Having this information available will make it easier to determine the
culprit when MAC or vlan tag appear to not be set, eg.:

  https://bugzilla.redhat.com/1364073

(This patch doesn't fix that bug, just makes it easier to diagnose)

If an SRIOV VF has previously been used for VFIO device assignment,
the "admin MAC" that is stored in the PF driver's table of VF info
will have been set to the MAC address that the virtual machine wanted
the device to have. Setting the admin MAC for a VF also sets a flag in
the PF that is loosely called the "administratively set" flag. Once
that flag is set, it is no longer possible for the net driver of the
VF (either on the host or in a virtual machine) to directly set the
VF's MAC again; this flag isn't reset until the *PF* driver is
restarted, and that requires taking *all* VFs offline, so it's not
really feasible to do.

If the same SRIOV VF is later used for macvtap passthrough mode, the
VF's MAC address must be set, but normally we don't unbind the VF from
its host net driver (since we actually need the host net driver in
this case). Since setting the VF MAC directly will fail, in the past
"we" ("I") had tried to fix the problem by simply setting the admin MAC
(via the PF) instead. This *appeared* to work (and might have at one
time, due to promiscuous mode being turned on somewhere or something),
but it currently creates a non-working interface because only the
value for admin MAC is set to the desired value, *not* the actual MAC
that the VF is using.

Earlier patches in this series reverted that behavior, so that we once
again set the MAC of the VF itself for macvtap passthrough operation,
not the admin MAC. But that brings back the original bug - if the
interface has been used for VFIO device assignment, you can no longer
use it for macvtap passthrough.

This patch solves that problem by noticing when virNetDevSetMAC()
fails for a VF, and in that case it sets the desired MAC to the admin
MAC via the PF, then "bounces" the VF driver (by unbinding and the
immediately rebinding it to the VF). This causes the VF's MAC to be
reinitialized from the admin MAC, and everybody is happy (until the
*next* time someone wants to set the VF's MAC address, since the
"administratively set" bit is still turned on).

Some PF drivers allow setting the admin MAC (that is the MAC address
that the VF will be initialized to the next time the VF's driver is
loaded) to 00:00:00:00:00:00, and some don't. Multiple drivers
initialize the admin MACs to all 0, but don't allow setting it to that
very same value. It has been an uphill battle convincing the driver
people that it's reasonable to expect The argument that's used is
that an all 0 device MAC address on a device is invalid; however, from
an outsider's point of view, when the admin MAC is set to 0 at the
time the VF driver is loaded, the VF's MAC is *not* set to 0, but to a
random non-0 value. But that's beside the point - even if I could
convince one or two SRIOV driver maintainers to permit setting the
admin MAC to 0, there are still several other drivers.

So rather than fighting that losing battle, this patch checks for a
failure to set the admin MAC due to an all 0 value, and retries it
with 02:00:00:00:00:00. That won't result in a random value being set
in the VF MAC at next VF driver init, but that's okay, because we
always want to set a specific value anyway. Rather, the "almost 0"
setting makes it easy to visually detect from the output of "ip link
show" which VFs are currently in use and which are free.

The global functions virNetDevReplaceMacAddress(),
virNetDevReplaceNetConfig(), virNetDevRestoreMacAddress(), and
virNetDevRestoreNetConfig() are no longer used, as their functionality
has been replaced by virNetDev(Save|Read|Set)NetConfig().

The static functions virNetDevReplaceVfConfig() and
virNetDevRestoreVfConfig() were only used by the above-named global
functions that were removed.

It takes longer to explain this than to fix it...

In the past we weren't able to save the VF's own MAC address *at all*
when using it for hostdev assignment, because we had already unbound
the VF from the host net driver prior to saving its config. With the
previous patch, that problem has been solved, so we now have the VF's
MAC address saved and can move on to the *next* problem, which is twofold:

1) during teardown we restore the config before we've re-bound, so the
   VF doesn't have a net driver, and thus we can't set its MAC address
   directly.

2) even if we delay restoring the config until the VF is bound to a
   net driver, the request to set its MAC address would fail, since
   (during device setup) we had set the "admin MAC" for the VF via an
   RTM_SETLINK to the PF - once you've set the admin MAC for a VF, the
   VF driver (either on host or on guest) is not allowed to change the
   VF's MAC address "forever" (well, until you reload the PF driver,
   but that requires destroying and recreating every single VF, which
   isn't something you can require).

The solution is to keep the restoration of config at the same place,
but to set the *admin MAC* to the address you want the VF to have -
when the VF net driver is later initialized (as a part of re-binding
to the VF net driver) its MAC will be initialized to the current value
of the admin MAC.

In order to properly restore the original state of an SRIOV VF when
we're finished with it, we need to save the MAC address of the VF
itself (not just the admin MAC address for the VF that is stored in
the PF). But that can only be done when the VF is still bound to the
host's netdev driver, and we have always done the saving of device
config after the VF is already bound to vfio-pci. This patch prepares
us for adding a save of the VF's MAC by calling the function that
saves netconfig earlier in the device preparation, before we've
unbound it from the host netdev driver.

These two operations will need to be separated so that saving of the
original config is done before detaching the host net driver, and
setting the new config is done after attaching vfio-pci. This patch
splits the single function into two, but for now calls them together
(to make bisecting easier if there is a regression).

virHostdevNetConfigReplace() and virHostdevNetConfigRestore() are
modified to use the new virNetDev*NetConfig() functions.

Note that due to the VF's original MAC addresses being saved after it
has already been un-bound from the host net driver, the actual current
VF MAC address won't be saved (because it no longer exists) - only the
"admin MAC" will be saved. This reflects existing behavior that will
be fixed in an upcoming patch.

This patch modifies the macvtap passthrough setup to use
virNetDevSaveNetConfig()+virNetDevSetConfig() instead of
virNetDevReplaceNetConfig() or virNetDevReplaceMacAddress(), and the
teardown to use virNetDevReadNetConfig()+virNetDevSetConfig() instead
of virNetDevRestoreNetConfig() or virNetDevRestoreMacAddress().

Since the older functions only saved/restored the admin MAC and vlan
tag (which is incorrect) and the new functions save/restore the VF's
own MAC address and vlan tag (correct), this actually fixes a bug
(which was introduced by commit cb3fe38c, which was itself supposed
to be a fix for https://bugzilla.redhat.com/1113474 ).

The downside to this patch is that it causes an *apparent* regression
in that bug (because there will once again be an error reported if the
interface had previously been used for VFIO device assignment), but in
reality, the code hasn't been working for *any* case before this
current patch (at least not with any recent kernel). Anyway, that
"regression" will be fixed with an upcoming patch that fixes it the
*right* way.

These three functions are destined to replace
virNetDev(Replace|Restore)NetConfig() and
virNetDev(Replace|Restore)MacAddress(), which both do the save and set
together as a single step. We need to separate the save, read, and set
steps because there will be situations where we need to do something
else in between (in particular, we will need to rebind a VF's driver
after save but before set).

This patch creates the new functions, but doesn't call them - that
will come in a subsequent patch. Note that the new functions to
read/write the file that stores the original network config now uses
JSON rather than plaintext (it still recognizes the old format as well
though, so it won't get confused during an upgrade).

The hyperv panic notifier reports additional data in form of 5 registers
that are reported in the crash event from qemu. Log them into the VM log
file and report them as a warning so that admins can see the cause of
crash of their windows VMs.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1426176

For certain kinds of panic notifiers (notably hyper-v) qemu is able to
report some data regarding the crash passed from the guest.

Make the data accessible to the callback in qemu so that it can be
processed further.

Signed-off-by: NErik Skultety <eskultet@redhat.com>

Signed-off-by: NErik Skultety <eskultet@redhat.com>

For now, these only cover the unmanaged, i.e. user pre-created devices.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Format the mediated devices on the qemu command line as
-device vfio-pci,sysfsdev='/path/to/device/in/syfs'.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Since mdevs are just another type of VFIO devices, we should increase
the memory locking limit the same way we do for VFIO PCI devices.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

As goes for all the other hostdev device types, grant the qemu process
access to /dev/vfio/<mediated_device_iommu_group>.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Keep track of the assigned mediated devices the same way we do it for
the rest of hostdevs. Methods like 'Prepare', 'Update', and 'ReAttach'
are introduced by this patch.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

So far, the official support is for x86_64 arch guests so unless a
different device API than vfio-pci is available let's only turn on
support for PCI address assignment. Once a different device API is
introduced, we can enable another address type easily.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

This merely introduces virDomainHostdevMatchSubsysMediatedDev method that
is supposed to check whether device being cold-plugged does not already
exist in the domain configuration.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

This patch updates all of our security driver to start labeling the
VFIO IOMMU devices under /dev/vfio/ as well.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

A mediated device will be identified by a UUID (with 'model' now being
a mandatory <hostdev> attribute to represent the mediated device API) of
the user pre-created mediated device. We also need to make sure that if
user explicitly provides a guest address for a mdev device, the address
type will be matching the device API supported on that specific mediated
device and error out with an incorrect XML message.

The resulting device XML:
<devices>
  <hostdev mode='subsystem' type='mdev' model='vfio-pci'>
    <source>
      <address uuid='c2177883-f1bb-47f0-914d-32a22e3a8804'>
    </source>
  </hostdev>
</devices>
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Beside creation, disposal, getter, and setter methods the module exports
methods to work with lists of mediated devices.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Just to make the code a bit cleaner, move hostdev specific post parse
code to its own function just in case it grows in the future.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Just a tiny wrapper over the SCSI def clearing logic to drop some
if-else branches from a switch, mainly because extending the switch in
the future would render the current code with branching less readable.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Enforce virDomainHostdevSubsysType checking during compilation. Again,
one of a few spots in our code where we should enforce the typecast to
the enum type, thus not forgetting to update *all* switch occurrences
dealing with the give enum.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

We keep forgetting that older setups don't like 'index':

  CC     util/libvirt_util_la-virsysinfo.lo
cc1: warnings being treated as errors
util/virstoragefile.c: In function 'virStorageSourceFindByNodeName':
util/virstoragefile.c:3804: error: declaration of 'index' shadows a global declaration [-Wshadow]
/usr/include/string.h:489: error: shadowed declaration is here [-Wshadow]
Signed-off-by: NEric Blake <eblake@redhat.com>

Instead of generating all of the capabilities, let's test more of our
code by probing sysfs data.  This test needs quite some mocking for
now, but it paves the road for more future enhancements (hugepages
probing, for example).
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

All mocked functions are related to numactl/virNuma and rely only on
virsysfs, so the paths they touch can be nicely controlled.  And
because it is so nicely self-contained NUMA mock, it is named
numamock (instead of naming it after the test that will use it first).

We need top level API mock because some APIs might call libnuma
directly, e.g. virNumaIsAvailable(), virNumaGetMaxNode().
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

Bit more test data, this time with complete info copied, mainly with
cache information, so we can easily add tests for it.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

We'll stop generating the data on the fly, but rather test more of our
APIs.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

This way more drivers can utilize the functionality without copying
the code.  And we can therefore test it in one place for all of them.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

That file has only two exported files and each one of them has
different naming.  virNode is what all the other files use, so let's
use it.  It wasn't used before because the clash with public API
naming, so let's fix that by shortening the name (there is no other
private variant of it anyway).
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

There is no "node driver" as there was before, drivers have to do
their own ACL checking anyway, so they all specify their functions and
nodeinfo is basically just extending conf/capablities.  Hence moving
the code to src/conf/ is the right way to go.

Also that way we can de-duplicate some code that is in virsysfs and/or
virhostcpu that got duplicated during the virhostcpu.c split.  And
Some cleanup is done throughout the changes, like adding the vir*
prefix etc.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

There is no reason for it not to be in the utils, all global symbols
under that file already have prefix vir* and there is no reason for it
to be part of DRIVER_SOURCES because that is just a leftover from
older days (pre-driver modules era, I believe).
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

While on that, drop support for kernels from RHEL-5 era (missing
cpu/present file).  Also add some useful functions and export them.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>