include/uapi/linux/virtio_mem.h - linux/kernel/git/davem/net - Git at Google

 /* 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. */
 	__le64 block_size;
 	/* Valid with VIRTIO_MEM_F_ACPI_PXM. Cannot change. */
 	__le16 node_id;
 	__u8 padding[6];
 	/* Start address of the memory region. Cannot change. */
 	__le64 addr;
 	/* Region size (maximum). Cannot change. */
 	__le64 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).
 	 */
 	__le64 usable_region_size;
 	/*
 	 * Currently used size. Changes due to plug/unplug requests, but no
 	 * config updates will be sent.
 	 */
 	__le64 plugged_size;
 	/* Requested size. New plug requests cannot exceed it. Can change. */
 	__le64 requested_size;
 };

 #endif /* _LINUX_VIRTIO_MEM_H */
	/* 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. */
	__le64 block_size;
	/* Valid with VIRTIO_MEM_F_ACPI_PXM. Cannot change. */
	__le16 node_id;
	__u8 padding[6];
	/* Start address of the memory region. Cannot change. */
	__le64 addr;
	/* Region size (maximum). Cannot change. */
	__le64 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).
	*/
	__le64 usable_region_size;
	/*
	* Currently used size. Changes due to plug/unplug requests, but no
	* config updates will be sent.
	*/
	__le64 plugged_size;
	/* Requested size. New plug requests cannot exceed it. Can change. */
	__le64 requested_size;
	};

	#endif /* _LINUX_VIRTIO_MEM_H */