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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"
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;
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(lm_ctx_t *lm_ctx, int max_regions)
{
dma_controller_t *dma;
dma = malloc(offsetof(dma_controller_t, regions) +
max_regions * sizeof(dma->regions[0]));
if (dma == NULL) {
return dma;
}
dma->lm_ctx = lm_ctx;
dma->max_regions = max_regions;
dma->nregions = 0;
memset(dma->regions, 0, max_regions * sizeof(dma->regions[0]));
dma->dirty_pgsize = 0;
return dma;
}
static void
_dma_controller_do_remove_region(dma_controller_t *dma,
dma_memory_region_t *region)
{
int err;
assert(dma != NULL);
assert(region != NULL);
err = dma_unmap_region(region, region->virt_addr, region->size);
if (err != 0) {
lm_log(dma->lm_ctx, LM_DBG, "failed to unmap fd=%d vaddr=%#lx-%#lx\n",
region->fd, region->virt_addr, region->size);
}
if (region->fd != -1) {
if (close(region->fd) == -1) {
lm_log(dma->lm_ctx, LM_DBG, "failed to close fd %d: %m\n", region->fd);
}
}
}
/*
* FIXME no longer used. Also, it doesn't work for addresses that span two
* DMA regions.
*/
bool
dma_controller_region_valid(dma_controller_t *dma, dma_addr_t dma_addr,
size_t size)
{
dma_memory_region_t *region;
int i;
for (i = 0; i < dma->nregions; i++) {
region = &dma->regions[i];
if (dma_addr == region->dma_addr && size <= region->size) {
return true;
}
}
return false;
}
/* FIXME not thread safe */
int
dma_controller_remove_region(dma_controller_t *dma,
dma_addr_t dma_addr, size_t size,
int (*unmap_dma) (void*, uint64_t), void *data)
{
int idx;
dma_memory_region_t *region;
int err;
assert(dma != NULL);
for (idx = 0; idx < dma->nregions; idx++) {
region = &dma->regions[idx];
if (region->dma_addr == dma_addr && region->size == size) {
if (region->refcnt > 0) {
err = unmap_dma(data, region->dma_addr);
if (err != 0) {
lm_log(dma->lm_ctx, LM_ERR,
"failed to notify of removal of DMA region %#lx-%#lx: %s\n",
region->dma_addr, region->dma_addr + region->size,
strerror(-err));
return err;
}
assert(region->refcnt == 0);
}
_dma_controller_do_remove_region(dma, region);
if (dma->nregions > 1)
/*
* FIXME valgrind complains with 'Source and destination overlap in memcpy',
* check whether memmove eliminates this warning.
*/
memcpy(region, &dma->regions[dma->nregions - 1],
sizeof *region);
dma->nregions--;
return 0;
}
}
return -ENOENT;
}
static inline void
dma_controller_remove_regions(dma_controller_t *dma)
{
int i;
assert(dma);
for (i = 0; i < dma->nregions; i++) {
dma_memory_region_t *region = &dma->regions[i];
lm_log(dma->lm_ctx, LM_INF, "unmap vaddr=%#lx IOVA=%#lx",
region->virt_addr, region->dma_addr);
_dma_controller_do_remove_region(dma, region);
}
}
void
dma_controller_destroy(dma_controller_t *dma)
{
if (dma == NULL) {
return;
}
dma_controller_remove_regions(dma);
free(dma);
}
int
dma_controller_add_region(dma_controller_t *dma,
dma_addr_t dma_addr, size_t size,
int fd, off_t offset)
{
int idx;
dma_memory_region_t *region;
int page_size;
for (idx = 0; idx < dma->nregions; idx++) {
region = &dma->regions[idx];
/* First check if this is the same exact region. */
if (region->dma_addr == dma_addr && region->size == size) {
if (offset != region->offset) {
lm_log(dma->lm_ctx, LM_ERR,
"bad offset for new DMA region %#lx+%#lx, want=%d, existing=%d\n",
dma_addr, size, offset, region->offset);
goto err;
}
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.
*/
lm_log(dma->lm_ctx, LM_ERR,
"bad fd=%d for new DMA region %#lx-%#lx, existing fd=%d\n",
fd, region->fd);
goto err;
}
return idx;
}
/* Check for overlap, i.e. start of one region is within another. */
if ((dma_addr >= region->dma_addr &&
dma_addr < region->dma_addr + region->size) ||
(region->dma_addr >= dma_addr &&
region->dma_addr < dma_addr + size)) {
lm_log(dma->lm_ctx, LM_INF,
"new DMA region %#lx+%#lx overlaps with DMA region %#lx-%#lx\n",
dma_addr, size, region->dma_addr, region->size);
goto err;
}
}
if (dma->nregions == dma->max_regions) {
idx = dma->max_regions;
lm_log(dma->lm_ctx, LM_ERR,
"reached maxed regions, recompile with higher number of DMA regions\n");
goto err;
}
idx = dma->nregions;
region = &dma->regions[idx];
page_size = fd_get_blocksize(fd);
if (page_size < 0) {
lm_log(dma->lm_ctx, LM_ERR, "bad page size %d\n", page_size);
goto err;
}
page_size = MAX(page_size, getpagesize());
region->dma_addr = dma_addr;
region->size = size;
region->page_size = page_size;
region->offset = offset;
region->fd = fd;
region->refcnt = 0;
region->virt_addr = dma_map_region(region, PROT_READ | PROT_WRITE,
0, region->size);
if (region->virt_addr == MAP_FAILED) {
lm_log(dma->lm_ctx, LM_ERR,
"failed to memory map DMA region %#lx-%#lx: %s\n",
dma_addr, dma_addr + size, strerror(errno));
if (region->fd != -1) {
if (close(region->fd) == -1) {
lm_log(dma->lm_ctx, LM_DBG, "failed to close fd %d: %m\n",
region->fd);
}
}
goto err;
}
dma->nregions++;
return idx;
err:
return -idx - 1;
}
static inline void
mmap_round(size_t *offset, size_t *size, size_t page_size)
{
size_t offset_orig = *offset;
*offset = ROUND_DOWN(offset_orig, page_size);
*size = ROUND_UP(offset_orig + *size, page_size) - *offset;
}
void *
dma_map_region(dma_memory_region_t *region, int prot, size_t offset, size_t len)
{
size_t mmap_offset, mmap_size = len;
char *mmap_base;
if (offset >= region->size || offset + len > region->size) {
return MAP_FAILED;
}
offset += region->offset;
mmap_offset = offset;
mmap_round(&mmap_offset, &mmap_size, region->page_size);
// Do the mmap.
mmap_base = mmap(NULL, mmap_size, prot, MAP_SHARED,
region->fd, mmap_offset);
if (mmap_base == MAP_FAILED) {
return mmap_base;
}
// Do not dump.
madvise(mmap_base, mmap_size, MADV_DONTDUMP);
return mmap_base + (offset - mmap_offset);
}
int
dma_unmap_region(dma_memory_region_t *region, void *virt_addr, size_t len)
{
mmap_round((size_t *)&virt_addr, &len, region->page_size);
return munmap(virt_addr, len);
}
int
_dma_addr_sg_split(const dma_controller_t *dma,
dma_addr_t dma_addr, uint32_t len,
dma_sg_t *sg, int max_sg, int prot)
{
int idx;
int cnt = 0;
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];
const dma_addr_t region_end = region->dma_addr + region->size;
while (dma_addr >= region->dma_addr && dma_addr < region_end) {
size_t region_len = MIN(region_end - dma_addr, len);
if (cnt < max_sg) {
sg[cnt].dma_addr = region->dma_addr;
sg[cnt].region = idx;
sg[cnt].offset = dma_addr - region->dma_addr;
sg[cnt].length = region_len;
if (_dma_should_mark_dirty(dma, prot)) {
_dma_mark_dirty(dma, region, sg);
}
}
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);
cnt = -1;
} else if (cnt > max_sg) {
cnt = -cnt - 1;
}
return cnt;
}
ssize_t _get_bitmap_size(size_t region_size, size_t pgsize)
{
if (pgsize == 0) {
return -EINVAL;
}
if (region_size < pgsize) {
return -EINVAL;
}
size_t nr_pages = (region_size / pgsize) + (region_size % pgsize != 0);
return (nr_pages / CHAR_BIT) + (nr_pages % CHAR_BIT != 0);
}
int dma_controller_dirty_page_logging_start(dma_controller_t *dma, size_t pgsize)
{
int i;
assert(dma != NULL);
if (pgsize == 0) {
return -EINVAL;
}
if (dma->dirty_pgsize > 0) {
if (dma->dirty_pgsize != pgsize) {
return -EINVAL;
}
return 0;
}
for (i = 0; i < dma->nregions; i++) {
dma_memory_region_t *region = &dma->regions[i];
ssize_t bitmap_size = _get_bitmap_size(region->size, pgsize);
if (bitmap_size < 0) {
return bitmap_size;
}
region->dirty_bitmap = calloc(bitmap_size, sizeof(char));
if (region->dirty_bitmap == NULL) {
int j, ret = -errno;
for (j = 0; j < i; j++) {
free(region->dirty_bitmap);
region->dirty_bitmap = NULL;
}
return ret;
}
}
dma->dirty_pgsize = pgsize;
return 0;
}
int dma_controller_dirty_page_logging_stop(dma_controller_t *dma)
{
int i;
assert(dma != NULL);
if (dma->dirty_pgsize == 0) {
return 0;
}
for (i = 0; i < dma->nregions; i++) {
free(dma->regions[i].dirty_bitmap);
dma->regions[i].dirty_bitmap = NULL;
}
dma->dirty_pgsize = 0;
return 0;
}
int
dma_controller_dirty_page_get(dma_controller_t *dma, dma_addr_t addr, int len,
size_t pgsize, size_t size, char **data)
{
int ret;
ssize_t bitmap_size;
dma_sg_t sg;
dma_memory_region_t *region;
assert(dma != NULL);
assert(data != 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 -ENOTSUP;
}
if (pgsize != dma->dirty_pgsize) {
return -EINVAL;
}
bitmap_size = _get_bitmap_size(len, pgsize);
if (bitmap_size < 0) {
return bitmap_size;
}
/*
* FIXME they must be equal because this is how much data the client
* expects to receive.
*/
if (size != (size_t)bitmap_size) {
return -EINVAL;
}
region = &dma->regions[sg.region];
*data = region->dirty_bitmap;
return 0;
}
/* ex: set tabstop=4 shiftwidth=4 softtabstop=4 expandtab: */
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