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hostdev: Streamline device ownership tracking

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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.
This commit is contained in:
Andrea Bolognani 2016-03-18 18:03:50 +01:00
parent 6da6bf2f30
commit 811286090f
1 changed files with 74 additions and 60 deletions
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134
src/util/virhostdev.c
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@ -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 */
for (i = 0; i < virPCIDeviceListCount(pcidevs); i++) {
virPCIDevicePtr pci = virPCIDeviceListGet(pcidevs, i);
VIR_DEBUG("Adding PCI device %s to active list",
virPCIDeviceGetName(pci));
if (virPCIDeviceListAdd(mgr->activePCIHostdevs, pci) < 0)
goto inactivedevs;
}
/* Step 6: Now remove the devices from inactive list. */
/* 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("Removing PCI device %s from inactive list",
virPCIDeviceGetName(pci));
virPCIDeviceListDel(mgr->inactivePCIHostdevs, pci);
actual = virPCIDeviceListSteal(mgr->inactivePCIHostdevs, pci);
VIR_DEBUG("Adding PCI device %s to active list",
virPCIDeviceGetName(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;
}
VIR_DEBUG("Removing PCI device %s from active list",
virPCIDeviceGetName(pci));
virPCIDeviceListDel(mgr->activePCIHostdevs, pci);
i++;
}
/* At this point, any device that had been used by the guest is in
* pcidevs, but has been removed from activePCIHostdevs.
*/
/* 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;
/* Step 2: restore original network config of hostdevs that used
VIR_DEBUG("Removing PCI device %s from active list",
virPCIDeviceGetName(pci));
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 the inactive list"),
err ? err->message : _("unknown error"));
virResetError(err);
}
}
/* At this point, any device that had been used by the guest has been
* moved to the inactive list */
/* 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);
}