pci/pcie: stop plug/unplug if the slot is locked

We better stop right away. For now, errors would be partially ignored
(so the guest might get informed or the device might get unplugged),
although actual plug/unplug will be reported as failed to the user.

While at it, properly move the check to the pre_plug handler for the plug
case, as we can test the slot state before the device will be realized.

Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

2 files changed, 18 insertions, 8 deletions

diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index 2d3d8a047b..230478faab 100644
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -391,10 +391,10 @@ static void pcie_cap_slot_event(PCIDevice *dev, PCIExpressHotPlugEvent event)
 }
 
 static void pcie_cap_slot_plug_common(PCIDevice *hotplug_dev, DeviceState *dev,
-                                      uint8_t **exp_cap, Error **errp)
+                                      Error **errp)
 {
-    *exp_cap = hotplug_dev->config + hotplug_dev->exp.exp_cap;
-    uint16_t sltsta = pci_get_word(*exp_cap + PCI_EXP_SLTSTA);
+    uint8_t *exp_cap = hotplug_dev->config + hotplug_dev->exp.exp_cap;
+    uint16_t sltsta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
 
     PCIE_DEV_PRINTF(PCI_DEVICE(dev), "hotplug state: 0x%x\n", sltsta);
     if (sltsta & PCI_EXP_SLTSTA_EIS) {
@@ -405,14 +405,19 @@ static void pcie_cap_slot_plug_common(PCIDevice *hotplug_dev, DeviceState *dev,
     }
 }
 
+void pcie_cap_slot_pre_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
+                               Error **errp)
+{
+    pcie_cap_slot_plug_common(PCI_DEVICE(hotplug_dev), dev, errp);
+}
+
 void pcie_cap_slot_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
                            Error **errp)
 {
-    uint8_t *exp_cap;
+    PCIDevice *hotplug_pdev = PCI_DEVICE(hotplug_dev);
+    uint8_t *exp_cap = hotplug_pdev->config + hotplug_pdev->exp.exp_cap;
     PCIDevice *pci_dev = PCI_DEVICE(dev);
 
-    pcie_cap_slot_plug_common(PCI_DEVICE(hotplug_dev), dev, &exp_cap, errp);
-
     /* Don't send event when device is enabled during qemu machine creation:
      * it is present on boot, no hotplug event is necessary. We do send an
      * event when the device is disabled later. */
@@ -458,11 +463,15 @@ static void pcie_unplug_device(PCIBus *bus, PCIDevice *dev, void *opaque)
 void pcie_cap_slot_unplug_request_cb(HotplugHandler *hotplug_dev,
                                      DeviceState *dev, Error **errp)
 {
-    uint8_t *exp_cap;
+    Error *local_err = NULL;
     PCIDevice *pci_dev = PCI_DEVICE(dev);
     PCIBus *bus = pci_get_bus(pci_dev);
 
-    pcie_cap_slot_plug_common(PCI_DEVICE(hotplug_dev), dev, &exp_cap, errp);
+    pcie_cap_slot_plug_common(PCI_DEVICE(hotplug_dev), dev, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
 
     /* In case user cancel the operation of multi-function hot-add,
      * remove the function that is unexposed to guest individually,
diff --git a/hw/pci/pcie_port.c b/hw/pci/pcie_port.c
index bc07abc31b..a30291ef54 100644
--- a/hw/pci/pcie_port.c
+++ b/hw/pci/pcie_port.c
@@ -154,6 +154,7 @@ static void pcie_slot_class_init(ObjectClass *oc, void *data)
     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(oc);
 
     dc->props = pcie_slot_props;
+    hc->pre_plug = pcie_cap_slot_pre_plug_cb;
     hc->plug = pcie_cap_slot_plug_cb;
     hc->unplug = pcie_cap_slot_unplug_cb;
     hc->unplug_request = pcie_cap_slot_unplug_request_cb;