[libvirt] [PATCH v2 1/4] hostdev: Streamline device ownership tracking
Andrea Bolognani
abologna at redhat.com
Fri Mar 18 17:03:50 UTC 2016
After this patch, ownership of virPCIDevice instances is very easy
to keep track of: for each host PCI device, the only instance that
actually matters is the one inside one of the bookkeeping list.
Whenever some operation needs to be performed on a PCI device, the
actual device is looked up first; when this is not the case, a
comment explains the reason.
---
src/util/virhostdev.c | 130 ++++++++++++++++++++++++++++----------------------
1 file changed, 72 insertions(+), 58 deletions(-)
diff --git a/src/util/virhostdev.c b/src/util/virhostdev.c
index 572aec0..e8efc53 100644
--- a/src/util/virhostdev.c
+++ b/src/util/virhostdev.c
@@ -527,10 +527,7 @@ virHostdevPreparePCIDevices(virHostdevManagerPtr mgr,
* impacts all devices on it. Also, all devices must be reset
* before being marked as active */
- /* Step 1: validate that non-managed device isn't in use, eg
- * by checking that device is either un-bound, or bound
- * to pci-stub.ko
- */
+ /* Step 1: Perform some initial checks on the devices */
for (i = 0; i < virPCIDeviceListCount(pcidevs); i++) {
virPCIDevicePtr pci = virPCIDeviceListGet(pcidevs, i);
bool strict_acs_check = !!(flags & VIR_HOSTDEV_STRICT_ACS_CHECK);
@@ -659,28 +656,22 @@ virHostdevPreparePCIDevices(virHostdevManagerPtr mgr,
last_processed_hostdev_vf = i;
}
- /* Step 5: Now mark all the devices as active */
+ /* Step 5: Move devices from the inactive list to the active list */
for (i = 0; i < virPCIDeviceListCount(pcidevs); i++) {
virPCIDevicePtr pci = virPCIDeviceListGet(pcidevs, i);
+ virPCIDevicePtr actual;
- VIR_DEBUG("Adding PCI device %s to active list",
+ VIR_DEBUG("Removing PCI device %s from inactive list",
virPCIDeviceGetName(pci));
- if (virPCIDeviceListAdd(mgr->activePCIHostdevs, pci) < 0)
- goto inactivedevs;
- }
-
- /* Step 6: Now remove the devices from inactive list. */
- for (i = 0; i < virPCIDeviceListCount(pcidevs); i++) {
- virPCIDevicePtr pci = virPCIDeviceListGet(pcidevs, i);
+ actual = virPCIDeviceListSteal(mgr->inactivePCIHostdevs, pci);
- VIR_DEBUG("Removing PCI device %s from inactive list",
+ VIR_DEBUG("Adding PCI device %s to active list",
virPCIDeviceGetName(pci));
- virPCIDeviceListDel(mgr->inactivePCIHostdevs, pci);
+ if (!actual || virPCIDeviceListAdd(mgr->activePCIHostdevs, actual) < 0)
+ goto inactivedevs;
}
- /* Step 7: Now set the used_by_domain of the device in
- * activePCIHostdevs as domain name.
- */
+ /* Step 6: Set driver and domain information */
for (i = 0; i < virPCIDeviceListCount(pcidevs); i++) {
virPCIDevicePtr pci, actual;
@@ -696,7 +687,7 @@ virHostdevPreparePCIDevices(virHostdevManagerPtr mgr,
virPCIDeviceSetUsedBy(actual, drv_name, dom_name);
}
- /* Step 8: Now set the original states for hostdev def */
+ /* Step 7: Now set the original states for hostdev def */
for (i = 0; i < nhostdevs; i++) {
virPCIDevicePtr pci;
virDomainHostdevDefPtr hostdev = hostdevs[i];
@@ -728,23 +719,26 @@ virHostdevPreparePCIDevices(virHostdevManagerPtr mgr,
}
}
- /* Step 9: Now steal all the devices from pcidevs */
- while (virPCIDeviceListCount(pcidevs) > 0)
- virPCIDeviceListStealIndex(pcidevs, 0);
-
ret = 0;
goto cleanup;
inactivedevs:
- /* Only steal all the devices from activePCIHostdevs. We will
- * free them in virObjectUnref().
- */
+ /* Move devices back to the inactive list so that they can be
+ * processed properly below (reattachdevs label) */
for (i = 0; i < virPCIDeviceListCount(pcidevs); i++) {
virPCIDevicePtr pci = virPCIDeviceListGet(pcidevs, i);
+ virPCIDevicePtr actual;
VIR_DEBUG("Removing PCI device %s from active list",
virPCIDeviceGetName(pci));
- virPCIDeviceListSteal(mgr->activePCIHostdevs, pci);
+ if (!(actual = virPCIDeviceListSteal(mgr->activePCIHostdevs, pci)))
+ continue;
+
+ VIR_DEBUG("Adding PCI device %s to inactive list",
+ virPCIDeviceGetName(pci));
+ if (virPCIDeviceListAdd(mgr->inactivePCIHostdevs, actual) < 0)
+ VIR_WARN("Failed to add PCI device %s to the inactive list",
+ virPCIDeviceGetName(pci));
}
resetvfnetconfig:
@@ -756,11 +750,17 @@ virHostdevPreparePCIDevices(virHostdevManagerPtr mgr,
reattachdevs:
for (i = 0; i < virPCIDeviceListCount(pcidevs); i++) {
virPCIDevicePtr pci = virPCIDeviceListGet(pcidevs, i);
+ virPCIDevicePtr actual;
- if (virPCIDeviceGetManaged(pci)) {
+ /* We need to look up the actual device because that's what
+ * virPCIDeviceReattach() exepects as its argument */
+ if (!(actual = virPCIDeviceListFind(mgr->inactivePCIHostdevs, pci)))
+ continue;
+
+ if (virPCIDeviceGetManaged(actual)) {
VIR_DEBUG("Reattaching managed PCI device %s",
virPCIDeviceGetName(pci));
- ignore_value(virPCIDeviceReattach(pci,
+ ignore_value(virPCIDeviceReattach(actual,
mgr->activePCIHostdevs,
mgr->inactivePCIHostdevs));
} else {
@@ -785,17 +785,6 @@ static void
virHostdevReattachPCIDevice(virHostdevManagerPtr mgr,
virPCIDevicePtr actual)
{
- /* If the device is not managed and was attached to guest
- * successfully, it must have been inactive.
- */
- if (!virPCIDeviceGetManaged(actual)) {
- VIR_DEBUG("Adding unmanaged PCI device %s to inactive list",
- virPCIDeviceGetName(actual));
- if (virPCIDeviceListAdd(mgr->inactivePCIHostdevs, actual) < 0)
- virPCIDeviceFree(actual);
- return;
- }
-
/* Wait for device cleanup if it is qemu/kvm */
if (virPCIDeviceGetStubDriver(actual) == VIR_PCI_STUB_DRIVER_KVM) {
int retries = 100;
@@ -814,7 +803,6 @@ virHostdevReattachPCIDevice(virHostdevManagerPtr mgr,
err ? err->message : _("unknown error"));
virResetError(err);
}
- virPCIDeviceFree(actual);
}
/* @oldStateDir:
@@ -848,9 +836,8 @@ virHostdevReAttachPCIDevices(virHostdevManagerPtr mgr,
/* Reattaching devices to the host involves several steps; each
* of them is described at length below */
- /* Step 1: verify that each device in the hostdevs list really was in use
- * by this domain, and remove them all from the activePCIHostdevs list.
- */
+ /* Step 1: Filter out all devices that are either not active or not
+ * used by the current domain and driver */
i = 0;
while (i < virPCIDeviceListCount(pcidevs)) {
virPCIDevicePtr pci = virPCIDeviceListGet(pcidevs, i);
@@ -876,17 +863,34 @@ virHostdevReAttachPCIDevices(virHostdevManagerPtr mgr,
continue;
}
+ i++;
+ }
+
+ /* Step 2: Move devices from the active list to the inactive list */
+ for (i = 0; i < virPCIDeviceListCount(pcidevs); i++) {
+ virPCIDevicePtr pci = virPCIDeviceListGet(pcidevs, i);
+ virPCIDevicePtr actual;
+
VIR_DEBUG("Removing PCI device %s from active list",
virPCIDeviceGetName(pci));
- virPCIDeviceListDel(mgr->activePCIHostdevs, pci);
- i++;
+ actual = virPCIDeviceListSteal(mgr->activePCIHostdevs, pci);
+
+ VIR_DEBUG("Adding PCI device %s to inactive list",
+ virPCIDeviceGetName(pci));
+ if (!actual ||
+ virPCIDeviceListAdd(mgr->inactivePCIHostdevs, actual) < 0) {
+
+ virErrorPtr err = virGetLastError();
+ VIR_ERROR(_("Failed to add PCI device %s to inactive list"),
+ err ? err->message : _("unknown error"));
+ virResetError(err);
+ }
}
- /* At this point, any device that had been used by the guest is in
- * pcidevs, but has been removed from activePCIHostdevs.
- */
+ /* At this point, any device that had been used by the guest has been
+ * moved to the inactive list */
- /* Step 2: restore original network config of hostdevs that used
+ /* Step 3: restore original network config of hostdevs that used
* <interface type='hostdev'>
*/
for (i = 0; i < nhostdevs; i++) {
@@ -911,7 +915,7 @@ virHostdevReAttachPCIDevices(virHostdevManagerPtr mgr,
}
}
- /* Step 3: perform a PCI Reset on all devices */
+ /* Step 4: perform a PCI Reset on all devices */
for (i = 0; i < virPCIDeviceListCount(pcidevs); i++) {
virPCIDevicePtr pci = virPCIDeviceListGet(pcidevs, i);
@@ -928,16 +932,26 @@ virHostdevReAttachPCIDevices(virHostdevManagerPtr mgr,
}
}
- /* Step 4: reattach devices to their host drivers (if managed) or place
- * them on the inactive list (if not managed)
- */
- while (virPCIDeviceListCount(pcidevs) > 0) {
- virPCIDevicePtr pci = virPCIDeviceListStealIndex(pcidevs, 0);
- virHostdevReattachPCIDevice(mgr, pci);
+ /* Step 5: Reattach managed devices to their host drivers; unmanaged
+ * devices don't need to be processed further */
+ for (i = 0; i < virPCIDeviceListCount(pcidevs); i++) {
+ virPCIDevicePtr pci = virPCIDeviceListGet(pcidevs, i);
+ virPCIDevicePtr actual;
+
+ /* We need to look up the actual device because that's what
+ * virHostdevReattachPCIDevice() expects as its argument */
+ if (!(actual = virPCIDeviceListFind(mgr->inactivePCIHostdevs, pci)))
+ continue;
+
+ if (virPCIDeviceGetManaged(actual))
+ virHostdevReattachPCIDevice(mgr, actual);
+ else
+ VIR_DEBUG("Not reattaching unmanaged PCI device %s",
+ virPCIDeviceGetName(actual));
}
- virObjectUnref(pcidevs);
cleanup:
+ virObjectUnref(pcidevs);
virObjectUnlock(mgr->activePCIHostdevs);
virObjectUnlock(mgr->inactivePCIHostdevs);
}
--
2.5.0
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