linux/drivers/dma/idxd/cdev.c
Dave Jiang 8e50d39265 dmaengine: idxd: Add shared workqueue support
Add shared workqueue support that includes the support of Shared Virtual
memory (SVM) or in similar terms On Demand Paging (ODP). The shared
workqueue uses the enqcmds command in kernel and will respond with retry if
the workqueue is full. Shared workqueue only works when there is PASID
support from the IOMMU.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/160382007499.3911367.26043087963708134.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2020-10-30 14:10:36 +05:30

366 lines
8.1 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2019 Intel Corporation. All rights rsvd. */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/device.h>
#include <linux/sched/task.h>
#include <linux/intel-svm.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/iommu.h>
#include <uapi/linux/idxd.h>
#include "registers.h"
#include "idxd.h"
struct idxd_cdev_context {
const char *name;
dev_t devt;
struct ida minor_ida;
};
/*
* ictx is an array based off of accelerator types. enum idxd_type
* is used as index
*/
static struct idxd_cdev_context ictx[IDXD_TYPE_MAX] = {
{ .name = "dsa" },
};
struct idxd_user_context {
struct idxd_wq *wq;
struct task_struct *task;
unsigned int pasid;
unsigned int flags;
struct iommu_sva *sva;
};
enum idxd_cdev_cleanup {
CDEV_NORMAL = 0,
CDEV_FAILED,
};
static void idxd_cdev_dev_release(struct device *dev)
{
dev_dbg(dev, "releasing cdev device\n");
kfree(dev);
}
static struct device_type idxd_cdev_device_type = {
.name = "idxd_cdev",
.release = idxd_cdev_dev_release,
};
static inline struct idxd_cdev *inode_idxd_cdev(struct inode *inode)
{
struct cdev *cdev = inode->i_cdev;
return container_of(cdev, struct idxd_cdev, cdev);
}
static inline struct idxd_wq *idxd_cdev_wq(struct idxd_cdev *idxd_cdev)
{
return container_of(idxd_cdev, struct idxd_wq, idxd_cdev);
}
static inline struct idxd_wq *inode_wq(struct inode *inode)
{
return idxd_cdev_wq(inode_idxd_cdev(inode));
}
static int idxd_cdev_open(struct inode *inode, struct file *filp)
{
struct idxd_user_context *ctx;
struct idxd_device *idxd;
struct idxd_wq *wq;
struct device *dev;
int rc = 0;
struct iommu_sva *sva;
unsigned int pasid;
wq = inode_wq(inode);
idxd = wq->idxd;
dev = &idxd->pdev->dev;
dev_dbg(dev, "%s called: %d\n", __func__, idxd_wq_refcount(wq));
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
mutex_lock(&wq->wq_lock);
if (idxd_wq_refcount(wq) > 0 && wq_dedicated(wq)) {
rc = -EBUSY;
goto failed;
}
ctx->wq = wq;
filp->private_data = ctx;
if (device_pasid_enabled(idxd)) {
sva = iommu_sva_bind_device(dev, current->mm, NULL);
if (IS_ERR(sva)) {
rc = PTR_ERR(sva);
dev_err(dev, "pasid allocation failed: %d\n", rc);
goto failed;
}
pasid = iommu_sva_get_pasid(sva);
if (pasid == IOMMU_PASID_INVALID) {
iommu_sva_unbind_device(sva);
goto failed;
}
ctx->sva = sva;
ctx->pasid = pasid;
if (wq_dedicated(wq)) {
rc = idxd_wq_set_pasid(wq, pasid);
if (rc < 0) {
iommu_sva_unbind_device(sva);
dev_err(dev, "wq set pasid failed: %d\n", rc);
goto failed;
}
}
}
idxd_wq_get(wq);
mutex_unlock(&wq->wq_lock);
return 0;
failed:
mutex_unlock(&wq->wq_lock);
kfree(ctx);
return rc;
}
static int idxd_cdev_release(struct inode *node, struct file *filep)
{
struct idxd_user_context *ctx = filep->private_data;
struct idxd_wq *wq = ctx->wq;
struct idxd_device *idxd = wq->idxd;
struct device *dev = &idxd->pdev->dev;
int rc;
dev_dbg(dev, "%s called\n", __func__);
filep->private_data = NULL;
/* Wait for in-flight operations to complete. */
if (wq_shared(wq)) {
idxd_device_drain_pasid(idxd, ctx->pasid);
} else {
if (device_pasid_enabled(idxd)) {
/* The wq disable in the disable pasid function will drain the wq */
rc = idxd_wq_disable_pasid(wq);
if (rc < 0)
dev_err(dev, "wq disable pasid failed.\n");
} else {
idxd_wq_drain(wq);
}
}
if (ctx->sva)
iommu_sva_unbind_device(ctx->sva);
kfree(ctx);
mutex_lock(&wq->wq_lock);
idxd_wq_put(wq);
mutex_unlock(&wq->wq_lock);
return 0;
}
static int check_vma(struct idxd_wq *wq, struct vm_area_struct *vma,
const char *func)
{
struct device *dev = &wq->idxd->pdev->dev;
if ((vma->vm_end - vma->vm_start) > PAGE_SIZE) {
dev_info_ratelimited(dev,
"%s: %s: mapping too large: %lu\n",
current->comm, func,
vma->vm_end - vma->vm_start);
return -EINVAL;
}
return 0;
}
static int idxd_cdev_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct idxd_user_context *ctx = filp->private_data;
struct idxd_wq *wq = ctx->wq;
struct idxd_device *idxd = wq->idxd;
struct pci_dev *pdev = idxd->pdev;
phys_addr_t base = pci_resource_start(pdev, IDXD_WQ_BAR);
unsigned long pfn;
int rc;
dev_dbg(&pdev->dev, "%s called\n", __func__);
rc = check_vma(wq, vma, __func__);
if (rc < 0)
return rc;
vma->vm_flags |= VM_DONTCOPY;
pfn = (base + idxd_get_wq_portal_full_offset(wq->id,
IDXD_PORTAL_LIMITED)) >> PAGE_SHIFT;
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
vma->vm_private_data = ctx;
return io_remap_pfn_range(vma, vma->vm_start, pfn, PAGE_SIZE,
vma->vm_page_prot);
}
static __poll_t idxd_cdev_poll(struct file *filp,
struct poll_table_struct *wait)
{
struct idxd_user_context *ctx = filp->private_data;
struct idxd_wq *wq = ctx->wq;
struct idxd_device *idxd = wq->idxd;
struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
unsigned long flags;
__poll_t out = 0;
poll_wait(filp, &idxd_cdev->err_queue, wait);
spin_lock_irqsave(&idxd->dev_lock, flags);
if (idxd->sw_err.valid)
out = EPOLLIN | EPOLLRDNORM;
spin_unlock_irqrestore(&idxd->dev_lock, flags);
return out;
}
static const struct file_operations idxd_cdev_fops = {
.owner = THIS_MODULE,
.open = idxd_cdev_open,
.release = idxd_cdev_release,
.mmap = idxd_cdev_mmap,
.poll = idxd_cdev_poll,
};
int idxd_cdev_get_major(struct idxd_device *idxd)
{
return MAJOR(ictx[idxd->type].devt);
}
static int idxd_wq_cdev_dev_setup(struct idxd_wq *wq)
{
struct idxd_device *idxd = wq->idxd;
struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
struct idxd_cdev_context *cdev_ctx;
struct device *dev;
int minor, rc;
idxd_cdev->dev = kzalloc(sizeof(*idxd_cdev->dev), GFP_KERNEL);
if (!idxd_cdev->dev)
return -ENOMEM;
dev = idxd_cdev->dev;
dev->parent = &idxd->pdev->dev;
dev_set_name(dev, "%s/wq%u.%u", idxd_get_dev_name(idxd),
idxd->id, wq->id);
dev->bus = idxd_get_bus_type(idxd);
cdev_ctx = &ictx[wq->idxd->type];
minor = ida_simple_get(&cdev_ctx->minor_ida, 0, MINORMASK, GFP_KERNEL);
if (minor < 0) {
rc = minor;
kfree(dev);
goto ida_err;
}
dev->devt = MKDEV(MAJOR(cdev_ctx->devt), minor);
dev->type = &idxd_cdev_device_type;
rc = device_register(dev);
if (rc < 0) {
dev_err(&idxd->pdev->dev, "device register failed\n");
goto dev_reg_err;
}
idxd_cdev->minor = minor;
return 0;
dev_reg_err:
ida_simple_remove(&cdev_ctx->minor_ida, MINOR(dev->devt));
put_device(dev);
ida_err:
idxd_cdev->dev = NULL;
return rc;
}
static void idxd_wq_cdev_cleanup(struct idxd_wq *wq,
enum idxd_cdev_cleanup cdev_state)
{
struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
struct idxd_cdev_context *cdev_ctx;
cdev_ctx = &ictx[wq->idxd->type];
if (cdev_state == CDEV_NORMAL)
cdev_del(&idxd_cdev->cdev);
device_unregister(idxd_cdev->dev);
/*
* The device_type->release() will be called on the device and free
* the allocated struct device. We can just forget it.
*/
ida_simple_remove(&cdev_ctx->minor_ida, idxd_cdev->minor);
idxd_cdev->dev = NULL;
idxd_cdev->minor = -1;
}
int idxd_wq_add_cdev(struct idxd_wq *wq)
{
struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
struct cdev *cdev = &idxd_cdev->cdev;
struct device *dev;
int rc;
rc = idxd_wq_cdev_dev_setup(wq);
if (rc < 0)
return rc;
dev = idxd_cdev->dev;
cdev_init(cdev, &idxd_cdev_fops);
cdev_set_parent(cdev, &dev->kobj);
rc = cdev_add(cdev, dev->devt, 1);
if (rc) {
dev_dbg(&wq->idxd->pdev->dev, "cdev_add failed: %d\n", rc);
idxd_wq_cdev_cleanup(wq, CDEV_FAILED);
return rc;
}
init_waitqueue_head(&idxd_cdev->err_queue);
return 0;
}
void idxd_wq_del_cdev(struct idxd_wq *wq)
{
idxd_wq_cdev_cleanup(wq, CDEV_NORMAL);
}
int idxd_cdev_register(void)
{
int rc, i;
for (i = 0; i < IDXD_TYPE_MAX; i++) {
ida_init(&ictx[i].minor_ida);
rc = alloc_chrdev_region(&ictx[i].devt, 0, MINORMASK,
ictx[i].name);
if (rc)
return rc;
}
return 0;
}
void idxd_cdev_remove(void)
{
int i;
for (i = 0; i < IDXD_TYPE_MAX; i++) {
unregister_chrdev_region(ictx[i].devt, MINORMASK);
ida_destroy(&ictx[i].minor_ida);
}
}