qemu: Introduce inactive PCI device list

pciTrySecondaryBusReset checks if there is active device on the
same bus, however, qemu driver doesn't maintain an effective
list for the inactive devices, and it passes meaningless argument
for parameter "inactiveDevs". e.g. (qemuPrepareHostdevPCIDevices)

if (!(pcidevs = qemuGetPciHostDeviceList(hostdevs, nhostdevs)))
    return -1;

..skipped...

if (pciResetDevice(dev, driver->activePciHostdevs, pcidevs) < 0)
    goto reattachdevs;

NB, the "pcidevs" used above are extracted from domain def, and
thus one won't be able to attach a device of which bus has other
device even detached from host (nodedev-detach). To see more
details of the problem:

RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=773667

This patch is to resolve the problem by introducing an inactive
PCI device list (just like qemu_driver->activePciHostdevs), and
the whole logic is:

  * Add the device to inactive list during nodedev-dettach
  * Remove the device from inactive list during nodedev-reattach
  * Remove the device from inactive list during attach-device
    (for non-managed device)
  * Add the device to inactive list after detach-device, only
    if the device is not managed

With the above, we have a sufficient inactive PCI device list, and thus
we can use it for pciResetDevice. e.g.(qemuPrepareHostdevPCIDevices)

if (pciResetDevice(dev, driver->activePciHostdevs,
                   driver->inactivePciHostdevs) < 0)
    goto reattachdevs;

src/qemu/qemu_conf.h

@@ -1,7 +1,7 @@
 /*
  * qemu_conf.h: QEMU configuration management
  *
- * Copyright (C) 2006-2007, 2009-2011 Red Hat, Inc.
+ * Copyright (C) 2006-2007, 2009-2012 Red Hat, Inc.
  * Copyright (C) 2006 Daniel P. Berrange
  *
  * This library is free software; you can redistribute it and/or
@@ -128,6 +128,9 @@ struct qemud_driver {
     pciDeviceList *activePciHostdevs;
     usbDeviceList *activeUsbHostdevs;
 
+    /* The devices which is are not in use by the host or any guest. */
+    pciDeviceList *inactivePciHostdevs;
+
     virBitmapPtr reservedVNCPorts;
 
     virSysinfoDefPtr hostsysinfo;

src/qemu/qemu_driver.c

@@ -588,6 +588,9 @@ qemudStartup(int privileged) {
     if ((qemu_driver->activeUsbHostdevs = usbDeviceListNew()) == NULL)
         goto error;
 
+    if ((qemu_driver->inactivePciHostdevs = pciDeviceListNew()) == NULL)
+        goto error;
+
     if (privileged) {
         if (chown(qemu_driver->libDir, qemu_driver->user, qemu_driver->group) < 0) {
             virReportSystemError(errno,
@@ -778,6 +781,7 @@ qemudShutdown(void) {
 
     qemuDriverLock(qemu_driver);
     pciDeviceListFree(qemu_driver->activePciHostdevs);
+    pciDeviceListFree(qemu_driver->inactivePciHostdevs);
     usbDeviceListFree(qemu_driver->activeUsbHostdevs);
     virCapabilitiesFree(qemu_driver->caps);
 
@@ -9211,6 +9215,7 @@ qemudNodeDeviceDettach (virNodeDevicePtr dev)
     pciDevice *pci;
     unsigned domain, bus, slot, function;
     int ret = -1;
+    bool in_inactive_list = false;
 
     if (qemudNodeDeviceGetPciInfo(dev, &domain, &bus, &slot, &function) < 0)
         return -1;
@@ -9220,13 +9225,17 @@ qemudNodeDeviceDettach (virNodeDevicePtr dev)
         return -1;
 
     qemuDriverLock(driver);
-    if (pciDettachDevice(pci, driver->activePciHostdevs) < 0)
+    in_inactive_list = pciDeviceListFind(driver->inactivePciHostdevs, pci);
+
+    if (pciDettachDevice(pci, driver->activePciHostdevs,
+                         driver->inactivePciHostdevs) < 0)
         goto out;
 
     ret = 0;
 out:
     qemuDriverUnlock(driver);
-    pciFreeDevice(pci);
+    if (in_inactive_list)
+        pciFreeDevice(pci);
     return ret;
 }
 
@@ -9248,7 +9257,8 @@ qemudNodeDeviceReAttach (virNodeDevicePtr dev)
     pciDeviceReAttachInit(pci);
 
     qemuDriverLock(driver);
-    if (pciReAttachDevice(pci, driver->activePciHostdevs) < 0)
+    if (pciReAttachDevice(pci, driver->activePciHostdevs,
+                          driver->inactivePciHostdevs) < 0)
         goto out;
 
     ret = 0;
@@ -9275,7 +9285,8 @@ qemudNodeDeviceReset (virNodeDevicePtr dev)
 
     qemuDriverLock(driver);
 
-    if (pciResetDevice(pci, driver->activePciHostdevs, NULL) < 0)
+    if (pciResetDevice(pci, driver->activePciHostdevs,
+                       driver->inactivePciHostdevs) < 0)
         goto out;
 
     ret = 0;

src/qemu/qemu_hostdev.c

@@ -1,7 +1,7 @@
 /*
  * qemu_hostdev.c: QEMU hostdev management
  *
- * Copyright (C) 2006-2007, 2009-2011 Red Hat, Inc.
+ * Copyright (C) 2006-2007, 2009-2012 Red Hat, Inc.
  * Copyright (C) 2006 Daniel P. Berrange
  *
  * This library is free software; you can redistribute it and/or
@@ -212,7 +212,7 @@ int qemuPrepareHostdevPCIDevices(struct qemud_driver *driver,
     for (i = 0; i < pciDeviceListCount(pcidevs); i++) {
         pciDevice *dev = pciDeviceListGet(pcidevs, i);
         if (pciDeviceGetManaged(dev) &&
-            pciDettachDevice(dev, driver->activePciHostdevs) < 0)
+            pciDettachDevice(dev, driver->activePciHostdevs, NULL) < 0)
             goto reattachdevs;
     }
 
@@ -220,7 +220,8 @@ int qemuPrepareHostdevPCIDevices(struct qemud_driver *driver,
      * can safely reset them */
     for (i = 0; i < pciDeviceListCount(pcidevs); i++) {
         pciDevice *dev = pciDeviceListGet(pcidevs, i);
-        if (pciResetDevice(dev, driver->activePciHostdevs, pcidevs) < 0)
+        if (pciResetDevice(dev, driver->activePciHostdevs,
+                           driver->inactivePciHostdevs) < 0)
             goto reattachdevs;
     }
 
@@ -233,7 +234,13 @@ int qemuPrepareHostdevPCIDevices(struct qemud_driver *driver,
         }
     }
 
-    /* Loop 5: Now set the used_by_domain of the device in
+    /* Loop 5: Now remove the devices from inactive list. */
+    for (i = 0; i < pciDeviceListCount(pcidevs); i++) {
+         pciDevice *dev = pciDeviceListGet(pcidevs, i);
+         pciDeviceListDel(driver->inactivePciHostdevs, dev);
+    }
+
+    /* Loop 6: Now set the used_by_domain of the device in
      * driver->activePciHostdevs as domain name.
      */
     for (i = 0; i < pciDeviceListCount(pcidevs); i++) {
@@ -245,7 +252,7 @@ int qemuPrepareHostdevPCIDevices(struct qemud_driver *driver,
         pciDeviceSetUsedBy(activeDev, name);
     }
 
-    /* Loop 6: Now set the original states for hostdev def */
+    /* Loop 7: Now set the original states for hostdev def */
     for (i = 0; i < nhostdevs; i++) {
         pciDevice *dev;
         pciDevice *pcidev;
@@ -277,7 +284,7 @@ int qemuPrepareHostdevPCIDevices(struct qemud_driver *driver,
         pciFreeDevice(dev);
     }
 
-    /* Loop 7: Now steal all the devices from pcidevs */
+    /* Loop 8: Now steal all the devices from pcidevs */
     while (pciDeviceListCount(pcidevs) > 0) {
         pciDevice *dev = pciDeviceListGet(pcidevs, 0);
         pciDeviceListSteal(pcidevs, dev);
@@ -298,7 +305,7 @@ inactivedevs:
 reattachdevs:
     for (i = 0; i < pciDeviceListCount(pcidevs); i++) {
         pciDevice *dev = pciDeviceListGet(pcidevs, i);
-        pciReAttachDevice(dev, driver->activePciHostdevs);
+        pciReAttachDevice(dev, driver->activePciHostdevs, NULL);
     }
 
 cleanup:
@@ -445,8 +452,13 @@ void qemuReattachPciDevice(pciDevice *dev, struct qemud_driver *driver)
 {
     int retries = 100;
 
-    if (!pciDeviceGetManaged(dev))
+    /* If the device is not managed and was attached to guest
+     * successfully, it must have been inactive.
+     */
+    if (!pciDeviceGetManaged(dev)) {
+        pciDeviceListAdd(driver->inactivePciHostdevs, dev);
         return;
+    }
 
     while (pciWaitForDeviceCleanup(dev, "kvm_assigned_device")
            && retries) {
@@ -454,7 +466,8 @@ void qemuReattachPciDevice(pciDevice *dev, struct qemud_driver *driver)
         retries--;
     }
 
-    if (pciReAttachDevice(dev, driver->activePciHostdevs) < 0) {
+    if (pciReAttachDevice(dev, driver->activePciHostdevs,
+                          driver->inactivePciHostdevs) < 0) {
         virErrorPtr err = virGetLastError();
         VIR_ERROR(_("Failed to re-attach PCI device: %s"),
                   err ? err->message : _("unknown error"));
@@ -503,7 +516,8 @@ void qemuDomainReAttachHostdevDevices(struct qemud_driver *driver,
 
     for (i = 0; i < pciDeviceListCount(pcidevs); i++) {
         pciDevice *dev = pciDeviceListGet(pcidevs, i);
-        if (pciResetDevice(dev, driver->activePciHostdevs, pcidevs) < 0) {
+        if (pciResetDevice(dev, driver->activePciHostdevs,
+                           driver->inactivePciHostdevs) < 0) {
             virErrorPtr err = virGetLastError();
             VIR_ERROR(_("Failed to reset PCI device: %s"),
                       err ? err->message : _("unknown error"));

src/qemu/qemu_hotplug.c

@@ -2029,7 +2029,8 @@ qemuDomainDetachHostPciDevice(struct qemud_driver *driver,
                        detach->source.subsys.u.pci.function);
     if (pci) {
         activePci = pciDeviceListSteal(driver->activePciHostdevs, pci);
-        if (pciResetDevice(activePci, driver->activePciHostdevs, NULL))
+        if (pciResetDevice(activePci, driver->activePciHostdevs,
+                           driver->inactivePciHostdevs) == 0)
             qemuReattachPciDevice(activePci, driver);
         else
             ret = -1;

src/util/pci.c

@@ -1117,7 +1117,9 @@ cleanup:
 }
 
 int
-pciDettachDevice(pciDevice *dev, pciDeviceList *activeDevs)
+pciDettachDevice(pciDevice *dev,
+                 pciDeviceList *activeDevs,
+                 pciDeviceList *inactiveDevs)
 {
     const char *driver = pciFindStubDriver();
     if (!driver) {
@@ -1132,11 +1134,22 @@ pciDettachDevice(pciDevice *dev, pciDeviceList *activeDevs)
         return -1;
     }
 
-    return pciBindDeviceToStub(dev, driver);
+    if (pciBindDeviceToStub(dev, driver) < 0)
+        return -1;
+
+    /* Add the dev into list inactiveDevs */
+    if (inactiveDevs && !pciDeviceListFind(inactiveDevs, dev)) {
+        if (pciDeviceListAdd(inactiveDevs, dev) < 0)
+            return -1;
+    }
+
+    return 0;
 }
 
 int
-pciReAttachDevice(pciDevice *dev, pciDeviceList *activeDevs)
+pciReAttachDevice(pciDevice *dev,
+                  pciDeviceList *activeDevs,
+                  pciDeviceList *inactiveDevs)
 {
     const char *driver = pciFindStubDriver();
     if (!driver) {
@@ -1151,7 +1164,14 @@ pciReAttachDevice(pciDevice *dev, pciDeviceList *activeDevs)
         return -1;
     }
 
-    return pciUnbindDeviceFromStub(dev, driver);
+    if (pciUnbindDeviceFromStub(dev, driver) < 0)
+        return -1;
+
+    /* Steal the dev from list inactiveDevs */
+    if (inactiveDevs)
+        pciDeviceListSteal(inactiveDevs, dev);
+
+    return 0;
 }
 
 /* Certain hypervisors (like qemu/kvm) map the PCI bar(s) on

src/util/pci.h

@@ -40,8 +40,12 @@ pciDevice *pciGetDevice      (unsigned       domain,
                               unsigned       function);
 void       pciFreeDevice     (pciDevice     *dev);
 const char *pciDeviceGetName (pciDevice     *dev);
-int        pciDettachDevice  (pciDevice     *dev, pciDeviceList *activeDevs);
+int        pciDettachDevice  (pciDevice     *dev,
-int        pciReAttachDevice (pciDevice     *dev, pciDeviceList *activeDevs);
+                              pciDeviceList *activeDevs,
+                              pciDeviceList *inactiveDevs);
+int        pciReAttachDevice (pciDevice     *dev,
+                              pciDeviceList *activeDevs,
+                              pciDeviceList *inactiveDevs);
 int        pciResetDevice    (pciDevice     *dev,
                               pciDeviceList *activeDevs,
                               pciDeviceList *inactiveDevs);

src/xen/xen_driver.c

@@ -1985,7 +1985,7 @@ xenUnifiedNodeDeviceDettach (virNodeDevicePtr dev)
     if (!pci)
         return -1;
 
-    if (pciDettachDevice(pci, NULL) < 0)
+    if (pciDettachDevice(pci, NULL, NULL) < 0)
         goto out;
 
     ret = 0;
@@ -2075,7 +2075,7 @@ xenUnifiedNodeDeviceReAttach (virNodeDevicePtr dev)
         goto out;
     }
 
-    if (pciReAttachDevice(pci, NULL) < 0)
+    if (pciReAttachDevice(pci, NULL, NULL) < 0)
         goto out;
 
     ret = 0;