linux/drivers/vfio/vfio_iommu_spapr_tce.c
Gavin Shan 1b69be5e8a drivers/vfio: EEH support for VFIO PCI device
The patch adds new IOCTL commands for sPAPR VFIO container device
to support EEH functionality for PCI devices, which have been passed
through from host to somebody else via VFIO.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Alexander Graf <agraf@suse.de>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-05 15:28:48 +10:00

392 lines
9.8 KiB
C

/*
* VFIO: IOMMU DMA mapping support for TCE on POWER
*
* Copyright (C) 2013 IBM Corp. All rights reserved.
* Author: Alexey Kardashevskiy <aik@ozlabs.ru>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Derived from original vfio_iommu_type1.c:
* Copyright (C) 2012 Red Hat, Inc. All rights reserved.
* Author: Alex Williamson <alex.williamson@redhat.com>
*/
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/err.h>
#include <linux/vfio.h>
#include <asm/iommu.h>
#include <asm/tce.h>
#define DRIVER_VERSION "0.1"
#define DRIVER_AUTHOR "aik@ozlabs.ru"
#define DRIVER_DESC "VFIO IOMMU SPAPR TCE"
static void tce_iommu_detach_group(void *iommu_data,
struct iommu_group *iommu_group);
/*
* VFIO IOMMU fd for SPAPR_TCE IOMMU implementation
*
* This code handles mapping and unmapping of user data buffers
* into DMA'ble space using the IOMMU
*/
/*
* The container descriptor supports only a single group per container.
* Required by the API as the container is not supplied with the IOMMU group
* at the moment of initialization.
*/
struct tce_container {
struct mutex lock;
struct iommu_table *tbl;
bool enabled;
};
static int tce_iommu_enable(struct tce_container *container)
{
int ret = 0;
unsigned long locked, lock_limit, npages;
struct iommu_table *tbl = container->tbl;
if (!container->tbl)
return -ENXIO;
if (!current->mm)
return -ESRCH; /* process exited */
if (container->enabled)
return -EBUSY;
/*
* When userspace pages are mapped into the IOMMU, they are effectively
* locked memory, so, theoretically, we need to update the accounting
* of locked pages on each map and unmap. For powerpc, the map unmap
* paths can be very hot, though, and the accounting would kill
* performance, especially since it would be difficult to impossible
* to handle the accounting in real mode only.
*
* To address that, rather than precisely accounting every page, we
* instead account for a worst case on locked memory when the iommu is
* enabled and disabled. The worst case upper bound on locked memory
* is the size of the whole iommu window, which is usually relatively
* small (compared to total memory sizes) on POWER hardware.
*
* Also we don't have a nice way to fail on H_PUT_TCE due to ulimits,
* that would effectively kill the guest at random points, much better
* enforcing the limit based on the max that the guest can map.
*/
down_write(&current->mm->mmap_sem);
npages = (tbl->it_size << IOMMU_PAGE_SHIFT_4K) >> PAGE_SHIFT;
locked = current->mm->locked_vm + npages;
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if (locked > lock_limit && !capable(CAP_IPC_LOCK)) {
pr_warn("RLIMIT_MEMLOCK (%ld) exceeded\n",
rlimit(RLIMIT_MEMLOCK));
ret = -ENOMEM;
} else {
current->mm->locked_vm += npages;
container->enabled = true;
}
up_write(&current->mm->mmap_sem);
return ret;
}
static void tce_iommu_disable(struct tce_container *container)
{
if (!container->enabled)
return;
container->enabled = false;
if (!container->tbl || !current->mm)
return;
down_write(&current->mm->mmap_sem);
current->mm->locked_vm -= (container->tbl->it_size <<
IOMMU_PAGE_SHIFT_4K) >> PAGE_SHIFT;
up_write(&current->mm->mmap_sem);
}
static void *tce_iommu_open(unsigned long arg)
{
struct tce_container *container;
if (arg != VFIO_SPAPR_TCE_IOMMU) {
pr_err("tce_vfio: Wrong IOMMU type\n");
return ERR_PTR(-EINVAL);
}
container = kzalloc(sizeof(*container), GFP_KERNEL);
if (!container)
return ERR_PTR(-ENOMEM);
mutex_init(&container->lock);
return container;
}
static void tce_iommu_release(void *iommu_data)
{
struct tce_container *container = iommu_data;
WARN_ON(container->tbl && !container->tbl->it_group);
tce_iommu_disable(container);
if (container->tbl && container->tbl->it_group)
tce_iommu_detach_group(iommu_data, container->tbl->it_group);
mutex_destroy(&container->lock);
kfree(container);
}
static long tce_iommu_ioctl(void *iommu_data,
unsigned int cmd, unsigned long arg)
{
struct tce_container *container = iommu_data;
unsigned long minsz;
long ret;
switch (cmd) {
case VFIO_CHECK_EXTENSION:
switch (arg) {
case VFIO_SPAPR_TCE_IOMMU:
ret = 1;
break;
default:
ret = vfio_spapr_iommu_eeh_ioctl(NULL, cmd, arg);
break;
}
return (ret < 0) ? 0 : ret;
case VFIO_IOMMU_SPAPR_TCE_GET_INFO: {
struct vfio_iommu_spapr_tce_info info;
struct iommu_table *tbl = container->tbl;
if (WARN_ON(!tbl))
return -ENXIO;
minsz = offsetofend(struct vfio_iommu_spapr_tce_info,
dma32_window_size);
if (copy_from_user(&info, (void __user *)arg, minsz))
return -EFAULT;
if (info.argsz < minsz)
return -EINVAL;
info.dma32_window_start = tbl->it_offset << IOMMU_PAGE_SHIFT_4K;
info.dma32_window_size = tbl->it_size << IOMMU_PAGE_SHIFT_4K;
info.flags = 0;
if (copy_to_user((void __user *)arg, &info, minsz))
return -EFAULT;
return 0;
}
case VFIO_IOMMU_MAP_DMA: {
struct vfio_iommu_type1_dma_map param;
struct iommu_table *tbl = container->tbl;
unsigned long tce, i;
if (!tbl)
return -ENXIO;
BUG_ON(!tbl->it_group);
minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
if (copy_from_user(&param, (void __user *)arg, minsz))
return -EFAULT;
if (param.argsz < minsz)
return -EINVAL;
if (param.flags & ~(VFIO_DMA_MAP_FLAG_READ |
VFIO_DMA_MAP_FLAG_WRITE))
return -EINVAL;
if ((param.size & ~IOMMU_PAGE_MASK_4K) ||
(param.vaddr & ~IOMMU_PAGE_MASK_4K))
return -EINVAL;
/* iova is checked by the IOMMU API */
tce = param.vaddr;
if (param.flags & VFIO_DMA_MAP_FLAG_READ)
tce |= TCE_PCI_READ;
if (param.flags & VFIO_DMA_MAP_FLAG_WRITE)
tce |= TCE_PCI_WRITE;
ret = iommu_tce_put_param_check(tbl, param.iova, tce);
if (ret)
return ret;
for (i = 0; i < (param.size >> IOMMU_PAGE_SHIFT_4K); ++i) {
ret = iommu_put_tce_user_mode(tbl,
(param.iova >> IOMMU_PAGE_SHIFT_4K) + i,
tce);
if (ret)
break;
tce += IOMMU_PAGE_SIZE_4K;
}
if (ret)
iommu_clear_tces_and_put_pages(tbl,
param.iova >> IOMMU_PAGE_SHIFT_4K, i);
iommu_flush_tce(tbl);
return ret;
}
case VFIO_IOMMU_UNMAP_DMA: {
struct vfio_iommu_type1_dma_unmap param;
struct iommu_table *tbl = container->tbl;
if (WARN_ON(!tbl))
return -ENXIO;
minsz = offsetofend(struct vfio_iommu_type1_dma_unmap,
size);
if (copy_from_user(&param, (void __user *)arg, minsz))
return -EFAULT;
if (param.argsz < minsz)
return -EINVAL;
/* No flag is supported now */
if (param.flags)
return -EINVAL;
if (param.size & ~IOMMU_PAGE_MASK_4K)
return -EINVAL;
ret = iommu_tce_clear_param_check(tbl, param.iova, 0,
param.size >> IOMMU_PAGE_SHIFT_4K);
if (ret)
return ret;
ret = iommu_clear_tces_and_put_pages(tbl,
param.iova >> IOMMU_PAGE_SHIFT_4K,
param.size >> IOMMU_PAGE_SHIFT_4K);
iommu_flush_tce(tbl);
return ret;
}
case VFIO_IOMMU_ENABLE:
mutex_lock(&container->lock);
ret = tce_iommu_enable(container);
mutex_unlock(&container->lock);
return ret;
case VFIO_IOMMU_DISABLE:
mutex_lock(&container->lock);
tce_iommu_disable(container);
mutex_unlock(&container->lock);
return 0;
case VFIO_EEH_PE_OP:
if (!container->tbl || !container->tbl->it_group)
return -ENODEV;
return vfio_spapr_iommu_eeh_ioctl(container->tbl->it_group,
cmd, arg);
}
return -ENOTTY;
}
static int tce_iommu_attach_group(void *iommu_data,
struct iommu_group *iommu_group)
{
int ret;
struct tce_container *container = iommu_data;
struct iommu_table *tbl = iommu_group_get_iommudata(iommu_group);
BUG_ON(!tbl);
mutex_lock(&container->lock);
/* pr_debug("tce_vfio: Attaching group #%u to iommu %p\n",
iommu_group_id(iommu_group), iommu_group); */
if (container->tbl) {
pr_warn("tce_vfio: Only one group per IOMMU container is allowed, existing id=%d, attaching id=%d\n",
iommu_group_id(container->tbl->it_group),
iommu_group_id(iommu_group));
ret = -EBUSY;
} else if (container->enabled) {
pr_err("tce_vfio: attaching group #%u to enabled container\n",
iommu_group_id(iommu_group));
ret = -EBUSY;
} else {
ret = iommu_take_ownership(tbl);
if (!ret)
container->tbl = tbl;
}
mutex_unlock(&container->lock);
return ret;
}
static void tce_iommu_detach_group(void *iommu_data,
struct iommu_group *iommu_group)
{
struct tce_container *container = iommu_data;
struct iommu_table *tbl = iommu_group_get_iommudata(iommu_group);
BUG_ON(!tbl);
mutex_lock(&container->lock);
if (tbl != container->tbl) {
pr_warn("tce_vfio: detaching group #%u, expected group is #%u\n",
iommu_group_id(iommu_group),
iommu_group_id(tbl->it_group));
} else {
if (container->enabled) {
pr_warn("tce_vfio: detaching group #%u from enabled container, forcing disable\n",
iommu_group_id(tbl->it_group));
tce_iommu_disable(container);
}
/* pr_debug("tce_vfio: detaching group #%u from iommu %p\n",
iommu_group_id(iommu_group), iommu_group); */
container->tbl = NULL;
iommu_release_ownership(tbl);
}
mutex_unlock(&container->lock);
}
const struct vfio_iommu_driver_ops tce_iommu_driver_ops = {
.name = "iommu-vfio-powerpc",
.owner = THIS_MODULE,
.open = tce_iommu_open,
.release = tce_iommu_release,
.ioctl = tce_iommu_ioctl,
.attach_group = tce_iommu_attach_group,
.detach_group = tce_iommu_detach_group,
};
static int __init tce_iommu_init(void)
{
return vfio_register_iommu_driver(&tce_iommu_driver_ops);
}
static void __exit tce_iommu_cleanup(void)
{
vfio_unregister_iommu_driver(&tce_iommu_driver_ops);
}
module_init(tce_iommu_init);
module_exit(tce_iommu_cleanup);
MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);