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authorPeter Lieven <pl@kamp.de>2015-11-17 14:59:52 -0500
committerJohn Snow <jsnow@redhat.com>2015-11-17 15:06:15 -0500
commit5f81724d80a1492c73d329242663962139db739b (patch)
treea8fbe7169471029e3c4f730336e20414e3b383f1
parentc27e9014d56fa4880e7d741275d887c3a5949997 (diff)
downloadhqemu-5f81724d80a1492c73d329242663962139db739b.zip
hqemu-5f81724d80a1492c73d329242663962139db739b.tar.gz
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 <pl@kamp.de> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 1447345846-15624-2-git-send-email-pl@kamp.de Signed-off-by: John Snow <jsnow@redhat.com>
-rw-r--r--hw/ide/atapi.c95
1 files changed, 82 insertions, 13 deletions
diff --git a/hw/ide/atapi.c b/hw/ide/atapi.c
index ed8bb2c..eb0d964 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);
}
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