diff options
| -rw-r--r-- | Documentation/vfio.txt | 63 | ||||
| -rw-r--r-- | drivers/vfio/Kconfig | 6 | ||||
| -rw-r--r-- | drivers/vfio/Makefile | 1 | ||||
| -rw-r--r-- | drivers/vfio/vfio.c | 1 | ||||
| -rw-r--r-- | drivers/vfio/vfio_iommu_spapr_tce.c | 377 | ||||
| -rw-r--r-- | include/uapi/linux/vfio.h | 34 |
6 files changed, 482 insertions, 0 deletions
diff --git a/Documentation/vfio.txt b/Documentation/vfio.txt index 8eda3635a17d..c55533c0adb3 100644 --- a/Documentation/vfio.txt +++ b/Documentation/vfio.txt @@ -283,6 +283,69 @@ a direct pass through for VFIO_DEVICE_* ioctls. The read/write/mmap interfaces implement the device region access defined by the device's own VFIO_DEVICE_GET_REGION_INFO ioctl. + +PPC64 sPAPR implementation note +------------------------------------------------------------------------------- + +This implementation has some specifics: + +1) Only one IOMMU group per container is supported as an IOMMU group +represents the minimal entity which isolation can be guaranteed for and +groups are allocated statically, one per a Partitionable Endpoint (PE) +(PE is often a PCI domain but not always). + +2) The hardware supports so called DMA windows - the PCI address range +within which DMA transfer is allowed, any attempt to access address space +out of the window leads to the whole PE isolation. + +3) PPC64 guests are paravirtualized but not fully emulated. There is an API +to map/unmap pages for DMA, and it normally maps 1..32 pages per call and +currently there is no way to reduce the number of calls. In order to make things +faster, the map/unmap handling has been implemented in real mode which provides +an excellent performance which has limitations such as inability to do +locked pages accounting in real time. + +So 3 additional ioctls have been added: + + VFIO_IOMMU_SPAPR_TCE_GET_INFO - returns the size and the start + of the DMA window on the PCI bus. + + VFIO_IOMMU_ENABLE - enables the container. The locked pages accounting + is done at this point. This lets user first to know what + the DMA window is and adjust rlimit before doing any real job. + + VFIO_IOMMU_DISABLE - disables the container. + + +The code flow from the example above should be slightly changed: + + ..... + /* Add the group to the container */ + ioctl(group, VFIO_GROUP_SET_CONTAINER, &container); + + /* Enable the IOMMU model we want */ + ioctl(container, VFIO_SET_IOMMU, VFIO_SPAPR_TCE_IOMMU) + + /* Get addition sPAPR IOMMU info */ + vfio_iommu_spapr_tce_info spapr_iommu_info; + ioctl(container, VFIO_IOMMU_SPAPR_TCE_GET_INFO, &spapr_iommu_info); + + if (ioctl(container, VFIO_IOMMU_ENABLE)) + /* Cannot enable container, may be low rlimit */ + + /* Allocate some space and setup a DMA mapping */ + dma_map.vaddr = mmap(0, 1024 * 1024, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, 0, 0); + + dma_map.size = 1024 * 1024; + dma_map.iova = 0; /* 1MB starting at 0x0 from device view */ + dma_map.flags = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE; + + /* Check here is .iova/.size are within DMA window from spapr_iommu_info */ + + ioctl(container, VFIO_IOMMU_MAP_DMA, &dma_map); + ..... + ------------------------------------------------------------------------------- [1] VFIO was originally an acronym for "Virtual Function I/O" in its diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig index 7cd5dec0abd1..b464687f6e14 100644 --- a/drivers/vfio/Kconfig +++ b/drivers/vfio/Kconfig @@ -3,10 +3,16 @@ config VFIO_IOMMU_TYPE1 depends on VFIO default n +config VFIO_IOMMU_SPAPR_TCE + tristate + depends on VFIO && SPAPR_TCE_IOMMU + default n + menuconfig VFIO tristate "VFIO Non-Privileged userspace driver framework" depends on IOMMU_API select VFIO_IOMMU_TYPE1 if X86 + select VFIO_IOMMU_SPAPR_TCE if PPC_POWERNV help VFIO provides a framework for secure userspace device drivers. See Documentation/vfio.txt for more details. diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile index 2398d4a0e38b..72bfabc8629e 100644 --- a/drivers/vfio/Makefile +++ b/drivers/vfio/Makefile @@ -1,3 +1,4 @@ obj-$(CONFIG_VFIO) += vfio.o obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o +obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o obj-$(CONFIG_VFIO_PCI) += pci/ diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 6d78736563de..259ad282ae5d 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -1415,6 +1415,7 @@ static int __init vfio_init(void) * drivers. */ request_module_nowait("vfio_iommu_type1"); + request_module_nowait("vfio_iommu_spapr_tce"); return 0; diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c new file mode 100644 index 000000000000..bdae7a04af75 --- /dev/null +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -0,0 +1,377 @@ +/* + * 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(¤t->mm->mmap_sem); + npages = (tbl->it_size << IOMMU_PAGE_SHIFT) >> 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(¤t->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(¤t->mm->mmap_sem); + current->mm->locked_vm -= (container->tbl->it_size << + IOMMU_PAGE_SHIFT) >> PAGE_SHIFT; + up_write(¤t->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: + return (arg == VFIO_SPAPR_TCE_IOMMU) ? 1 : 0; + + 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; + info.dma32_window_size = tbl->it_size << IOMMU_PAGE_SHIFT; + 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(¶m, (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) || + (param.vaddr & ~IOMMU_PAGE_MASK)) + 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); ++i) { + ret = iommu_put_tce_user_mode(tbl, + (param.iova >> IOMMU_PAGE_SHIFT) + i, + tce); + if (ret) + break; + tce += IOMMU_PAGE_SIZE; + } + if (ret) + iommu_clear_tces_and_put_pages(tbl, + param.iova >> IOMMU_PAGE_SHIFT, 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(¶m, (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) + return -EINVAL; + + ret = iommu_tce_clear_param_check(tbl, param.iova, 0, + param.size >> IOMMU_PAGE_SHIFT); + if (ret) + return ret; + + ret = iommu_clear_tces_and_put_pages(tbl, + param.iova >> IOMMU_PAGE_SHIFT, + param.size >> IOMMU_PAGE_SHIFT); + 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; + } + + 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); + diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 284ff2436829..87ee4f4cff25 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -22,6 +22,7 @@ /* Extensions */ #define VFIO_TYPE1_IOMMU 1 +#define VFIO_SPAPR_TCE_IOMMU 2 /* * The IOCTL interface is designed for extensibility by embedding the @@ -375,4 +376,37 @@ struct vfio_iommu_type1_dma_unmap { #define VFIO_IOMMU_UNMAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 14) +/* + * IOCTLs to enable/disable IOMMU container usage. + * No parameters are supported. + */ +#define VFIO_IOMMU_ENABLE _IO(VFIO_TYPE, VFIO_BASE + 15) +#define VFIO_IOMMU_DISABLE _IO(VFIO_TYPE, VFIO_BASE + 16) + +/* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */ + +/* + * The SPAPR TCE info struct provides the information about the PCI bus + * address ranges available for DMA, these values are programmed into + * the hardware so the guest has to know that information. + * + * The DMA 32 bit window start is an absolute PCI bus address. + * The IOVA address passed via map/unmap ioctls are absolute PCI bus + * addresses too so the window works as a filter rather than an offset + * for IOVA addresses. + * + * A flag will need to be added if other page sizes are supported, + * so as defined here, it is always 4k. + */ +struct vfio_iommu_spapr_tce_info { + __u32 argsz; + __u32 flags; /* reserved for future use */ + __u32 dma32_window_start; /* 32 bit window start (bytes) */ + __u32 dma32_window_size; /* 32 bit window size (bytes) */ +}; + +#define VFIO_IOMMU_SPAPR_TCE_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12) + +/* ***************************************************************** */ + #endif /* _UAPIVFIO_H */ |