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authorPavel Butsykin <pbutsykin@virtuozzo.com>2016-04-12 16:47:52 -0400
committerJohn Snow <jsnow@redhat.com>2016-04-12 16:47:52 -0400
commit9a41826f3843bf11bf8f52f176071f8c1fb0aa7e (patch)
treee6412f738c4297dacc560dd55046f2485ae6b1a8 /hw/ide/atapi.c
parent218fd37c68e450dffe37832e82a1f0a6592e7169 (diff)
ide: restart atapi dma by re-evaluating command packet
ide_atapi_dma_restart() used to just complete the DMA with an error, under the assumption that there isn't enough information to restart it. However, as the contents of the ->io_buffer is preserved, it looks safe to just re-evaluate it and dispatch the ATAPI command again. Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com> Reviewed-by: Roman Kagan <rkagan@virtuozzo.com> Signed-off-by: Denis V. Lunev <den@openvz.org> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 1459924806-306-3-git-send-email-den@openvz.org Signed-off-by: John Snow <jsnow@redhat.com>
Diffstat (limited to 'hw/ide/atapi.c')
-rw-r--r--hw/ide/atapi.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/hw/ide/atapi.c b/hw/ide/atapi.c
index 1fe58ab7fd..acc52cd11f 100644
--- a/hw/ide/atapi.c
+++ b/hw/ide/atapi.c
@@ -488,14 +488,13 @@ static void ide_atapi_cmd_read(IDEState *s, int lba, int nb_sectors,
void ide_atapi_dma_restart(IDEState *s)
{
/*
- * I'm not sure we have enough stored to restart the command
- * safely, so give the guest an error it should recover from.
- * I'm assuming most guests will try to recover from something
- * listed as a medium error on a CD; it seems to work on Linux.
- * This would be more of a problem if we did any other type of
- * DMA operation.
+ * At this point we can just re-evaluate the packet command and start over.
+ * The presence of ->dma_cb callback in the pre_save ensures that the packet
+ * command has been completely sent and we can safely restart command.
*/
- ide_atapi_cmd_error(s, MEDIUM_ERROR, ASC_NO_SEEK_COMPLETE);
+ s->unit = s->bus->retry_unit;
+ s->bus->dma->ops->restart_dma(s->bus->dma);
+ ide_atapi_cmd(s);
}
static inline uint8_t ide_atapi_set_profile(uint8_t *buf, uint8_t *index,