diff options
Diffstat (limited to 'samples/server.c')
-rw-r--r-- | samples/server.c | 207 |
1 files changed, 73 insertions, 134 deletions
diff --git a/samples/server.c b/samples/server.c index 565974d..5edf674 100644 --- a/samples/server.c +++ b/samples/server.c @@ -60,7 +60,7 @@ struct server_data { size_t bar1_size; struct dma_regions regions[NR_DMA_REGIONS]; struct { - uint64_t pending_bytes; + uint64_t bytes_transferred; vfu_migr_state_t state; } migration; }; @@ -130,10 +130,6 @@ bar1_access(vfu_ctx_t *vfu_ctx, char * const buf, } if (is_write) { - if (server_data->migration.state == VFU_MIGR_STATE_PRE_COPY) { - /* dirty the whole thing */ - server_data->migration.pending_bytes = server_data->bar1_size; - } memcpy(server_data->bar1 + offset, buf, count); } else { memcpy(buf, server_data->bar1, count); @@ -322,19 +318,24 @@ migration_device_state_transition(vfu_ctx_t *vfu_ctx, vfu_migr_state_t state) if (setitimer(ITIMER_REAL, &new, NULL) != 0) { err(EXIT_FAILURE, "failed to disable timer"); } - server_data->migration.pending_bytes = server_data->bar1_size + sizeof(time_t); /* FIXME BAR0 region size */ + server_data->migration.bytes_transferred = 0; break; case VFU_MIGR_STATE_PRE_COPY: - /* TODO must be less than size of data region in migration region */ - server_data->migration.pending_bytes = server_data->bar1_size; + server_data->migration.bytes_transferred = 0; break; case VFU_MIGR_STATE_STOP: /* FIXME should gracefully fail */ - assert(server_data->migration.pending_bytes == 0); + if (server_data->migration.state == VFU_MIGR_STATE_STOP_AND_COPY) { + assert(server_data->migration.bytes_transferred == + server_data->bar1_size + sizeof(time_t)); + } break; case VFU_MIGR_STATE_RESUME: + server_data->migration.bytes_transferred = 0; break; case VFU_MIGR_STATE_RUNNING: + assert(server_data->migration.bytes_transferred == + server_data->bar1_size + sizeof(time_t)); ret = arm_timer(vfu_ctx, server_data->bar0); if (ret < 0) { return ret; @@ -347,125 +348,100 @@ migration_device_state_transition(vfu_ctx_t *vfu_ctx, vfu_migr_state_t state) return 0; } -static uint64_t -migration_get_pending_bytes(vfu_ctx_t *vfu_ctx) -{ - struct server_data *server_data = vfu_get_private(vfu_ctx); - return server_data->migration.pending_bytes; -} - -static int -migration_prepare_data(vfu_ctx_t *vfu_ctx, uint64_t *offset, uint64_t *size) -{ - struct server_data *server_data = vfu_get_private(vfu_ctx); - - *offset = 0; - if (size != NULL) { - *size = server_data->migration.pending_bytes; - } - return 0; -} - static ssize_t -migration_read_data(vfu_ctx_t *vfu_ctx, void *buf, - uint64_t size, uint64_t offset) +migration_read_data(vfu_ctx_t *vfu_ctx, void *buf, uint64_t size) { struct server_data *server_data = vfu_get_private(vfu_ctx); - if (server_data->migration.state != VFU_MIGR_STATE_PRE_COPY && - server_data->migration.state != VFU_MIGR_STATE_STOP_AND_COPY) - { - return size; - } - /* - * For ease of implementation we expect the client to read all migration - * data in one go; partial reads are not supported. This is allowed by VFIO - * however we don't yet support it. Similarly, when resuming, partial - * writes are supported by VFIO, however we don't in this sample. - * * If in pre-copy state we copy BAR1, if in stop-and-copy state we copy * both BAR1 and BAR0. Since we always copy BAR1 in the stop-and-copy state, * copying BAR1 in the pre-copy state is pointless. Fixing this requires * more complex state tracking which exceeds the scope of this sample. */ - if (offset != 0 || size != server_data->migration.pending_bytes) { - errno = EINVAL; - return -1; - } + uint32_t total_to_read = server_data->bar1_size; - memcpy(buf, server_data->bar1, server_data->bar1_size); if (server_data->migration.state == VFU_MIGR_STATE_STOP_AND_COPY) { - memcpy(buf + server_data->bar1_size, &server_data->bar0, - sizeof(server_data->bar0)); + total_to_read += sizeof(server_data->bar0); + } + + if (server_data->migration.bytes_transferred == total_to_read || size == 0) { + vfu_log(vfu_ctx, LOG_DEBUG, "no data left to read"); + return 0; + } + + uint32_t read_start = server_data->migration.bytes_transferred; + uint32_t read_end = MIN(read_start + size, total_to_read); + assert(read_end > read_start); + + uint32_t bytes_read = read_end - read_start; + + uint32_t length_in_bar1 = 0; + uint32_t length_in_bar0 = 0; + + /* read bar1, if any */ + if (read_start < server_data->bar1_size) { + length_in_bar1 = MIN(bytes_read, server_data->bar1_size - read_start); + memcpy(buf, server_data->bar1 + read_start, length_in_bar1); + read_start += length_in_bar1; + } + + /* read bar0, if any */ + if (read_end > server_data->bar1_size) { + length_in_bar0 = read_end - read_start; + read_start -= server_data->bar1_size; + memcpy(buf + length_in_bar1, &server_data->bar0 + read_start, + length_in_bar0); } - server_data->migration.pending_bytes = 0; - return size; + server_data->migration.bytes_transferred += bytes_read; + + return bytes_read; } static ssize_t -migration_write_data(vfu_ctx_t *vfu_ctx, void *data, - uint64_t size, uint64_t offset) +migration_write_data(vfu_ctx_t *vfu_ctx, void *data, uint64_t size) { struct server_data *server_data = vfu_get_private(vfu_ctx); char *buf = data; - int ret; assert(server_data != NULL); assert(data != NULL); - if (offset != 0 || size < server_data->bar1_size) { - vfu_log(vfu_ctx, LOG_DEBUG, "XXX bad migration data write %#llx-%#llx", - (unsigned long long)offset, - (unsigned long long)offset + size - 1); - errno = EINVAL; - return -1; - } + uint32_t total_to_write = server_data->bar1_size + sizeof(server_data->bar0); - memcpy(server_data->bar1, buf, server_data->bar1_size); - buf += server_data->bar1_size; - size -= server_data->bar1_size; - if (size == 0) { + if (server_data->migration.bytes_transferred == total_to_write || size == 0) { return 0; } - if (size != sizeof(server_data->bar0)) { - errno = EINVAL; - return -1; - } - memcpy(&server_data->bar0, buf, sizeof(server_data->bar0)); - ret = bar0_access(vfu_ctx, buf, sizeof(server_data->bar0), 0, true); - assert(ret == (int)size); /* FIXME */ - return 0; -} + uint32_t write_start = server_data->migration.bytes_transferred; + uint32_t write_end = MIN(write_start + size, total_to_write); // exclusive + assert(write_end > write_start); + uint32_t bytes_written = write_end - write_start; -static int -migration_data_written(UNUSED vfu_ctx_t *vfu_ctx, UNUSED uint64_t count) -{ - /* - * We apply migration state directly in the migration_write_data callback, - * so we don't need to do anything here. We would have to apply migration - * state in this callback if the migration region was memory mappable, in - * which case we wouldn't know when the client wrote migration data. - */ + uint32_t length_in_bar1 = 0; + uint32_t length_in_bar0 = 0; - return 0; -} + /* write to bar1, if any */ + if (write_start < server_data->bar1_size) { + length_in_bar1 = MIN(bytes_written, server_data->bar1_size - write_start); + memcpy(server_data->bar1 + write_start, buf, length_in_bar1); + write_start += length_in_bar1; + } -static size_t -nr_pages(size_t size) -{ - return (size / sysconf(_SC_PAGE_SIZE) + - (size % sysconf(_SC_PAGE_SIZE) > 1)); -} + /* write to bar0, if any */ + if (write_end > server_data->bar1_size) { + length_in_bar0 = write_end - write_start; + write_start -= server_data->bar1_size; + memcpy(&server_data->bar0 + write_start, buf + length_in_bar1, + length_in_bar0); + } -static size_t -page_align(size_t size) -{ - return nr_pages(size) * sysconf(_SC_PAGE_SIZE); + server_data->migration.bytes_transferred += bytes_written; + + return bytes_written; } int main(int argc, char *argv[]) @@ -476,7 +452,6 @@ int main(int argc, char *argv[]) int opt; struct sigaction act = {.sa_handler = _sa_handler}; const size_t bar1_size = 0x3000; - size_t migr_regs_size, migr_data_size, migr_size; struct server_data server_data = { .migration = { .state = VFU_MIGR_STATE_RUNNING @@ -488,10 +463,7 @@ int main(int argc, char *argv[]) const vfu_migration_callbacks_t migr_callbacks = { .version = VFU_MIGR_CALLBACKS_VERS, .transition = &migration_device_state_transition, - .get_pending_bytes = &migration_get_pending_bytes, - .prepare_data = &migration_prepare_data, .read_data = &migration_read_data, - .data_written = &migration_data_written, .write_data = &migration_write_data }; @@ -550,9 +522,6 @@ int main(int argc, char *argv[]) * are mappable. The client can still mmap the 2nd page, we can't prohibit * this under Linux. If we really want to prohibit it we have to use * separate files for the same region. - * - * We choose to use a single file which contains both BAR1 and the migration - * registers. They could also be completely different files. */ if ((tmpfd = mkstemp(template)) == -1) { err(EXIT_FAILURE, "failed to create backing file"); @@ -562,16 +531,7 @@ int main(int argc, char *argv[]) server_data.bar1_size = bar1_size; - /* - * The migration registers aren't memory mappable, so in order to make the - * rest of the migration region memory mappable we must effectively reserve - * an entire page. - */ - migr_regs_size = vfu_get_migr_register_area_size(); - migr_data_size = page_align(bar1_size + sizeof(time_t)); - migr_size = migr_regs_size + migr_data_size; - - if (ftruncate(tmpfd, server_data.bar1_size + migr_size) == -1) { + if (ftruncate(tmpfd, server_data.bar1_size) == -1) { err(EXIT_FAILURE, "failed to truncate backing file"); } server_data.bar1 = mmap(NULL, server_data.bar1_size, PROT_READ | PROT_WRITE, @@ -591,29 +551,8 @@ int main(int argc, char *argv[]) err(EXIT_FAILURE, "failed to setup BAR1 region"); } - /* setup migration */ - - struct iovec migr_mmap_areas[] = { - [0] = { - .iov_base = (void *)migr_regs_size, - .iov_len = migr_data_size - }, - }; - - /* - * The migration region comes after bar1 in the backing file, so offset is - * server_data.bar1_size. - */ - ret = vfu_setup_region(vfu_ctx, VFU_PCI_DEV_MIGR_REGION_IDX, migr_size, - NULL, VFU_REGION_FLAG_RW, migr_mmap_areas, - ARRAY_SIZE(migr_mmap_areas), tmpfd, - server_data.bar1_size); - if (ret < 0) { - err(EXIT_FAILURE, "failed to setup migration region"); - } - - ret = vfu_setup_device_migration_callbacks(vfu_ctx, &migr_callbacks, - migr_regs_size); + ret = vfu_setup_device_migration_callbacks(vfu_ctx, &migr_callbacks); + if (ret < 0) { err(EXIT_FAILURE, "failed to setup device migration"); } |