f69bcbf3b4
This patch introduces the host "Virtio over PCIe" interface for Intel MIC. It allows creating user space backends on the host and instantiating virtio devices for them on the Intel MIC card. It uses the existing VRINGH infrastructure in the kernel to access virtio rings from the host. A character device per MIC is exposed with IOCTL, mmap and poll callbacks. This allows the user space backend to: (a) add/remove a virtio device via a device page. (b) map (R/O) virtio rings and device page to user space. (c) poll for availability of data. (d) copy a descriptor or entire descriptor chain to/from the card. (e) modify virtio configuration. (f) handle virtio device reset. The buffers are copied over using CPU copies for this initial patch and host initiated MIC DMA support is planned for future patches. The avail and desc virtio rings are in host memory and the used ring is in card memory to maximize writes across PCIe for performance. Co-author: Sudeep Dutt <sudeep.dutt@intel.com> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Signed-off-by: Caz Yokoyama <Caz.Yokoyama@intel.com> Signed-off-by: Dasaratharaman Chandramouli <dasaratharaman.chandramouli@intel.com> Signed-off-by: Nikhil Rao <nikhil.rao@intel.com> Signed-off-by: Harshavardhan R Kharche <harshavardhan.r.kharche@intel.com> Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com> Acked-by: Yaozu (Eddie) Dong <eddie.dong@intel.com> Reviewed-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
138 lines
4.4 KiB
C
138 lines
4.4 KiB
C
/*
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* Intel MIC Platform Software Stack (MPSS)
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*
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* Copyright(c) 2013 Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* The full GNU General Public License is included in this distribution in
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* the file called "COPYING".
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*
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* Intel MIC Host driver.
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*
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*/
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#ifndef MIC_VIRTIO_H
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#define MIC_VIRTIO_H
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#include <linux/virtio_config.h>
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#include <linux/mic_ioctl.h>
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/*
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* Note on endianness.
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* 1. Host can be both BE or LE
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* 2. Guest/card is LE. Host uses le_to_cpu to access desc/avail
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* rings and ioreadXX/iowriteXX to access used ring.
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* 3. Device page exposed by host to guest contains LE values. Guest
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* accesses these using ioreadXX/iowriteXX etc. This way in general we
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* obey the virtio spec according to which guest works with native
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* endianness and host is aware of guest endianness and does all
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* required endianness conversion.
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* 4. Data provided from user space to guest (in ADD_DEVICE and
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* CONFIG_CHANGE ioctl's) is not interpreted by the driver and should be
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* in guest endianness.
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*/
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/**
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* struct mic_vringh - Virtio ring host information.
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*
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* @vring: The MIC vring used for setting up user space mappings.
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* @vrh: The host VRINGH used for accessing the card vrings.
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* @riov: The VRINGH read kernel IOV.
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* @wiov: The VRINGH write kernel IOV.
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* @head: The VRINGH head index address passed to vringh_getdesc_kern(..).
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* @vr_mutex: Mutex for synchronizing access to the VRING.
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* @mvdev: Back pointer to MIC virtio device for vringh_notify(..).
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*/
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struct mic_vringh {
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struct mic_vring vring;
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struct vringh vrh;
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struct vringh_kiov riov;
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struct vringh_kiov wiov;
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u16 head;
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struct mutex vr_mutex;
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struct mic_vdev *mvdev;
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};
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/**
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* struct mic_vdev - Host information for a card Virtio device.
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*
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* @virtio_id - Virtio device id.
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* @waitq - Waitqueue to allow ring3 apps to poll.
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* @mdev - Back pointer to host MIC device.
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* @poll_wake - Used for waking up threads blocked in poll.
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* @out_bytes - Debug stats for number of bytes copied from host to card.
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* @in_bytes - Debug stats for number of bytes copied from card to host.
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* @mvr - Store per VRING data structures.
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* @virtio_bh_work - Work struct used to schedule virtio bottom half handling.
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* @dd - Virtio device descriptor.
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* @dc - Virtio device control fields.
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* @list - List of Virtio devices.
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* @virtio_db - The doorbell used by the card to interrupt the host.
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* @virtio_cookie - The cookie returned while requesting interrupts.
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*/
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struct mic_vdev {
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int virtio_id;
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wait_queue_head_t waitq;
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struct mic_device *mdev;
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int poll_wake;
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unsigned long out_bytes;
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unsigned long in_bytes;
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struct mic_vringh mvr[MIC_MAX_VRINGS];
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struct work_struct virtio_bh_work;
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struct mic_device_desc *dd;
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struct mic_device_ctrl *dc;
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struct list_head list;
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int virtio_db;
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struct mic_irq *virtio_cookie;
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};
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void mic_virtio_uninit(struct mic_device *mdev);
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int mic_virtio_add_device(struct mic_vdev *mvdev,
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void __user *argp);
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void mic_virtio_del_device(struct mic_vdev *mvdev);
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int mic_virtio_config_change(struct mic_vdev *mvdev,
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void __user *argp);
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int mic_virtio_copy_desc(struct mic_vdev *mvdev,
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struct mic_copy_desc *request);
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void mic_virtio_reset_devices(struct mic_device *mdev);
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void mic_bh_handler(struct work_struct *work);
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/* Helper API to obtain the MIC PCIe device */
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static inline struct device *mic_dev(struct mic_vdev *mvdev)
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{
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return mvdev->mdev->sdev->parent;
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}
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/* Helper API to check if a virtio device is initialized */
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static inline int mic_vdev_inited(struct mic_vdev *mvdev)
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{
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/* Device has not been created yet */
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if (!mvdev->dd || !mvdev->dd->type) {
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dev_err(mic_dev(mvdev), "%s %d err %d\n",
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__func__, __LINE__, -EINVAL);
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return -EINVAL;
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}
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/* Device has been removed/deleted */
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if (mvdev->dd->type == -1) {
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dev_err(mic_dev(mvdev), "%s %d err %d\n",
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__func__, __LINE__, -ENODEV);
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return -ENODEV;
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}
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return 0;
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}
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/* Helper API to check if a virtio device is running */
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static inline bool mic_vdevup(struct mic_vdev *mvdev)
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{
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return !!mvdev->dd->status;
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}
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#endif
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