This is necessary because during reboot of a VM the assigned devices
continue DMA transfers which causes memory corruption.
Signed-off-by: Thomas Ostler <thomas.ostler@xxxxxxx>
Signed-off-by: Bernhard Kohl <bernhard.kohl@xxxxxxx>
---
Changes v1 -> v2:
- use defined macros, e.g. PCI_COMMAND
- write all zero to the command register to disconnect the device logically
---
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..8d5a609 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);
+
+ /*
+ * When a 0 is written to the command register, the device is logically
+ * disconnected from the PCI bus. This avoids further DMA transfers.
+ */
+ assigned_dev_pci_write_config(d, PCI_COMMAND, 0, 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
--
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