On 03/28/2016 07:48 AM, Denis V. Lunev wrote:
> From: Pavel Butsykin <pbutsy...@virtuozzo.com>
>
> If the migration occurs after the IDE DMA has been set up but before it
> has been initiated, the state gets lost upon save/restore. Specifically,
> ->dma_cb callback gets cleared, so, when the guest eventually starts bus
> mastering, the DMA never completes, causing the guest to time out the
> operation.
>
> OTOH all the infrastructure is already in place to restart the DMA if
> the migration happens while the DMA is in progress.
>
> So reuse that infrastructure, by setting bus->error_status based on
> ->dma_cmd in pre_save if ->dma_cb callback is already set but DMAING is
> clear. This will indicate the need for restart and make sure ->dma_cb is
> restored in ide_restart_bh(); however since DMAING is clear the state
> upon restore will be exactly "ready for DMA" as before the save.
>
> Signed-off-by: Pavel Butsykin <pbutsy...@virtuozzo.com>
> Reviewed-by: Roman Kagan <rka...@virtuozzo.com>
> Signed-off-by: Denis V. Lunev <d...@openvz.org>
> CC: John Snow <js...@redhat.com>
> ---
> hw/ide/core.c | 9 +--------
> hw/ide/internal.h | 15 +++++++++++++++
> hw/ide/pci.c | 4 ++++
> 3 files changed, 20 insertions(+), 8 deletions(-)
>
> diff --git a/hw/ide/core.c b/hw/ide/core.c
> index 241e840..8f86036 100644
> --- a/hw/ide/core.c
> +++ b/hw/ide/core.c
> @@ -803,14 +803,7 @@ static void ide_dma_cb(void *opaque, int ret)
> return;
> }
> if (ret < 0) {
> - int op = IDE_RETRY_DMA;
> -
> - if (s->dma_cmd == IDE_DMA_READ)
> - op |= IDE_RETRY_READ;
> - else if (s->dma_cmd == IDE_DMA_TRIM)
> - op |= IDE_RETRY_TRIM;
> -
> - if (ide_handle_rw_error(s, -ret, op)) {
> + if (ide_handle_rw_error(s, -ret, ide_dma_cmd_to_retry(s->dma_cmd))) {
> return;
> }
> }
> diff --git a/hw/ide/internal.h b/hw/ide/internal.h
> index 86bde26..68c7d0d 100644
> --- a/hw/ide/internal.h
> +++ b/hw/ide/internal.h
> @@ -513,6 +513,21 @@ struct IDEDevice {
> #define IDE_RETRY_TRIM 0x80
> #define IDE_RETRY_HBA 0x100
>
> +static inline uint8_t ide_dma_cmd_to_retry(uint8_t dma_cmd)
> +{
> + switch (dma_cmd) {
> + case IDE_DMA_READ:
> + return IDE_RETRY_DMA | IDE_RETRY_READ;
> + case IDE_DMA_WRITE:
> + return IDE_RETRY_DMA;
> + case IDE_DMA_TRIM:
> + return IDE_RETRY_DMA | IDE_RETRY_TRIM;
> + default:
> + break;
> + }
> + return 0;
> +}
> +
> static inline IDEState *idebus_active_if(IDEBus *bus)
> {
> return bus->ifs + bus->unit;
> diff --git a/hw/ide/pci.c b/hw/ide/pci.c
> index 92ffee7..8d56a00 100644
> --- a/hw/ide/pci.c
> +++ b/hw/ide/pci.c
> @@ -308,6 +308,10 @@ static void ide_bmdma_pre_save(void *opaque)
> BMDMAState *bm = opaque;
> uint8_t abused_bits = BM_MIGRATION_COMPAT_STATUS_BITS;
>
> + if (!(bm->status & BM_STATUS_DMAING) && bm->dma_cb) {
> + bm->bus->error_status =
> + ide_dma_cmd_to_retry(bmdma_active_if(bm)->dma_cmd);
> + }
> bm->migration_retry_unit = bm->bus->retry_unit;
> bm->migration_retry_sector_num = bm->bus->retry_sector_num;
> bm->migration_retry_nsector = bm->bus->retry_nsector;
>
_this_ is the one I meant to R-B, thanks Denis. (Testing the others now,
but having some laptop issues. Please stand by.)
Reviewed-by: John Snow <js...@redhat.com>
