1 files changed, 19 insertions, 1 deletions

diff --git a/hw/usb/hcd-ehci-pci.c b/hw/usb/hcd-ehci-pci.c
index d5c7d462d0..5887eab197 100644
--- a/hw/usb/hcd-ehci-pci.c
+++ b/hw/usb/hcd-ehci-pci.c
@@ -17,6 +17,7 @@
 
 #include "hw/usb/hcd-ehci.h"
 #include "hw/pci.h"
+#include "range.h"
 
 typedef struct EHCIPCIState {
     PCIDevice pcidev;
@@ -79,6 +80,21 @@ static int usb_ehci_pci_initfn(PCIDevice *dev)
     return 0;
 }
 
+static void usb_ehci_pci_write_config(PCIDevice *dev, uint32_t addr,
+                                      uint32_t val, int l)
+{
+    EHCIPCIState *i = DO_UPCAST(EHCIPCIState, pcidev, dev);
+    bool busmaster;
+
+    pci_default_write_config(dev, addr, val, l);
+
+    if (!range_covers_byte(addr, l, PCI_COMMAND)) {
+        return;
+    }
+    busmaster = pci_get_word(dev->config + PCI_COMMAND) & PCI_COMMAND_MASTER;
+    i->ehci.dma = busmaster ? pci_dma_context(dev) : NULL;
+}
+
 static Property ehci_pci_properties[] = {
     DEFINE_PROP_UINT32("maxframes", EHCIPCIState, ehci.maxframes, 128),
     DEFINE_PROP_END_OF_LIST(),
@@ -91,6 +107,7 @@ static const VMStateDescription vmstate_ehci_pci = {
     .fields      = (VMStateField[]) {
         VMSTATE_PCI_DEVICE(pcidev, EHCIPCIState),
         VMSTATE_STRUCT(ehci, EHCIPCIState, 2, vmstate_ehci, EHCIState),
+        VMSTATE_END_OF_LIST()
     }
 };
 
@@ -105,7 +122,8 @@ static void ehci_class_init(ObjectClass *klass, void *data)
     k->device_id = i->device_id;
     k->revision = i->revision;
     k->class_id = PCI_CLASS_SERIAL_USB;
-    dc->vmsd = &vmstate_ehci;
+    k->config_write = usb_ehci_pci_write_config;
+    dc->vmsd = &vmstate_ehci_pci;
     dc->props = ehci_pci_properties;
 }