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[1/3] ide: don't lose pending dma state

Message ID 1459521130-3792-2-git-send-email-den@openvz.org (mailing list archive)
State New, archived
Headers show

Commit Message

Denis V. Lunev April 1, 2016, 2:32 p.m. UTC 
From: Pavel Butsykin <pbutsykin@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(); howeover since DMAING is clear the state upon restore will be
exactly "ready for DMA" as before the save.

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>
---
 hw/ide/core.c     |  9 +--------
 hw/ide/internal.h | 15 +++++++++++++++
 hw/ide/pci.c      |  4 ++++
 3 files changed, 20 insertions(+), 8 deletions(-)
diff mbox

Patch

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;