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qemu/util/vfio-helpers.c

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/*
* VFIO utility
*
* Copyright 2016 - 2018 Red Hat, Inc.
*
* Authors:
* Fam Zheng <famz@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include <sys/ioctl.h>
#include <linux/vfio.h>
#include "qapi/error.h"
#include "exec/ramlist.h"
#include "exec/cpu-common.h"
#include "trace.h"
#include "qemu/queue.h"
#include "qemu/error-report.h"
#include "standard-headers/linux/pci_regs.h"
#include "qemu/event_notifier.h"
#include "qemu/vfio-helpers.h"
#include "trace.h"
#define QEMU_VFIO_DEBUG 0
#define QEMU_VFIO_IOVA_MIN 0x10000ULL
/* XXX: Once VFIO exposes the iova bit width in the IOMMU capability interface,
* we can use a runtime limit; alternatively it's also possible to do platform
* specific detection by reading sysfs entries. Until then, 39 is a safe bet.
**/
#define QEMU_VFIO_IOVA_MAX (1ULL << 39)
typedef struct {
/* Page aligned addr. */
void *host;
size_t size;
uint64_t iova;
} IOVAMapping;
struct QEMUVFIOState {
QemuMutex lock;
/* These fields are protected by BQL */
int container;
int group;
int device;
RAMBlockNotifier ram_notifier;
struct vfio_region_info config_region_info, bar_region_info[6];
/* These fields are protected by @lock */
/* VFIO's IO virtual address space is managed by splitting into a few
* sections:
*
* --------------- <= 0
* |xxxxxxxxxxxxx|
* |-------------| <= QEMU_VFIO_IOVA_MIN
* | |
* | Fixed |
* | |
* |-------------| <= low_water_mark
* | |
* | Free |
* | |
* |-------------| <= high_water_mark
* | |
* | Temp |
* | |
* |-------------| <= QEMU_VFIO_IOVA_MAX
* |xxxxxxxxxxxxx|
* |xxxxxxxxxxxxx|
* ---------------
*
* - Addresses lower than QEMU_VFIO_IOVA_MIN are reserved as invalid;
*
* - Fixed mappings of HVAs are assigned "low" IOVAs in the range of
* [QEMU_VFIO_IOVA_MIN, low_water_mark). Once allocated they will not be
* reclaimed - low_water_mark never shrinks;
*
* - IOVAs in range [low_water_mark, high_water_mark) are free;
*
* - IOVAs in range [high_water_mark, QEMU_VFIO_IOVA_MAX) are volatile
* mappings. At each qemu_vfio_dma_reset_temporary() call, the whole area
* is recycled. The caller should make sure I/O's depending on these
* mappings are completed before calling.
**/
uint64_t low_water_mark;
uint64_t high_water_mark;
IOVAMapping *mappings;
int nr_mappings;
};
/**
* Find group file by PCI device address as specified @device, and return the
* path. The returned string is owned by caller and should be g_free'ed later.
*/
static char *sysfs_find_group_file(const char *device, Error **errp)
{
char *sysfs_link;
char *sysfs_group;
char *p;
char *path = NULL;
sysfs_link = g_strdup_printf("/sys/bus/pci/devices/%s/iommu_group", device);
sysfs_group = g_malloc0(PATH_MAX);
if (readlink(sysfs_link, sysfs_group, PATH_MAX - 1) == -1) {
error_setg_errno(errp, errno, "Failed to find iommu group sysfs path");
goto out;
}
p = strrchr(sysfs_group, '/');
if (!p) {
error_setg(errp, "Failed to find iommu group number");
goto out;
}
path = g_strdup_printf("/dev/vfio/%s", p + 1);
out:
g_free(sysfs_link);
g_free(sysfs_group);
return path;
}
static inline void assert_bar_index_valid(QEMUVFIOState *s, int index)
{
assert(index >= 0 && index < ARRAY_SIZE(s->bar_region_info));
}
static int qemu_vfio_pci_init_bar(QEMUVFIOState *s, int index, Error **errp)
{
assert_bar_index_valid(s, index);
s->bar_region_info[index] = (struct vfio_region_info) {
.index = VFIO_PCI_BAR0_REGION_INDEX + index,
.argsz = sizeof(struct vfio_region_info),
};
if (ioctl(s->device, VFIO_DEVICE_GET_REGION_INFO, &s->bar_region_info[index])) {
error_setg_errno(errp, errno, "Failed to get BAR region info");
return -errno;
}
return 0;
}
/**
* Map a PCI bar area.
*/
void *qemu_vfio_pci_map_bar(QEMUVFIOState *s, int index,
uint64_t offset, uint64_t size,
Error **errp)
{
void *p;
assert_bar_index_valid(s, index);
p = mmap(NULL, MIN(size, s->bar_region_info[index].size - offset),
PROT_READ | PROT_WRITE, MAP_SHARED,
s->device, s->bar_region_info[index].offset + offset);
if (p == MAP_FAILED) {
error_setg_errno(errp, errno, "Failed to map BAR region");
p = NULL;
}
return p;
}
/**
* Unmap a PCI bar area.
*/
void qemu_vfio_pci_unmap_bar(QEMUVFIOState *s, int index, void *bar,
uint64_t offset, uint64_t size)
{
if (bar) {
munmap(bar, MIN(size, s->bar_region_info[index].size - offset));
}
}
/**
* Initialize device IRQ with @irq_type and and register an event notifier.
*/
int qemu_vfio_pci_init_irq(QEMUVFIOState *s, EventNotifier *e,
int irq_type, Error **errp)
{
int r;
struct vfio_irq_set *irq_set;
size_t irq_set_size;
struct vfio_irq_info irq_info = { .argsz = sizeof(irq_info) };
irq_info.index = irq_type;
if (ioctl(s->device, VFIO_DEVICE_GET_IRQ_INFO, &irq_info)) {
error_setg_errno(errp, errno, "Failed to get device interrupt info");
return -errno;
}
if (!(irq_info.flags & VFIO_IRQ_INFO_EVENTFD)) {
error_setg(errp, "Device interrupt doesn't support eventfd");
return -EINVAL;
}
irq_set_size = sizeof(*irq_set) + sizeof(int);
irq_set = g_malloc0(irq_set_size);
/* Get to a known IRQ state */
*irq_set = (struct vfio_irq_set) {
.argsz = irq_set_size,
.flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER,
.index = irq_info.index,
.start = 0,
.count = 1,
};
*(int *)&irq_set->data = event_notifier_get_fd(e);
r = ioctl(s->device, VFIO_DEVICE_SET_IRQS, irq_set);
g_free(irq_set);
if (r) {
error_setg_errno(errp, errno, "Failed to setup device interrupt");
return -errno;
}
return 0;
}
static int qemu_vfio_pci_read_config(QEMUVFIOState *s, void *buf,
int size, int ofs)
{
int ret;
do {
ret = pread(s->device, buf, size, s->config_region_info.offset + ofs);
} while (ret == -1 && errno == EINTR);
return ret == size ? 0 : -errno;
}
static int qemu_vfio_pci_write_config(QEMUVFIOState *s, void *buf, int size, int ofs)
{
int ret;
do {
ret = pwrite(s->device, buf, size, s->config_region_info.offset + ofs);
} while (ret == -1 && errno == EINTR);
return ret == size ? 0 : -errno;
}
static int qemu_vfio_init_pci(QEMUVFIOState *s, const char *device,
Error **errp)
{
int ret;
int i;
uint16_t pci_cmd;
struct vfio_group_status group_status = { .argsz = sizeof(group_status) };
struct vfio_iommu_type1_info iommu_info = { .argsz = sizeof(iommu_info) };
struct vfio_device_info device_info = { .argsz = sizeof(device_info) };
char *group_file = NULL;
/* Create a new container */
s->container = open("/dev/vfio/vfio", O_RDWR);
if (s->container == -1) {
error_setg_errno(errp, errno, "Failed to open /dev/vfio/vfio");
return -errno;
}
if (ioctl(s->container, VFIO_GET_API_VERSION) != VFIO_API_VERSION) {
error_setg(errp, "Invalid VFIO version");
ret = -EINVAL;
goto fail_container;
}
if (!ioctl(s->container, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU)) {
error_setg_errno(errp, errno, "VFIO IOMMU check failed");
ret = -EINVAL;
goto fail_container;
}
/* Open the group */
group_file = sysfs_find_group_file(device, errp);
if (!group_file) {
ret = -EINVAL;
goto fail_container;
}
s->group = open(group_file, O_RDWR);
if (s->group == -1) {
error_setg_errno(errp, errno, "Failed to open VFIO group file: %s",
group_file);
g_free(group_file);
ret = -errno;
goto fail_container;
}
g_free(group_file);
/* Test the group is viable and available */
if (ioctl(s->group, VFIO_GROUP_GET_STATUS, &group_status)) {
error_setg_errno(errp, errno, "Failed to get VFIO group status");
ret = -errno;
goto fail;
}
if (!(group_status.flags & VFIO_GROUP_FLAGS_VIABLE)) {
error_setg(errp, "VFIO group is not viable");
ret = -EINVAL;
goto fail;
}
/* Add the group to the container */
if (ioctl(s->group, VFIO_GROUP_SET_CONTAINER, &s->container)) {
error_setg_errno(errp, errno, "Failed to add group to VFIO container");
ret = -errno;
goto fail;
}
/* Enable the IOMMU model we want */
if (ioctl(s->container, VFIO_SET_IOMMU, VFIO_TYPE1_IOMMU)) {
error_setg_errno(errp, errno, "Failed to set VFIO IOMMU type");
ret = -errno;
goto fail;
}
/* Get additional IOMMU info */
if (ioctl(s->container, VFIO_IOMMU_GET_INFO, &iommu_info)) {
error_setg_errno(errp, errno, "Failed to get IOMMU info");
ret = -errno;
goto fail;
}
s->device = ioctl(s->group, VFIO_GROUP_GET_DEVICE_FD, device);
if (s->device < 0) {
error_setg_errno(errp, errno, "Failed to get device fd");
ret = -errno;
goto fail;
}
/* Test and setup the device */
if (ioctl(s->device, VFIO_DEVICE_GET_INFO, &device_info)) {
error_setg_errno(errp, errno, "Failed to get device info");
ret = -errno;
goto fail;
}
if (device_info.num_regions < VFIO_PCI_CONFIG_REGION_INDEX) {
error_setg(errp, "Invalid device regions");
ret = -EINVAL;
goto fail;
}
s->config_region_info = (struct vfio_region_info) {
.index = VFIO_PCI_CONFIG_REGION_INDEX,
.argsz = sizeof(struct vfio_region_info),
};
if (ioctl(s->device, VFIO_DEVICE_GET_REGION_INFO, &s->config_region_info)) {
error_setg_errno(errp, errno, "Failed to get config region info");
ret = -errno;
goto fail;
}
for (i = 0; i < ARRAY_SIZE(s->bar_region_info); i++) {
ret = qemu_vfio_pci_init_bar(s, i, errp);
if (ret) {
goto fail;
}
}
/* Enable bus master */
ret = qemu_vfio_pci_read_config(s, &pci_cmd, sizeof(pci_cmd), PCI_COMMAND);
if (ret) {
goto fail;
}
pci_cmd |= PCI_COMMAND_MASTER;
ret = qemu_vfio_pci_write_config(s, &pci_cmd, sizeof(pci_cmd), PCI_COMMAND);
if (ret) {
goto fail;
}
return 0;
fail:
close(s->group);
fail_container:
close(s->container);
return ret;
}
static void qemu_vfio_ram_block_added(RAMBlockNotifier *n,
void *host, size_t size)
{
QEMUVFIOState *s = container_of(n, QEMUVFIOState, ram_notifier);
trace_qemu_vfio_ram_block_added(s, host, size);
qemu_vfio_dma_map(s, host, size, false, NULL);
}
static void qemu_vfio_ram_block_removed(RAMBlockNotifier *n,
void *host, size_t size)
{
QEMUVFIOState *s = container_of(n, QEMUVFIOState, ram_notifier);
if (host) {
trace_qemu_vfio_ram_block_removed(s, host, size);
qemu_vfio_dma_unmap(s, host);
}
}
static int qemu_vfio_init_ramblock(const char *block_name, void *host_addr,
ram_addr_t offset, ram_addr_t length,
void *opaque)
{
int ret;
QEMUVFIOState *s = opaque;
if (!host_addr) {
return 0;
}
ret = qemu_vfio_dma_map(s, host_addr, length, false, NULL);
if (ret) {
fprintf(stderr, "qemu_vfio_init_ramblock: failed %p %" PRId64 "\n",
host_addr, (uint64_t)length);
}
return 0;
}
static void qemu_vfio_open_common(QEMUVFIOState *s)
{
qemu_mutex_init(&s->lock);
s->ram_notifier.ram_block_added = qemu_vfio_ram_block_added;
s->ram_notifier.ram_block_removed = qemu_vfio_ram_block_removed;
ram_block_notifier_add(&s->ram_notifier);
s->low_water_mark = QEMU_VFIO_IOVA_MIN;
s->high_water_mark = QEMU_VFIO_IOVA_MAX;
qemu_ram_foreach_block(qemu_vfio_init_ramblock, s);
}
/**
* Open a PCI device, e.g. "0000:00:01.0".
*/
QEMUVFIOState *qemu_vfio_open_pci(const char *device, Error **errp)
{
int r;
QEMUVFIOState *s = g_new0(QEMUVFIOState, 1);
r = qemu_vfio_init_pci(s, device, errp);
if (r) {
g_free(s);
return NULL;
}
qemu_vfio_open_common(s);
return s;
}
static void qemu_vfio_dump_mapping(IOVAMapping *m)
{
if (QEMU_VFIO_DEBUG) {
printf(" vfio mapping %p %" PRIx64 " to %" PRIx64 "\n", m->host,
(uint64_t)m->size, (uint64_t)m->iova);
}
}
static void qemu_vfio_dump_mappings(QEMUVFIOState *s)
{
int i;
if (QEMU_VFIO_DEBUG) {
printf("vfio mappings\n");
for (i = 0; i < s->nr_mappings; ++i) {
qemu_vfio_dump_mapping(&s->mappings[i]);
}
}
}
/**
* Find the mapping entry that contains [host, host + size) and set @index to
* the position. If no entry contains it, @index is the position _after_ which
* to insert the new mapping. IOW, it is the index of the largest element that
* is smaller than @host, or -1 if no entry is.
*/
static IOVAMapping *qemu_vfio_find_mapping(QEMUVFIOState *s, void *host,
int *index)
{
IOVAMapping *p = s->mappings;
IOVAMapping *q = p ? p + s->nr_mappings - 1 : NULL;
IOVAMapping *mid;
trace_qemu_vfio_find_mapping(s, host);
if (!p) {
*index = -1;
return NULL;
}
while (true) {
mid = p + (q - p) / 2;
if (mid == p) {
break;
}
if (mid->host > host) {
q = mid;
} else if (mid->host < host) {
p = mid;
} else {
break;
}
}
if (mid->host > host) {
mid--;
} else if (mid < &s->mappings[s->nr_mappings - 1]
&& (mid + 1)->host <= host) {
mid++;
}
*index = mid - &s->mappings[0];
if (mid >= &s->mappings[0] &&
mid->host <= host && mid->host + mid->size > host) {
assert(mid < &s->mappings[s->nr_mappings]);
return mid;
}
/* At this point *index + 1 is the right position to insert the new
* mapping.*/
return NULL;
}
/**
* Allocate IOVA and and create a new mapping record and insert it in @s.
*/
static IOVAMapping *qemu_vfio_add_mapping(QEMUVFIOState *s,
void *host, size_t size,
int index, uint64_t iova)
{
int shift;
IOVAMapping m = {.host = host, .size = size, .iova = iova};
IOVAMapping *insert;
assert(QEMU_IS_ALIGNED(size, getpagesize()));
assert(QEMU_IS_ALIGNED(s->low_water_mark, getpagesize()));
assert(QEMU_IS_ALIGNED(s->high_water_mark, getpagesize()));
trace_qemu_vfio_new_mapping(s, host, size, index, iova);
assert(index >= 0);
s->nr_mappings++;
s->mappings = g_renew(IOVAMapping, s->mappings, s->nr_mappings);
insert = &s->mappings[index];
shift = s->nr_mappings - index - 1;
if (shift) {
memmove(insert + 1, insert, shift * sizeof(s->mappings[0]));
}
*insert = m;
return insert;
}
/* Do the DMA mapping with VFIO. */
static int qemu_vfio_do_mapping(QEMUVFIOState *s, void *host, size_t size,
uint64_t iova)
{
struct vfio_iommu_type1_dma_map dma_map = {
.argsz = sizeof(dma_map),
.flags = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE,
.iova = iova,
.vaddr = (uintptr_t)host,
.size = size,
};
trace_qemu_vfio_do_mapping(s, host, size, iova);
if (ioctl(s->container, VFIO_IOMMU_MAP_DMA, &dma_map)) {
error_report("VFIO_MAP_DMA: %d", -errno);
return -errno;
}
return 0;
}
/**
* Undo the DMA mapping from @s with VFIO, and remove from mapping list.
*/
static void qemu_vfio_undo_mapping(QEMUVFIOState *s, IOVAMapping *mapping,
Error **errp)
{
int index;
struct vfio_iommu_type1_dma_unmap unmap = {
.argsz = sizeof(unmap),
.flags = 0,
.iova = mapping->iova,
.size = mapping->size,
};
index = mapping - s->mappings;
assert(mapping->size > 0);
assert(QEMU_IS_ALIGNED(mapping->size, getpagesize()));
assert(index >= 0 && index < s->nr_mappings);
if (ioctl(s->container, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
error_setg(errp, "VFIO_UNMAP_DMA failed: %d", -errno);
}
memmove(mapping, &s->mappings[index + 1],
sizeof(s->mappings[0]) * (s->nr_mappings - index - 1));
s->nr_mappings--;
s->mappings = g_renew(IOVAMapping, s->mappings, s->nr_mappings);
}
/* Check if the mapping list is (ascending) ordered. */
static bool qemu_vfio_verify_mappings(QEMUVFIOState *s)
{
int i;
if (QEMU_VFIO_DEBUG) {
for (i = 0; i < s->nr_mappings - 1; ++i) {
if (!(s->mappings[i].host < s->mappings[i + 1].host)) {
fprintf(stderr, "item %d not sorted!\n", i);
qemu_vfio_dump_mappings(s);
return false;
}
if (!(s->mappings[i].host + s->mappings[i].size <=
s->mappings[i + 1].host)) {
fprintf(stderr, "item %d overlap with next!\n", i);
qemu_vfio_dump_mappings(s);
return false;
}
}
}
return true;
}
/* Map [host, host + size) area into a contiguous IOVA address space, and store
* the result in @iova if not NULL. The caller need to make sure the area is
* aligned to page size, and mustn't overlap with existing mapping areas (split
* mapping status within this area is not allowed).
*/
int qemu_vfio_dma_map(QEMUVFIOState *s, void *host, size_t size,
bool temporary, uint64_t *iova)
{
int ret = 0;
int index;
IOVAMapping *mapping;
uint64_t iova0;
assert(QEMU_PTR_IS_ALIGNED(host, getpagesize()));
assert(QEMU_IS_ALIGNED(size, getpagesize()));
trace_qemu_vfio_dma_map(s, host, size, temporary, iova);
qemu_mutex_lock(&s->lock);
mapping = qemu_vfio_find_mapping(s, host, &index);
if (mapping) {
iova0 = mapping->iova + ((uint8_t *)host - (uint8_t *)mapping->host);
} else {
if (s->high_water_mark - s->low_water_mark + 1 < size) {
ret = -ENOMEM;
goto out;
}
if (!temporary) {
iova0 = s->low_water_mark;
mapping = qemu_vfio_add_mapping(s, host, size, index + 1, iova0);
if (!mapping) {
ret = -ENOMEM;
goto out;
}
assert(qemu_vfio_verify_mappings(s));
ret = qemu_vfio_do_mapping(s, host, size, iova0);
if (ret) {
qemu_vfio_undo_mapping(s, mapping, NULL);
goto out;
}
s->low_water_mark += size;
qemu_vfio_dump_mappings(s);
} else {
iova0 = s->high_water_mark - size;
ret = qemu_vfio_do_mapping(s, host, size, iova0);
if (ret) {
goto out;
}
s->high_water_mark -= size;
}
}
if (iova) {
*iova = iova0;
}
out:
qemu_mutex_unlock(&s->lock);
return ret;
}
/* Reset the high watermark and free all "temporary" mappings. */
int qemu_vfio_dma_reset_temporary(QEMUVFIOState *s)
{
struct vfio_iommu_type1_dma_unmap unmap = {
.argsz = sizeof(unmap),
.flags = 0,
.iova = s->high_water_mark,
.size = QEMU_VFIO_IOVA_MAX - s->high_water_mark,
};
trace_qemu_vfio_dma_reset_temporary(s);
qemu_mutex_lock(&s->lock);
if (ioctl(s->container, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
error_report("VFIO_UNMAP_DMA: %d", -errno);
qemu_mutex_unlock(&s->lock);
return -errno;
}
s->high_water_mark = QEMU_VFIO_IOVA_MAX;
qemu_mutex_unlock(&s->lock);
return 0;
}
/* Unmapping the whole area that was previously mapped with
* qemu_vfio_dma_map(). */
void qemu_vfio_dma_unmap(QEMUVFIOState *s, void *host)
{
int index = 0;
IOVAMapping *m;
if (!host) {
return;
}
trace_qemu_vfio_dma_unmap(s, host);
qemu_mutex_lock(&s->lock);
m = qemu_vfio_find_mapping(s, host, &index);
if (!m) {
goto out;
}
qemu_vfio_undo_mapping(s, m, NULL);
out:
qemu_mutex_unlock(&s->lock);
}
static void qemu_vfio_reset(QEMUVFIOState *s)
{
ioctl(s->device, VFIO_DEVICE_RESET);
}
/* Close and free the VFIO resources. */
void qemu_vfio_close(QEMUVFIOState *s)
{
int i;
if (!s) {
return;
}
for (i = 0; i < s->nr_mappings; ++i) {
qemu_vfio_undo_mapping(s, &s->mappings[i], NULL);
}
ram_block_notifier_remove(&s->ram_notifier);
qemu_vfio_reset(s);
close(s->device);
close(s->group);
close(s->container);
}
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