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/*
* Copyright (c) 2019 Nutanix Inc. All rights reserved.
*
* Authors: Mike Cui <cui@nutanix.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Nutanix nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/param.h>
#include <stddef.h>
#include <stdbool.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include "dma.h"
#include "private.h"
EXPORT size_t
dma_sg_size(void)
{
return sizeof(dma_sg_t);
}
bool
dma_sg_is_mappable(const dma_controller_t *dma, const dma_sg_t *sg) {
return sg->region[dma->regions].info.vaddr != NULL;
}
static inline ssize_t
fd_get_blocksize(int fd)
{
struct stat st;
if (fstat(fd, &st) != 0)
return -1;
return st.st_blksize;
}
/* Returns true if 2 fds refer to the same file.
If any fd is invalid, return false. */
static inline bool
fds_are_same_file(int fd1, int fd2)
{
struct stat st1, st2;
if (fd1 == fd2) {
return true;
}
return (fstat(fd1, &st1) == 0 && fstat(fd2, &st2) == 0 &&
st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);
}
dma_controller_t *
dma_controller_create(vfu_ctx_t *vfu_ctx, size_t max_regions, size_t max_size)
{
dma_controller_t *dma;
dma = malloc(offsetof(dma_controller_t, regions) +
max_regions * sizeof(dma->regions[0]));
if (dma == NULL) {
return dma;
}
dma->vfu_ctx = vfu_ctx;
dma->max_regions = (int)max_regions;
dma->max_size = max_size;
dma->nregions = 0;
memset(dma->regions, 0, max_regions * sizeof(dma->regions[0]));
dma->dirty_pgsize = 0;
return dma;
}
void
MOCK_DEFINE(dma_controller_unmap_region)(dma_controller_t *dma,
dma_memory_region_t *region)
{
int err;
assert(dma != NULL);
assert(region != NULL);
err = munmap(region->info.mapping.iov_base, region->info.mapping.iov_len);
if (err != 0) {
vfu_log(dma->vfu_ctx, LOG_DEBUG, "failed to unmap fd=%d "
"mapping=[%p, %p): %m",
region->fd, region->info.mapping.iov_base,
iov_end(®ion->info.mapping));
}
assert(region->fd != -1);
if (close(region->fd) == -1) {
vfu_log(dma->vfu_ctx, LOG_WARNING, "failed to close fd %d: %m",
region->fd);
}
}
static void
array_remove(void *array, size_t elem_size, size_t index, int *nr_elemsp)
{
void *dest;
void *src;
size_t nr;
assert((size_t)*nr_elemsp > index);
nr = *nr_elemsp - (index + 1);
dest = (char *)array + (index * elem_size);
src = (char *)array + ((index + 1) * elem_size);
memmove(dest, src, nr * elem_size);
(*nr_elemsp)--;
}
/* FIXME not thread safe */
int
MOCK_DEFINE(dma_controller_remove_region)(dma_controller_t *dma,
vfu_dma_addr_t dma_addr, size_t size,
vfu_dma_unregister_cb_t *dma_unregister,
void *data)
{
int idx;
dma_memory_region_t *region;
assert(dma != NULL);
for (idx = 0; idx < dma->nregions; idx++) {
region = &dma->regions[idx];
if (region->info.iova.iov_base != dma_addr ||
region->info.iova.iov_len != size) {
continue;
}
if (dma_unregister != NULL) {
dma->vfu_ctx->in_cb = CB_DMA_UNREGISTER;
dma_unregister(data, ®ion->info);
dma->vfu_ctx->in_cb = CB_NONE;
}
if (region->info.vaddr != NULL) {
dma_controller_unmap_region(dma, region);
} else {
assert(region->fd == -1);
}
array_remove(&dma->regions, sizeof (*region), idx, &dma->nregions);
return 0;
}
return ERROR_INT(ENOENT);
}
void
dma_controller_remove_all_regions(dma_controller_t *dma,
vfu_dma_unregister_cb_t *dma_unregister,
void *data)
{
int i;
assert(dma != NULL);
for (i = 0; i < dma->nregions; i++) {
dma_memory_region_t *region = &dma->regions[i];
vfu_log(dma->vfu_ctx, LOG_DEBUG, "removing DMA region "
"iova=[%p, %p) vaddr=%p mapping=[%p, %p)",
region->info.iova.iov_base, iov_end(®ion->info.iova),
region->info.vaddr,
region->info.mapping.iov_base, iov_end(®ion->info.mapping));
if (dma_unregister != NULL) {
dma->vfu_ctx->in_cb = CB_DMA_UNREGISTER;
dma_unregister(data, ®ion->info);
dma->vfu_ctx->in_cb = CB_NONE;
}
if (region->info.vaddr != NULL) {
dma_controller_unmap_region(dma, region);
} else {
assert(region->fd == -1);
}
}
memset(dma->regions, 0, dma->max_regions * sizeof(dma->regions[0]));
dma->nregions = 0;
}
void
dma_controller_destroy(dma_controller_t *dma)
{
assert(dma->nregions == 0);
free(dma);
}
static int
dma_map_region(dma_controller_t *dma, dma_memory_region_t *region)
{
void *mmap_base;
size_t mmap_len;
off_t offset;
offset = ROUND_DOWN(region->offset, region->info.page_size);
mmap_len = ROUND_UP(region->info.iova.iov_len, region->info.page_size);
mmap_base = mmap(NULL, mmap_len, region->info.prot, MAP_SHARED,
region->fd, offset);
if (mmap_base == MAP_FAILED) {
return -1;
}
// Do not dump.
madvise(mmap_base, mmap_len, MADV_DONTDUMP);
region->info.mapping.iov_base = mmap_base;
region->info.mapping.iov_len = mmap_len;
region->info.vaddr = mmap_base + (region->offset - offset);
vfu_log(dma->vfu_ctx, LOG_DEBUG, "mapped DMA region iova=[%p, %p) "
"vaddr=%p page_size=%#lx mapping=[%p, %p)",
region->info.iova.iov_base, iov_end(®ion->info.iova),
region->info.vaddr, region->info.page_size,
region->info.mapping.iov_base, iov_end(®ion->info.mapping));
return 0;
}
static ssize_t
get_bitmap_size(size_t region_size, size_t pgsize)
{
if (pgsize == 0) {
return ERROR_INT(EINVAL);
}
if (region_size < pgsize) {
return ERROR_INT(EINVAL);
}
return _get_bitmap_size(region_size, pgsize);
}
static int
dirty_page_logging_start_on_region(dma_memory_region_t *region, size_t pgsize)
{
assert(region->fd != -1);
ssize_t size = get_bitmap_size(region->info.iova.iov_len, pgsize);
if (size < 0) {
return size;
}
region->dirty_bitmap = calloc(size, sizeof(char));
if (region->dirty_bitmap == NULL) {
return ERROR_INT(errno);
}
return 0;
}
int
MOCK_DEFINE(dma_controller_add_region)(dma_controller_t *dma,
vfu_dma_addr_t dma_addr, size_t size,
int fd, off_t offset, uint32_t prot)
{
dma_memory_region_t *region;
int page_size = 0;
char rstr[1024];
int idx;
assert(dma != NULL);
snprintf(rstr, sizeof(rstr), "[%p, %p) fd=%d offset=%#lx prot=%#x",
dma_addr, (char *)dma_addr + size, fd, offset, prot);
if (size > dma->max_size) {
vfu_log(dma->vfu_ctx, LOG_ERR, "DMA region size %zu > max %zu",
size, dma->max_size);
return ERROR_INT(ENOSPC);
}
for (idx = 0; idx < dma->nregions; idx++) {
region = &dma->regions[idx];
/* First check if this is the same exact region. */
if (region->info.iova.iov_base == dma_addr &&
region->info.iova.iov_len == size) {
if (offset != region->offset) {
vfu_log(dma->vfu_ctx, LOG_ERR, "bad offset for new DMA region "
"%s; existing=%#lx", rstr, region->offset);
return ERROR_INT(EINVAL);
}
if (!fds_are_same_file(region->fd, fd)) {
/*
* Printing the file descriptors here doesn't really make
* sense as they can be different but actually pointing to
* the same file, however in the majority of cases we'll be
* using a single fd.
*/
vfu_log(dma->vfu_ctx, LOG_ERR, "bad fd for new DMA region %s; "
"existing=%d", rstr, region->fd);
return ERROR_INT(EINVAL);
}
if (region->info.prot != prot) {
vfu_log(dma->vfu_ctx, LOG_ERR, "bad prot for new DMA region "
"%s; existing=%#x", rstr, region->info.prot);
return ERROR_INT(EINVAL);
}
return idx;
}
/* Check for overlap, i.e. start of one region is within another. */
if ((dma_addr >= region->info.iova.iov_base &&
dma_addr < iov_end(®ion->info.iova)) ||
(region->info.iova.iov_base >= dma_addr &&
region->info.iova.iov_base < dma_addr + size)) {
vfu_log(dma->vfu_ctx, LOG_INFO, "new DMA region %s overlaps with "
"DMA region [%p, %p)", rstr, region->info.iova.iov_base,
iov_end(®ion->info.iova));
return ERROR_INT(EINVAL);
}
}
if (dma->nregions == dma->max_regions) {
vfu_log(dma->vfu_ctx, LOG_ERR, "hit max regions %d", dma->max_regions);
return ERROR_INT(EINVAL);
}
idx = dma->nregions;
region = &dma->regions[idx];
if (fd != -1) {
page_size = fd_get_blocksize(fd);
if (page_size < 0) {
vfu_log(dma->vfu_ctx, LOG_ERR, "bad page size %d", page_size);
return ERROR_INT(EINVAL);
}
}
page_size = MAX(page_size, getpagesize());
memset(region, 0, sizeof (*region));
region->info.iova.iov_base = (void *)dma_addr;
region->info.iova.iov_len = size;
region->info.page_size = page_size;
region->info.prot = prot;
region->offset = offset;
region->fd = fd;
if (fd != -1) {
int ret;
/*
* TODO introduce a function that tells whether dirty page logging is
* enabled
*/
if (dma->dirty_pgsize != 0) {
if (dirty_page_logging_start_on_region(region, dma->dirty_pgsize) < 0) {
/*
* TODO We don't necessarily have to fail, we can continue
* and fail the get dirty page bitmap request later.
*/
return -1;
}
}
ret = dma_map_region(dma, region);
if (ret != 0) {
ret = errno;
vfu_log(dma->vfu_ctx, LOG_ERR,
"failed to memory map DMA region %s: %m", rstr);
if (close(region->fd) == -1) {
vfu_log(dma->vfu_ctx, LOG_WARNING,
"failed to close fd %d: %m", region->fd);
}
free(region->dirty_bitmap);
return ERROR_INT(ret);
}
}
dma->nregions++;
return idx;
}
int
_dma_addr_sg_split(const dma_controller_t *dma,
vfu_dma_addr_t dma_addr, uint64_t len,
dma_sg_t *sg, int max_sg, int prot)
{
int idx;
int cnt = 0, ret;
bool found = true; // Whether the current region is found.
while (found && len > 0) {
found = false;
for (idx = 0; idx < dma->nregions; idx++) {
const dma_memory_region_t *const region = &dma->regions[idx];
vfu_dma_addr_t region_start = region->info.iova.iov_base;
vfu_dma_addr_t region_end = iov_end(®ion->info.iova);
while (dma_addr >= region_start && dma_addr < region_end) {
size_t region_len = MIN((uint64_t)(region_end - dma_addr), len);
if (cnt < max_sg) {
ret = dma_init_sg(dma, &sg[cnt], dma_addr, region_len, prot, idx);
if (ret < 0) {
return ret;
}
}
cnt++;
// dma_addr found, may need to start from the top for the
// next dma_addr.
found = true;
dma_addr += region_len;
len -= region_len;
if (len == 0) {
goto out;
}
}
}
}
out:
if (!found) {
// There is still a region which was not found.
assert(len > 0);
return ERROR_INT(ENOENT);
} else if (cnt > max_sg) {
cnt = -cnt - 1;
}
errno = 0;
return cnt;
}
int
dma_controller_dirty_page_logging_start(dma_controller_t *dma, size_t pgsize)
{
size_t i;
assert(dma != NULL);
if (pgsize == 0) {
return ERROR_INT(EINVAL);
}
if (dma->dirty_pgsize > 0) {
if (dma->dirty_pgsize != pgsize) {
return ERROR_INT(EINVAL);
}
return 0;
}
for (i = 0; i < (size_t)dma->nregions; i++) {
dma_memory_region_t *region = &dma->regions[i];
if (region->fd == -1) {
continue;
}
if (dirty_page_logging_start_on_region(region, pgsize) < 0) {
int _errno = errno;
size_t j;
for (j = 0; j < i; j++) {
region = &dma->regions[j];
free(region->dirty_bitmap);
region->dirty_bitmap = NULL;
}
return ERROR_INT(_errno);
}
}
dma->dirty_pgsize = pgsize;
vfu_log(dma->vfu_ctx, LOG_DEBUG, "dirty pages: started logging");
return 0;
}
void
dma_controller_dirty_page_logging_stop(dma_controller_t *dma)
{
int i;
assert(dma != NULL);
if (dma->dirty_pgsize == 0) {
return;
}
for (i = 0; i < dma->nregions; i++) {
free(dma->regions[i].dirty_bitmap);
dma->regions[i].dirty_bitmap = NULL;
}
dma->dirty_pgsize = 0;
vfu_log(dma->vfu_ctx, LOG_DEBUG, "dirty pages: stopped logging");
}
#ifdef DEBUG
static void
log_dirty_bitmap(vfu_ctx_t *vfu_ctx, dma_memory_region_t *region,
char *bitmap, size_t size)
{
size_t i;
size_t count;
for (i = 0, count = 0; i < size; i++) {
count += __builtin_popcount(bitmap[i]);
}
vfu_log(vfu_ctx, LOG_DEBUG, "dirty pages: get [%p, %p), %zu dirty pages",
region->info.iova.iov_base, iov_end(®ion->info.iova),
count);
}
#endif
int
dma_controller_dirty_page_get(dma_controller_t *dma, vfu_dma_addr_t addr,
uint64_t len, size_t pgsize, size_t size,
char *bitmap)
{
int ret;
ssize_t bitmap_size;
dma_sg_t sg;
dma_memory_region_t *region;
assert(dma != NULL);
assert(bitmap != NULL);
/*
* FIXME for now we support IOVAs that match exactly the DMA region. This
* is purely for simplifying the implementation. We MUST allow arbitrary
* IOVAs.
*/
ret = dma_addr_to_sg(dma, addr, len, &sg, 1, PROT_NONE);
if (ret != 1 || sg.dma_addr != addr || sg.length != len) {
return ERROR_INT(ENOTSUP);
}
if (pgsize != dma->dirty_pgsize) {
vfu_log(dma->vfu_ctx, LOG_ERR, "bad page size %ld", pgsize);
return ERROR_INT(EINVAL);
}
bitmap_size = get_bitmap_size(len, pgsize);
if (bitmap_size < 0) {
vfu_log(dma->vfu_ctx, LOG_ERR, "failed to get bitmap size");
return bitmap_size;
}
/*
* They must be equal because this is how much data the client expects to
* receive.
*/
if (size != (size_t)bitmap_size) {
vfu_log(dma->vfu_ctx, LOG_ERR, "bad bitmap size %ld != %ld", size,
bitmap_size);
return ERROR_INT(EINVAL);
}
region = &dma->regions[sg.region];
if (region->fd == -1) {
vfu_log(dma->vfu_ctx, LOG_ERR, "region %d is not mapped", sg.region);
return ERROR_INT(EINVAL);
}
/*
* TODO race condition between resetting bitmap and user calling
* vfu_map_sg/vfu_unmap_sg().
*/
memcpy(bitmap, region->dirty_bitmap, size);
#ifdef DEBUG
log_dirty_bitmap(dma->vfu_ctx, region, bitmap, size);
#endif
memset(region->dirty_bitmap, 0, size);
return 0;
}
/* ex: set tabstop=4 shiftwidth=4 softtabstop=4 expandtab: */
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