 2
|
|
/* request information about the plugged state of memory blocks */
|
|
#define VIRTIO_MEM_REQ_STATE 3
|
|
|
|
struct virtio_mem_req_plug {
|
|
__virtio64 addr;
|
|
__virtio16 nb_blocks;
|
|
__virtio16 padding[3];
|
|
};
|
|
|
|
struct virtio_mem_req_unplug {
|
|
__virtio64 addr;
|
|
__virtio16 nb_blocks;
|
|
__virtio16 padding[3];
|
|
};
|
|
|
|
struct virtio_mem_req_state {
|
|
__virtio64 addr;
|
|
__virtio16 nb_blocks;
|
|
__virtio16 padding[3];
|
|
};
|
|
|
|
struct virtio_mem_req {
|
|
__virtio16 type;
|
|
__virtio16 padding[3];
|
|
|
|
union {
|
|
struct virtio_mem_req_plug plug;
|
|
struct virtio_mem_req_unplug unplug;
|
|
struct virtio_mem_req_state state;
|
|
} u;
|
|
};
|
|
|
|
|
|
/* --- virtio-mem: host -> guest response --- */
|
|
|
|
/*
|
|
* Request processed successfully, applicable for
|
|
* - VIRTIO_MEM_REQ_PLUG
|
|
* - VIRTIO_MEM_REQ_UNPLUG
|
|
* - VIRTIO_MEM_REQ_UNPLUG_ALL
|
|
* - VIRTIO_MEM_REQ_STATE
|
|
*/
|
|
#define VIRTIO_MEM_RESP_ACK 0
|
|
/*
|
|
* Request denied - e.g. trying to plug more than requested, applicable for
|
|
* - VIRTIO_MEM_REQ_PLUG
|
|
*/
|
|
#define VIRTIO_MEM_RESP_NACK 1
|
|
/*
|
|
* Request cannot be processed right now, try again later, applicable for
|
|
* - VIRTIO_MEM_REQ_PLUG
|
|
* - VIRTIO_MEM_REQ_UNPLUG
|
|
* - VIRTIO_MEM_REQ_UNPLUG_ALL
|
|
*/
|
|
#define VIRTIO_MEM_RESP_BUSY 2
|
|
/*
|
|
* Error in request (e.g. addresses/alignment), applicable for
|
|
* - VIRTIO_MEM_REQ_PLUG
|
|
* - VIRTIO_MEM_REQ_UNPLUG
|
|
* - VIRTIO_MEM_REQ_STATE
|
|
*/
|
|
#define VIRTIO_MEM_RESP_ERROR 3
|
|
|
|
|
|
/* State of memory blocks is "plugged" */
|
|
#define VIRTIO_MEM_STATE_PLUGGED 0
|
|
/* State of memory blocks is "unplugged" */
|
|
#define VIRTIO_MEM_STATE_UNPLUGGED 1
|
|
/* State of memory blocks is "mixed" */
|
|
#define VIRTIO_MEM_STATE_MIXED 2
|
|
|
|
struct virtio_mem_resp_state {
|
|
__virtio16 state;
|
|
};
|
|
|
|
struct virtio_mem_resp {
|
|
__virtio16 type;
|
|
__virtio16 padding[3];
|
|
|
|
union {
|
|
struct virtio_mem_resp_state state;
|
|
} u;
|
|
};
|
|
|
|
/* --- virtio-mem: configuration --- */
|
|
|
|
struct virtio_mem_config {
|
|
/* Block size and alignment. Cannot change. */
|
|
__u64 block_size;
|
|
/* Valid with VIRTIO_MEM_F_ACPI_PXM. Cannot change. */
|
|
__u16 node_id;
|
|
__u8 padding[6];
|
|
/* Start address of the memory region. Cannot change. */
|
|
__u64 addr;
|
|
/* Region size (maximum). Cannot change. */
|
|
__u64 region_size;
|
|
/*
|
|
* Currently usable region size. Can grow up to region_size. Can
|
|
* shrink due to VIRTIO_MEM_REQ_UNPLUG_ALL (in which case no config
|
|
* update will be sent).
|
|
*/
|
|
__u64 usable_region_size;
|
|
/*
|
|
* Currently used size. Changes due to plug/unplug requests, but no
|
|
* config updates will be sent.
|
|
*/
|
|
__u64 plugged_size;
|
|
/* Requested size. New plug requests cannot exceed it. Can change. */
|
|
__u64 requested_size;
|
|
};
|
|
|
|
#endif /* _LINUX_VIRTIO_MEM_H */
|