From 5f81724d80a1492c73d329242663962139db739b Mon Sep 17 00:00:00 2001 From: Peter Lieven Date: Tue, 17 Nov 2015 14:59:52 -0500 Subject: ide/atapi: make PIO read requests async PIO read requests on the ATAPI interface used to be sync blk requests. This has two significant drawbacks. First the main loop hangs util an I/O request is completed and secondly if the I/O request does not complete (e.g. due to an unresponsive storage) Qemu hangs completely. Note: Due to possible race conditions requests during an ongoing elementary transfer are still sync. Signed-off-by: Peter Lieven Reviewed-by: John Snow Message-id: 1447345846-15624-2-git-send-email-pl@kamp.de Signed-off-by: John Snow --- hw/ide/atapi.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 82 insertions(+), 13 deletions(-) diff --git a/hw/ide/atapi.c b/hw/ide/atapi.c index ed8bb2c80a..eb0d964215 100644 --- a/hw/ide/atapi.c +++ b/hw/ide/atapi.c @@ -105,20 +105,27 @@ static void cd_data_to_raw(uint8_t *buf, int lba) memset(buf, 0, 288); } -static int cd_read_sector(IDEState *s, int lba, uint8_t *buf, int sector_size) +static int +cd_read_sector_sync(IDEState *s) { int ret; block_acct_start(blk_get_stats(s->blk), &s->acct, 4 * BDRV_SECTOR_SIZE, BLOCK_ACCT_READ); - switch(sector_size) { +#ifdef DEBUG_IDE_ATAPI + printf("cd_read_sector_sync: lba=%d\n", s->lba); +#endif + + switch (s->cd_sector_size) { case 2048: - ret = blk_read(s->blk, (int64_t)lba << 2, buf, 4); + ret = blk_read(s->blk, (int64_t)s->lba << 2, + s->io_buffer, 4); break; case 2352: - ret = blk_read(s->blk, (int64_t)lba << 2, buf + 16, 4); + ret = blk_read(s->blk, (int64_t)s->lba << 2, + s->io_buffer + 16, 4); if (ret >= 0) { - cd_data_to_raw(buf, lba); + cd_data_to_raw(s->io_buffer, s->lba); } break; default: @@ -130,11 +137,65 @@ static int cd_read_sector(IDEState *s, int lba, uint8_t *buf, int sector_size) block_acct_failed(blk_get_stats(s->blk), &s->acct); } else { block_acct_done(blk_get_stats(s->blk), &s->acct); + s->lba++; + s->io_buffer_index = 0; } return ret; } +static void cd_read_sector_cb(void *opaque, int ret) +{ + IDEState *s = opaque; + + block_acct_done(blk_get_stats(s->blk), &s->acct); + +#ifdef DEBUG_IDE_ATAPI + printf("cd_read_sector_cb: lba=%d ret=%d\n", s->lba, ret); +#endif + + if (ret < 0) { + ide_atapi_io_error(s, ret); + return; + } + + if (s->cd_sector_size == 2352) { + cd_data_to_raw(s->io_buffer, s->lba); + } + + s->lba++; + s->io_buffer_index = 0; + s->status &= ~BUSY_STAT; + + ide_atapi_cmd_reply_end(s); +} + +static int cd_read_sector(IDEState *s) +{ + if (s->cd_sector_size != 2048 && s->cd_sector_size != 2352) { + return -EINVAL; + } + + s->iov.iov_base = (s->cd_sector_size == 2352) ? + s->io_buffer + 16 : s->io_buffer; + + s->iov.iov_len = 4 * BDRV_SECTOR_SIZE; + qemu_iovec_init_external(&s->qiov, &s->iov, 1); + +#ifdef DEBUG_IDE_ATAPI + printf("cd_read_sector: lba=%d\n", s->lba); +#endif + + block_acct_start(blk_get_stats(s->blk), &s->acct, + 4 * BDRV_SECTOR_SIZE, BLOCK_ACCT_READ); + + blk_aio_readv(s->blk, (int64_t)s->lba << 2, &s->qiov, 4, + cd_read_sector_cb, s); + + s->status |= BUSY_STAT; + return 0; +} + void ide_atapi_cmd_ok(IDEState *s) { s->error = 0; @@ -196,18 +257,27 @@ void ide_atapi_cmd_reply_end(IDEState *s) ide_atapi_cmd_ok(s); ide_set_irq(s->bus); #ifdef DEBUG_IDE_ATAPI - printf("status=0x%x\n", s->status); + printf("end of transfer, status=0x%x\n", s->status); #endif } else { /* see if a new sector must be read */ if (s->lba != -1 && s->io_buffer_index >= s->cd_sector_size) { - ret = cd_read_sector(s, s->lba, s->io_buffer, s->cd_sector_size); - if (ret < 0) { - ide_atapi_io_error(s, ret); + if (!s->elementary_transfer_size) { + ret = cd_read_sector(s); + if (ret < 0) { + ide_atapi_io_error(s, ret); + } return; + } else { + /* rebuffering within an elementary transfer is + * only possible with a sync request because we + * end up with a race condition otherwise */ + ret = cd_read_sector_sync(s); + if (ret < 0) { + ide_atapi_io_error(s, ret); + return; + } } - s->lba++; - s->io_buffer_index = 0; } if (s->elementary_transfer_size > 0) { /* there are some data left to transmit in this elementary @@ -287,7 +357,6 @@ static void ide_atapi_cmd_read_pio(IDEState *s, int lba, int nb_sectors, s->io_buffer_index = sector_size; s->cd_sector_size = sector_size; - s->status = READY_STAT | SEEK_STAT; ide_atapi_cmd_reply_end(s); } @@ -372,7 +441,7 @@ eot: if (ret < 0) { block_acct_failed(blk_get_stats(s->blk), &s->acct); } else { - block_acct_done(blk_get_stats(s->blk), &s->acct); + block_acct_done(blk_get_stats(s->blk), &s->acct); } ide_set_inactive(s, false); } -- cgit v1.2.3