workaround for cmd646 bmdma register access while no dma is active

This is a workaround only, and is a partial revert
of a few changes to BMDMAState which removed pci_dev
field on the way.

- cmd646 pci_from_bm() expects bm->unit value to
correspond with bm data being passed to callback
as opaque pointer. This breaks when write to dma
control register of second channel happens when no
dma operation is in progress, so bm->unit is zero
for second channel, and pci_from_bm() returns garbage
pointer. Crash happens shortly after that while
dereferencing that pointer.

v0->v1: cleaned up dead code from pci_from_bm.

Signed-off-by: Igor V. Kovalenko <igor.v.kovalenko@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
(cherry picked from commit 90228ee395b71cdd64e6bc844e3d553eb9ef643f)

diff --git a/hw/ide/cmd646.c b/hw/ide/cmd646.c
index e1e626e2a64eb138b7a8844a7e1b152de5fa99af..835c98d72976844063cb994355e6a894914619e5 100644 (file)
--- a/hw/ide/cmd646.c
+++ b/hw/ide/cmd646.c
@@ -70,11 +70,7 @@ static void ide_map(PCIDevice *pci_dev, int region_num,
 
 static PCIIDEState *pci_from_bm(BMDMAState *bm)
 {
-    if (bm->unit == 0) {
-        return container_of(bm, PCIIDEState, bmdma[0]);
-    } else {
-        return container_of(bm, PCIIDEState, bmdma[1]);
-    }
+    return bm->pci_dev;
 }
 
 static uint32_t bmdma_readb(void *opaque, uint32_t addr)
@@ -145,6 +141,7 @@ static void bmdma_map(PCIDevice *pci_dev, int region_num,
         BMDMAState *bm = &d->bmdma[i];
         d->bus[i].bmdma = bm;
         bm->bus = d->bus+i;
+        bm->pci_dev = d;
         qemu_add_vm_change_state_handler(ide_dma_restart_cb, bm);
 
         register_ioport_write(addr, 1, 1, bmdma_cmd_writeb, bm);

diff --git a/hw/ide/internal.h b/hw/ide/internal.h
index 8869a0834b1d3d9db72973803bbf3ef20600ee20..8615d1a1fa55d8ec1ec4910664b950be7f04902c 100644 (file)
--- a/hw/ide/internal.h
+++ b/hw/ide/internal.h
@@ -481,6 +481,7 @@ struct BMDMAState {
     uint8_t status;
     uint32_t addr;
 
+    struct PCIIDEState *pci_dev;
     IDEBus *bus;
     /* current transfer state */
     uint32_t cur_addr;

diff --git a/hw/ide/piix.c b/hw/ide/piix.c
index de3648023edc72eac2be440ec71f98da8800d37d..2776ac3650a7f7f38aad381c6211c02b136354d5 100644 (file)
--- a/hw/ide/piix.c
+++ b/hw/ide/piix.c
@@ -78,6 +78,7 @@ static void bmdma_map(PCIDevice *pci_dev, int region_num,
         BMDMAState *bm = &d->bmdma[i];
         d->bus[i].bmdma = bm;
         bm->bus = d->bus+i;
+        bm->pci_dev = d;
         qemu_add_vm_change_state_handler(ide_dma_restart_cb, bm);
 
         register_ioport_write(addr, 1, 1, bmdma_cmd_writeb, bm);