[Qemu-devel] [PATCH] device-assignment: register a reset function

[Bernhard Kohl]

This is necessary because during reboot of a VM the assigned devices
continue DMA transfers which causes memory corruption.

Signed-off-by: Thomas Ostler <address@hidden>
Signed-off-by: Bernhard Kohl <address@hidden>
---
Sorry for for the long delay. Finally we added Alex' suggestions
and rebased the patch.

Thanks
Bernhard
---
 hw/device-assignment.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/hw/device-assignment.c b/hw/device-assignment.c
index 5f5bde1..3f8de66 100644
--- a/hw/device-assignment.c
+++ b/hw/device-assignment.c
@@ -1434,6 +1434,17 @@ static void 
assigned_dev_unregister_msix_mmio(AssignedDevice *dev)
     dev->msix_table_page = NULL;
 }
 
+static void reset_assigned_device(DeviceState *dev)
+{
+    PCIDevice *d = DO_UPCAST(PCIDevice, qdev, dev);
+    uint32_t conf;
+
+    /* reset the bus master bit to avoid further DMA transfers */
+    conf = assigned_dev_pci_read_config(d, PCI_COMMAND, 2);
+    conf &= ~PCI_COMMAND_MASTER;
+    assigned_dev_pci_write_config(d, PCI_COMMAND, conf, 2);
+}
+
 static int assigned_initfn(struct PCIDevice *pci_dev)
 {
     AssignedDevice *dev = DO_UPCAST(AssignedDevice, dev, pci_dev);
@@ -1544,6 +1555,7 @@ static PCIDeviceInfo assign_info = {
     .qdev.name    = "pci-assign",
     .qdev.desc    = "pass through host pci devices to the guest",
     .qdev.size    = sizeof(AssignedDevice),
+    .qdev.reset   = reset_assigned_device,
     .init         = assigned_initfn,
     .exit         = assigned_exitfn,
     .config_read  = assigned_dev_pci_read_config,
-- 
1.7.2.3