Commit Graph

5795 Commits

Author SHA1 Message Date
Jiri Denemark
7c95619cb1 qemu: Introduce virQEMUCapsFormatCPUModels
This patch moves the CPU models formatting code from
virQEMUCapsFormatCache into a separate function.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-25 20:34:26 +01:00
Jiri Denemark
1bdcd7a4ee qemu: Introduce virQEMUCapsLoadCPUModels
This patch moves the CPU models parsing code from virQEMUCapsLoadCache
into a separate function.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-25 20:34:26 +01:00
Jiri Denemark
f9d57f2b57 qemu: Refresh caps in virQEMUCapsCacheLookupByArch
The function just returned cached capabilities without checking whether
they are still valid. We should check that and refresh the capabilities
to make sure we don't return stale data. In other words, we should do
what all other lookup functions do.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-25 20:34:26 +01:00
Jiri Denemark
72e5aa4e1e qemu: Refactor virQEMUCapsCacheLookup
The function is made a little bit more readable and the code which
refreshes cached capabilities if they are not valid any more was moved
into a separate function (virQEMUCapsCacheValidate) so that it can be
reused in other places.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-25 20:34:26 +01:00
Jiri Denemark
cd51b90fbf qemu: Don't return unusable virttype in domain capabilities
If a user asked for a KVM domain capabilities when KVM is not available,
we would happily return data we got when probing through TCG and
pretended they were relevant for KVM. Let's just report KVM is not
supported to avoid confusion.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-25 20:34:26 +01:00
Jiri Denemark
8f55eef246 qemu: Use saner defaults for domain capabilities
When domain capabilities were introduced we did not have enough data to
decide whether KVM works on the host or not and thus working legacy/VFIO
device assignment was used as a witness. Now that we know whether KVM
was enabled when probing QEMU capabilities (and thus we know it's
working), we can use this knowledge to provide better default value for
virttype.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-25 20:34:26 +01:00
Jiri Denemark
d87df9bd39 qemu: Discard caps cache when KVM availability changes
Since some may depend on the accelerator used when probing QEMU the
cache becomes invalid when KVM becomes available or if it is not
available anymore.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-25 20:34:26 +01:00
Jiri Denemark
25ba9c31f5 qemu: Enable KVM when probing capabilities
CPU related capabilities may differ depending on accelerator used when
probing. Let's use KVM if available when probing QEMU and fall back to
TCG. The created capabilities already contain all we need to distinguish
whether KVM or TCG was used:

    - KVM was used when probing capabilities:
        QEMU_CAPS_KVM is set
        QEMU_CAPS_ENABLE_KVM is not set

    - TCG was used and QEMU supports KVM, but it failed (e.g., missing
      kernel module or wrong /dev/kvm permissions)
        QEMU_CAPS_KVM is not set
        QEMU_CAPS_ENABLE_KVM is set

    - KVM was not used and QEMU does not support it
        QEMU_CAPS_KVM is not set
        QEMU_CAPS_ENABLE_KVM is not set

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-25 20:34:26 +01:00
Jiri Denemark
429a7b231c qemu: Probe KVM state earlier
Let's set QEMU_CAPS_KVM and QEMU_CAPS_ENABLE_KVM early so that the rest
of the probing code can use these capabilities to handle KVM/TCG replies
differently.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-25 20:34:26 +01:00
Jiri Denemark
e73447f693 qemu: Use -machine when probing capabilities via QMP
Using -machine instead of -M for QMP probing is safe because any QEMU
binary which is capable of QMP probing supports -machine.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-25 20:34:26 +01:00
Jiri Denemark
4c5d05ea8a qemu: Make QMP probing process reusable
The code that runs a new QEMU process to be used for probing
capabilities is separated into four reusable functions so that any code
that wants to probe a QEMU process may just follow a few simple steps:

    cmd = virQEMUCapsInitQMPCommandNew(...);
    virQEMUCapsInitQMPCommandRun(cmd);

    /* talk to the running QEMU process using its QMP monitor */

    if (reprobeIsRequired) {
        virQEMUCapsInitQMPCommandAbort(cmd, ...);
        virQEMUCapsInitQMPCommandRun(cmd);

        /* talk to the running QEMU process again */
    }

    virQEMUCapsInitQMPCommandFree(cmd);

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-25 20:34:26 +01:00
Michal Privoznik
c2a5a4e7ea virstring: Unify string list function names
We have couple of functions that operate over NULL terminated
lits of strings. However, our naming sucks:

virStringJoin
virStringFreeList
virStringFreeListCount
virStringArrayHasString
virStringGetFirstWithPrefix

We can do better:

virStringListJoin
virStringListFree
virStringListFreeCount
virStringListHasString
virStringListGetFirstWithPrefix

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2016-11-25 13:54:05 +01:00
Boris Fiuczynski
b178fa8ecb qemu: fix internal error: NUMA isn't available on this host
If libvirt is compiled without NUMACTL support starting libvirtd
reports a libvirt internal error "NUMA isn't available on this host"
without checking if NUMA support is compiled into the libvirt binaries.
This patch adds the missing NUMA support check to prevent the internal error.
It also includes a check if the cgroup controller cpuset is available before
using it.

The error was noticed when libvirtd was restarted with running domains and
on libvirtd start the qemuConnectCgroup gets called during qemuProcessReconnect.

Signed-off-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
2016-11-25 09:48:41 +01:00
Eric Farman
8c6d365373 qemu: Allow hotplug of vhost-scsi device
Adjust the device string that is built for vhost-scsi devices so that it
can be invoked from hotplug.

From the QEMU command line, the file descriptors are expect to be numeric only.
However, for hotplug, the file descriptors are expected to begin with at least
one alphabetic character else this error occurs:

  # virsh attach-device guest_0001 ~/vhost.xml
  error: Failed to attach device from /root/vhost.xml
  error: internal error: unable to execute QEMU command 'getfd':
  Parameter 'fdname' expects a name not starting with a digit

We also close the file descriptor in this case, so that shutting down the
guest cleans up the host cgroup entries and allows future guests to use
vhost-scsi devices.  (Otherwise the guest will silently end.)

Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
2016-11-24 12:16:23 -05:00
Eric Farman
9cc26dc622 qemu: Add vhost-scsi string for -device parameter
Open /dev/vhost-scsi, and record the resulting file descriptor, so that
the guest has access to the host device outside of the libvirt daemon.
Pass this information, along with data parsed from the XML file, to build
a device string for the qemu command line.  That device string will be
for either a vhost-scsi-ccw device in the case of an s390 machine, or
vhost-scsi-pci for any others.

Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
2016-11-24 12:16:19 -05:00
Eric Farman
fc0e627bac Introduce framework for a hostdev SCSI_host subsystem type
We already have a "scsi" hostdev subsys type, which refers to a single
LUN that is passed through to a guest.  But what of things where
multiple LUNs are passed through via a single SCSI HBA, such as with
the vhost-scsi target?  Create a new hostdev subsys type that will
carry this.

Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
2016-11-24 12:15:26 -05:00
Eric Farman
c271fc1f35 qemu: Introduce vhost-scsi capability
Do all the stuff for the vhost-scsi capability in QEMU,
so it's in place for our checks later.

Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
2016-11-24 12:15:26 -05:00
Marc Hartmayer
b270ef9981 qemu: Removed an outdated comment in qemuDomainSaveImageStartVM()
Removed the comment 'Set the migration source' as it isn't valid anymore
and 'start it up' isn't useful as qemuProcessStart() is already a
speaking name.

Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
2016-11-23 12:33:38 -05:00
Michal Privoznik
5d9c2c7081 qemu: Update cgroup on chardev hotplug
Just like in the previous commit, we are not updating CGroups on
chardev hot(un-)plug and thus leaving qemu unable to access any
non-default device users are trying to hotplug.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2016-11-23 16:38:02 +01:00
Michal Privoznik
085692c8bb qemu: Update cgroup on RNG hotplug
If users try to hotplug RNG device with a backend different to
/dev/random or /dev/urandom the whole operation fails as qemu is
unable to access the device. The problem is we don't update
device CGroups during the operation.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2016-11-23 16:37:57 +01:00
Nikolay Shirokovskiy
aaf2992d90 qemu: agent: fix unsafe agent access
qemuDomainObjExitAgent is unsafe.

First it accesses domain object without domain lock.
Second it uses outdated logic that goes back to commit 79533da1 of
year 2009 when code was quite different. (unref function
instead of unreferencing only unlocked and disposed object
in case of last reference and leaved unlocking to the caller otherwise).
Nowadays this logic may lead to disposing locked object
i guess.

Another problem is that the callers of qemuDomainObjEnterAgent
use domain object again (namely priv->agent) without domain lock.

This patch address these two problems.

qemuDomainGetAgent is dropped as unused.
2016-11-23 11:31:28 +03:00
Nikolay Shirokovskiy
3c1c56781d qemu: drop write-only agentStart 2016-11-23 11:31:14 +03:00
Nikolay Shirokovskiy
6ba861ae36 qemu: agent: cleanup agent error flag correctly
Sometimes after domain restart agent is unavailabe even
if it is up and running in guest. Diagnostic message is
"QEMU guest agent is not available due to an error"
that is 'priv->agentError' is set. Investiagion shows that
'priv->agent' is not NULL, so error flag is set probably
during domain shutdown process and not cleaned up eventually.

The patch is quite simple - just clean up error flag unconditionally
upon domain stop.

Other hunks address other cases when error flag is not cleaned up.

1. processSerialChangedEvent. We need to clean error flag
unconditionally here too. For example if upon first 'connected' event we
fail to connect and set error flag and then connect on second
'connected' event then error flag will remain set erroneously
and make agent unavailable.

2. qemuProcessHandleAgentEOF. If error flag is set and we get
EOF we need to change state (and diagnostic) from 'error' to
'not connected'.
2016-11-23 11:14:44 +03:00
Nikolay Shirokovskiy
f5109f20ff qemu: agent: remove redundant check 2016-11-23 11:14:28 +03:00
Nikolay Shirokovskiy
851ae08e3e qemu: agent: handle agent connection errors in one place
qemuConnectAgent return -1 or -2 in case of different errors.
A. -1 is a case of unsuccessuful connection to guest agent.
B. -2 is a case of destoyed domain during connection attempt.

All qemuConnectAgent callers handle the first error the same way
so let's move this logic into qemuConnectAgent itself. Patched
function returns 0 in case A and -1 in case B.
2016-11-23 11:14:11 +03:00
Marc Hartmayer
1c122e737e Refactoring: Use virHostdevIsSCSIDevice()
Use the util function virHostdevIsSCSIDevice() to simplify if
statements.

Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
2016-11-22 14:37:36 +01:00
Marc Hartmayer
505bc9b025 qemu: Fix improper union member access on hostdevs
Add missing checks if a hostdev is a subsystem/SCSI device before access
the union member 'subsys'/'scsi'.  Also fix indentation and simplify
qemuDomainObjCheckHostdevTaint().

Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
2016-11-22 14:37:36 +01:00
Sławek Kapłoński
6c98ac2c62 Forbid new-line char in name of new domain
New line character in name of domain is now forbidden because it
mess virsh output and can be confusing for users.
Validation of name is done in drivers, after parsing XML to avoid
problems with dissappeared domains which was already created with
new-line char in name.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2016-11-22 14:35:14 +01:00
Peter Krempa
b6afa9a8b5 qemu: monitor: Properly propagate the 'qemu_id' field through the matcher
Commit 3f71c79768 added 'qemu_id' field to track the id of the cpu
as reported by query-cpus. The patch did not include changes necessary
to propagate the id through the functions matching the data to the
libvirt cpu structures and thus all vcpus had id 0.
2016-11-22 10:44:17 +01:00
Peter Krempa
0df2524acb qemu: domain: Refresh vcpu halted state using qemuMonitorGetCpuHalted
Don't use qemuMonitorGetCPUInfo which does a lot of matching to get the
full picture which is not necessary and would be mostly discarded.

Refresh only the vcpu halted state using data from query-cpus.
2016-11-21 17:19:48 +01:00
Peter Krempa
5d885f4ff3 qemu: monitor: Extract halted state to a bitmap indexed by cpu id
We don't need to call qemuMonitorGetCPUInfo which is very inefficient to
get data required to update the vcpu 'halted' state.

Add a monitor helper that will retrieve the halted state and return it
in a bitmap so that it can be indexed easily.
2016-11-21 17:19:48 +01:00
Peter Krempa
3f71c79768 qemu: monitor: Extract qemu cpu id along with other data
Storing of the ID will allow simpler extraction of data present only in
query-cpus without the need to call qemuMonitorGetCPUInfo in statistics
paths.
2016-11-21 17:19:48 +01:00
Jiri Denemark
2e0d6cdec4 qemu_monitor_json: Don't check existence of "return" object
Whenever qemuMonitorJSONCheckError returns 0, the "return" object is
guaranteed to exist. Thus virJSONValueObjectGetObject will never fail to
get it. On the other hand, virJSONValueObjectGetArray may fail since the
"return" object may not be an array.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-21 16:14:52 +01:00
Peter Krempa
4fa7ba0b32 qemu: process: Set current vcpu count to maximum if it was not specified
Mimic qemu's behavior on the given command line.
2016-11-21 14:35:20 +01:00
Peter Krempa
d3734b7a1d qemu: parse: Assign maximum cpu count from topology if not provided
qemu uses this if 'maxcpus' is not present. Do the same in the parsing
code.
2016-11-21 14:35:20 +01:00
Peter Krempa
0d9a76de6d qemu: parse: Assign topology info earlier
Qemu can also use the topology to calculate the total vcpu count. To
allow parsing this move the assignment earlier.
2016-11-21 14:35:20 +01:00
Peter Krempa
d78a8c26c2 qemu: parse: Allow the 'cpus=' prefix for current cpu number
qemu allows following syntax:

  -smp [cpus=]n[,cores=cores][,threads=threads][,sockets=sockets][,maxcpus=maxcpus]

Allow the "cpus" prefix.
2016-11-21 14:35:20 +01:00
Peter Krempa
4d72d80665 qemu: parse: Validate that the VM has at least one cpu
Libvirt's code relies on this fact so don't allow parsing a command line
which would have none.

Libvirtd would crash in the post parse callback on such config.
2016-11-21 14:35:20 +01:00
Michal Privoznik
0c1bfd2c8d tests: Adapt to gluster_debug_level in qemu.conf
After a944bd92 we gained support for setting gluster debug level.
However, due to a space we haven't tested whether augeas file
actually works.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2016-11-21 10:50:48 +01:00
Jiri Denemark
d73422c186 cpu: Introduce virCPUConvertLegacy API
PPC driver needs to convert POWERx_v* legacy CPU model names into POWERx
to maintain backward compatibility with existing domains. This patch
adds a new step into the guest CPU configuration work flow which CPU
drivers can use to convert legacy CPU definitions.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-15 15:49:16 +01:00
Jiri Denemark
2a2ce08a6d cpu: Make models array in virCPUTranslate constant
The API doesn't change the array so let's make it constant.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-15 15:49:16 +01:00
Jiri Denemark
b7011dfe44 cpu: Rename cpuGetModels
The new name is virCPUGetModels.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-11-15 15:49:15 +01:00
Maxim Nestratov
007fb4388f qemu: fix libvirtd crash when querying halted cpus info
It was introduced by commit 7a51d9ebb, which started to use
monitor commands without job acquiring, which is unsafe and leads
to simultaneous access to vm->mon structure by different threads.

Crash backtrace is the following (shortened):

Program received signal SIGSEGV, Segmentation fault.
qemuMonitorSend (mon=mon@entry=0x7f4ef4000d20, msg=msg@entry=0x7f4f18e78640) at qemu/qemu_monitor.c:1011
1011        while (!mon->msg->finished) {

0  qemuMonitorSend () at qemu/qemu_monitor.c:1011
1  0x00007f691abdc720 in qemuMonitorJSONCommandWithFd () at qemu/qemu_monitor_json.c:298
2  0x00007f691abde64a in qemuMonitorJSONCommand at qemu/qemu_monitor_json.c:328
3  qemuMonitorJSONQueryCPUs at qemu/qemu_monitor_json.c:1408
4  0x00007f691abcaebd in qemuMonitorGetCPUInfo g@entry=false) at qemu/qemu_monitor.c:1931
5  0x00007f691ab96863 in qemuDomainRefreshVcpuHalted at qemu/qemu_domain.c:6309
6  0x00007f691ac0af99 in qemuDomainGetStatsVcpu at qemu/qemu_driver.c:18945
7  0x00007f691abef921 in qemuDomainGetStats  at qemu/qemu_driver.c:19469
8  qemuConnectGetAllDomainStats at qemu/qemu_driver.c:19559
9  0x00007f693382e806 in virConnectGetAllDomainStats at libvirt-domain.c:11546
10 0x00007f6934470c40 in remoteDispatchConnectGetAllDomainStats at remote.c:6267

(gdb) p mon->msg
$1 = (qemuMonitorMessagePtr) 0x0

This change fixes it by calling qemuDomainRefreshVcpuHalted only when job is acquired.

Signed-off-by: Maxim Nestratov <mnestratov@virtuozzo.com>
2016-11-15 17:39:24 +03:00
Laine Stump
70d15c9ac6 qemu: initially reserve one open pcie-root-port for hotplug
For machinetypes with a pci-root bus (all legacy PCI), libvirt will
make a "fake" reservation for one extra slot prior to assigning
addresses to unaddressed PCI endpoint devices in the domain. This will
trigger auto-adding of a pci-bridge for the final device to be
assigned an address *if that device would have otherwise instead been
the last device on the last available pci-bridge*; thus it assures
that there will always be at least one slot left open in the domain's
bus topology for expansion (which is important both for hotplug (since
a new pci-bridge can't be added while the guest is running) as well as
for offline additions to the config (since adding a new device might
otherwise in some cases require re-addressing existing devices, which
we want to avoid)).

It's important to note that for the above case (legacy PCI), we must
check for the special case of all slots on all buses being occupied
*prior to assigning any addresses*, and avoid attempting to reserve
the extra address in that case, because there is no free address in
the existing topology, so no place to auto-add a pci-bridge for
expansion (i.e. it would always fail anyway). Since that condition can
only be reached by manual intervention, this is acceptable.

For machinetypes with pcie-root (Q35, aarch64 virt), libvirt's
methodology for automatically expanding the bus topology is different
- pcie-root-ports are plugged into slots (soon to be functions) of
pcie-root as needed, and the new endpoint devices are assigned to the
single slot in each pcie-root-port. This is done so that the devices
are, by default, hotpluggable (the slots of pcie-root don't support
hotplug, but the single slot of the pcie-root-port does). Since
pcie-root-ports can only be plugged into pcie-root, and we don't
auto-assign endpoint devices to the pcie-root slots, this means
topology expansion doesn't compete with endpoint devices for slots, so
we don't need to worry about checking for all "useful" slots being
free *prior* to assigning addresses to new endpoint devices - as a
matter of fact, if we attempt to reserve the open slots before the
used slots, it can lead to errors.

Instead this patch just reserves one slot for a "future potential"
PCIe device after doing the assignment for actual devices, but only
if the only PCI controller defined prior to starting address
assignment was pcie-root, and only if we auto-added at least one PCI
controller during address assignment. This assures two things:

1) that reserving the open slots will only be done when the domain is
   initially defined, never at any time after, and

2) that if the user understands enough about PCI controllers that they
   are adding them manually, that we don't mess up their plan by
   adding extras - if they know enough to add one pcie-root-port, or
   to manually assign addresses such that no pcie-root-ports are
   needed, they know enough to add extra pcie-root-ports if they want
   them (this could be called the "libguestfs clause", since
   libguestfs needs to be able to create domains with as few
   devices/controllers as possible).

This is set to reserve a single free port for now, but could be
increased in the future if public sentiment goes in that direction
(it's easy to increase later, but essentially impossible to decrease)
2016-11-14 14:23:48 -05:00
Laine Stump
8d873a5a47 qemu: try to put ich9 sound device at 00:1B.0
Real Q35 hardware has an ICH9 chip that includes several integrated
devices at particular addresses (see the file docs/q35-chipset.cfg in
the qemu source). libvirt already attempts to put the first two sets
of ich9 USB2 controllers it finds at 00:1D.* and 00:1A.* to match the
real hardware. This patch does the same for the ich9 "HD audio"
device.

The main inspiration for this patch is that currently the *only*
device in a reasonable "workstation" type virtual machine config that
requires a legacy PCI slot is the audio device, Without this patch,
the standard Q35 machine created by virt-manager will have a
dmi-to-pci-bridge and a pci-bridge just for the sound device; with the
patch (and if you change the sound device model from the default
"ich6" to "ich9"), the machine definition constructed by virt-manager
has absolutely no legacy PCI controllers - any legacy PCI devices
(e.g. video and sound) are on pcie-root as integrated devices.
2016-11-14 14:23:01 -05:00
Laine Stump
d8bd837669 qemu: add a USB3 controller to Q35 domains by default
Previously we added a set of EHCI+UHCI controllers to Q35 machines to
mimic real hardware as closely as possible, but recent discussions
have pointed out that the nec-usb-xhci (USB3) controller is much more
virtualization-friendly (uses less CPU), so this patch switches the
default for Q35 machinetypes to add an XHCI instead (if it's
supported, which it of course *will* be).

Since none of the existing test cases left out USB controllers in the
input XML, a new Q35 test case was added which has *no* devices, so
ends up with only the defaults always put in by qemu, plus those added
by libvirt.
2016-11-14 14:22:23 -05:00
Laine Stump
807232203a qemu: don't force-add a dmi-to-pci-bridge just on principle
Now the a dmi-to-pci-bridge is automatically added just as it's needed
(when a pci-bridge is being added), we no longer have any need to
force-add one to every single Q35 domain.
2016-11-14 14:21:43 -05:00
Laine Stump
0702f48ef4 qemu: auto-add pcie-root-port/dmi-to-pci-bridge controllers as needed
Previously libvirt would only add pci-bridge devices automatically
when an address was requested for a device that required a legacy PCI
slot and none was available. This patch expands that support to
dmi-to-pci-bridge (which is needed in order to add a pci-bridge on a
machine with a pcie-root), and pcie-root-port (which is needed to add
a hotpluggable PCIe device). It does *not* automatically add
pcie-switch-upstream-ports or pcie-switch-downstream-ports (and
currently there are no plans for that).

Given the existing code to auto-add pci-bridge devices, automatically
adding pcie-root-ports is fairly straightforward. The
dmi-to-pci-bridge support is a bit tricky though, for a few reasons:

1) Although the only reason to add a dmi-to-pci-bridge is so that
   there is a reasonable place to plug in a pci-bridge controller,
   most of the time it's not the presence of a pci-bridge *in the
   config* that triggers the requirement to add a dmi-to-pci-bridge.
   Rather, it is the presence of a legacy-PCI device in the config,
   which triggers auto-add of a pci-bridge, which triggers auto-add of
   a dmi-to-pci-bridge (this is handled in
   virDomainPCIAddressSetGrow() - if there's a request to add a
   pci-bridge we'll check if there is a suitable bus to plug it into;
   if not, we first add a dmi-to-pci-bridge).

2) Once there is already a single dmi-to-pci-bridge on the system,
   there won't be a need for any more, even if it's full, as long as
   there is a pci-bridge with an open slot - you can also plug
   pci-bridges into existing pci-bridges. So we have to make sure we
   don't add a dmi-to-pci-bridge unless there aren't any
   dmi-to-pci-bridges *or* any pci-bridges.

3) Although it is strongly discouraged, it is legal for a pci-bridge
   to be directly plugged into pcie-root, and we don't want to
   auto-add a dmi-to-pci-bridge if there is already a pci-bridge
   that's been forced directly into pcie-root.

Although libvirt will now automatically create a dmi-to-pci-bridge
when it's needed, the code still remains for now that forces a
dmi-to-pci-bridge on all domains with pcie-root (in
qemuDomainDefAddDefaultDevices()). That will be removed in a future
patch.

For now, the pcie-root-ports are added one to a slot, which is a bit
wasteful and means it will fail after 31 total PCIe devices (30 if
there are also some PCI devices), but helps keep the changeset down
for this patch. A future patch will have 8 pcie-root-ports sharing the
functions on a single slot.
2016-11-14 14:19:36 -05:00
Laine Stump
b2c887844f qemu: only force an available legacy-PCI slot on domains with pci-root
Andrea had the right idea when he disabled the "reserve an extra
unused slot" bit for aarch64/virt. For *any* PCI Express-based
machine, it is pointless since 1) an extra legacy-PCI slot can't be
used for hotplug, since hotplug into legacy PCI slots doesn't work on
PCI Express machinetypes, and 2) even for "coldplug" expansion,
everybody will want to expand using Express controllers, not legacy
PCI.

This patch eliminates the extra slot reserve unless the system has a
pci-root (i.e. legacy PCI)
2016-11-14 14:18:49 -05:00
Laine Stump
5266426b21 qemu: assign nec-xhci (USB3) controller to a PCIe address when appropriate
The nec-usb-xhci device (which is a USB3 controller) has always
presented itself as a PCI device when plugged into a legacy PCI slot,
and a PCIe device when plugged into a PCIe slot, but libvirt has
always auto-assigned it to a legacy PCI slot.

This patch changes that behavior to auto-assign to a PCIe slot on
systems that have pcie-root (e.g. Q35 and aarch64/virt).

Since we don't yet auto-create pcie-*-port controllers on demand, this
means a config with an nec-xhci USB controller that has no PCI address
assigned will also need to have an otherwise-unused pcie-*-port
controller specified:

   <controller type='pci' model='pcie-root-port'/>
   <controller type='usb' model='nec-xhci'/>

(this assumes there is an otherwise-unused slot on pcie-root to accept
the pcie-root-port)
2016-11-14 14:18:06 -05:00