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ide: restart atapi dma by re-evaluating command packet

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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>
This commit is contained in:
Pavel Butsykin 2016-04-12 16:47:52 -04:00 committed by John Snow
parent 218fd37c68
commit 9a41826f38
1 changed files with 6 additions and 7 deletions
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13
hw/ide/atapi.c
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@ -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,