Commit Graph

9563 Commits

Author SHA1 Message Date
Ján Tomko
bd622e2a21 qemu: do not revert to NULL bandwidth
Otherwise an attempt to set an invalid value:
  virsh domiftune rhel8.2 vnet0 --outbound 4294968
on an interface with no bandwidth set crashes.

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Fixes: f02e21cb33
https://bugzilla.redhat.com/show_bug.cgi?id=1800505
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
2020-02-10 16:41:51 +01:00
Daniel P. Berrangé
2621d48f00 gnulib: delete all gnulib integration
This deletes all trace of gnulib from libvirt. We still
have the keycodemapdb submodule to deal with. The simple
solution taken was to update it when running autogen.sh.

Previously gnulib could auto-trigger refresh when running
'make' too. We could figure out a solution for this, but
with the pending meson rewrite it isn't worth worrying
about, given how infrequently keycodemapdb changes.

Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2020-02-07 15:03:54 +00:00
zhenwei pi
26badd13e8 qemu: support Panic Crashloaded event handling
Pvpanic device supports bit 1 as crashloaded event, it means that
guest actually panicked and run kexec to handle error by guest side.

Handle crashloaded as a lifecyle event in libvirt.

Test case:
Guest side:
before testing, we need make sure kdump is enabled,
1, build new pvpanic driver (with commit from upstream
   e0b9a42735f2672ca2764cfbea6e55a81098d5ba
   191941692a3d1b6a9614502b279be062926b70f5)
2, insmod new kmod
3, enable crash_kexec_post_notifiers,
  # echo 1 > /sys/module/kernel/parameters/crash_kexec_post_notifiers
4, trigger kernel panic
  # echo 1 > /proc/sys/kernel/sysrq
  # echo c > /proc/sysrq-trigger

Host side:
1, build new qemu with pvpanic patches (with commit from upstream
   600d7b47e8f5085919fd1d1157f25950ea8dbc11
   7dc58deea79a343ac3adc5cadb97215086054c86)
2, build libvirt with this patch
3, handle lifecycle event and trigger guest side panic
  # virsh event stretch --event lifecycle
  event 'lifecycle' for domain stretch: Crashed Crashloaded
  events received: 1

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
2020-02-07 14:05:25 +00:00
Jiri Denemark
c6ff3d1535 qemu_capabilities: Disable CPU models on old s390 machine types
Starting a KVM domain on s390 with old machine type (such as
s390-ccw-virtio-2.5) and without any guest CPU model configured fails
with

    CPU models are not available: KVM doesn't support CPU models

QEMU error. This is cause by libvirt using host-model CPU as the default
CPU based on QEMU reporting "host" CPU model as being the default one
(see commit v5.9.0-402-g24d8202294: qemu: Use host-model CPU on s390 by
default). However, even though both QEMU and KVM support CPU models on
s390 and QEMU can give us the host-model CPU, we can't use it with old
machine types which only support -cpu host.

https://bugzilla.redhat.com/show_bug.cgi?id=1795651

Reported-by: Christian Ehrhardt <paelzer@gmail.com>
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-07 09:19:02 +01:00
Jiri Denemark
80791859ac qemu: Pass machine type to virQEMUCapsIsCPUModeSupported
The usability of a specific CPU mode may depend on machine type, let's
prepare for this by passing it to virQEMUCapsIsCPUModeSupported.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-07 09:19:02 +01:00
Stefan Berger
12fcdede80 qemu: Extend QEMU with tpm-spapr support
Extend QEMU with tpm-spapr support. Assign a device address to the
vTPM device model.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>
2020-02-05 19:57:10 +01:00
Stefan Berger
20d9340268 qemu: Extend QEMU capabilities with 'tpm-spapr'
Extend the QEMU capabilties with tpm-spapr support.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>
2020-02-05 19:57:10 +01:00
Stefan Berger
914cb83218 conf: Add support for tpm-spapr to domain XML
This patch adds support for the tpm-spapr device model for ppc64. The XML for
this type of TPM looks as follows:

 <tpm model='tpm-spapr'>
   <backend type='emulator'/>
 </tpm>

Extend the documentation.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>
2020-02-05 19:57:10 +01:00
Stefan Berger
21b6f41d95 conf: Introduce VIR_DOMAIN_TPM_MODEL_DEFAULT as default model
Introduce VIR_DOMAIN_TPM_MODEL_DEFAULT as a default model which we use
in case the user does not provide a model in the device XML. It has
the TIS's previous value of '0'. In the post parsing function
we change this default value to 'TIS' to have the same model as before.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>
2020-02-05 19:57:10 +01:00
Daniel P. Berrangé
03c532cf97 src: assume sys/sysmacros.h always exists on Linux
All our supported Linux distros now have this header.
It has never existed on FreeBSD / macOS / Mingw.

Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2020-02-04 14:00:45 +00:00
Daniel P. Berrangé
cc46e137eb src: convert code to use virPipe APIs
This addreses portability to Windows and standardizes
error reporting. This fixes a number of places which
failed to set O_CLOEXEC or failed to report errors.

Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2020-02-04 14:00:44 +00:00
Daniel P. Berrangé
bfeb56b3ad src: remove sys/wait.h from many files
Most code now uses the virProcess / virCommand APIs, so
the need for sys/wait.h is quite limited. Removing this
include removes the dependency on GNULIB providing a
dummy sys/wait.h for Windows.

Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2020-02-04 14:00:44 +00:00
Peter Krempa
54030892f5 qemuDomainBlockPivot: Copy bitmaps backing checkpoints for virDomainBlockCopy
Use qemuBlockBitmapsHandleBlockcopy to calculate bitmaps to copy over
for a block-copy job.

We copy them when pivoting to the new image as at that point we are
certain that we don't dirty any bitmap unnecessarily.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-04 13:45:34 +01:00
Peter Krempa
26f07f6870 qemu: block: Introduce function to calculate bitmap handling for block-copy
Add a function calculating which bitmaps to copy to the mirror during
a block-copy operation.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-04 13:45:33 +01:00
Peter Krempa
41c7e5c2a6 qemu: block: Add validator for bitmap chains accross backing chains
Add a validator which checks that a bitmap spanning multiple backing
chain members doesn't look broken. The current rules are that no
intermediate birmaps are missing (unfortunately it's hard to know
whether the topmost or bottommost bitmap is missing) and none of the
components is inconsistent.

We can obviously improve it over time.

The validator is also tested against the existing bitmap data we have
for the backup merging test as well as some of the existing broken
bitmap synthetic test cases.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-04 13:45:33 +01:00
Peter Krempa
ccd4228aff qemu: blockjob: Store 'flags' for all the block job types
The flags may control important aspects of the block job which may
influence also the termination of the job. Store the 'flags' for all
the block job types.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-04 13:45:33 +01:00
Peter Krempa
9ba804a1d1 qemu: blockjob: Store 'jobflags' with block job data
Add a variable which will store the contents of the 'flags' variable as
passed in by the individual block jobs. Since the flags may influence
behaviour of the jobs it's important to preserve them to the
finalization steps.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-04 13:45:33 +01:00
Peter Krempa
d69470a18a virJSONValueNewArray: Use g_new0 to allocate and remove NULL checks from callers
Use the glib allocation function that never returns NULL and remove the
now dead-code checks from all callers.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-04 13:45:33 +01:00
Peter Krempa
5ddfac1169 qemu: block: Extract calls of qemuBlockGetNamedNodeData into a helper function
Create a wrapper for qemuBlockGetNamedNodeData named
qemuBlockGetNamedNodeData. The purpose of the wrapper is to integrate
the monitor handling functionality and in the future possible
qemuCaps-based flags.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-04 13:45:32 +01:00
Peter Krempa
8e94e29010 qemu: checkpoint: Track and relabel images for bitmap merging
Allow qemu access to modify backing files in case when we want to delete
a checkpoint.

This patch adds tracking of which images need to be relabelled when
calculating the transaction, the code to relabel them and rollback.

To verify that stuff works we also output the list of images to relabel
into the test case output files in qemublocktest.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-04 13:45:32 +01:00
Peter Krempa
30bc426071 qemu: checkpoint: Introduce support for deleting checkpoints accross snapshots
Allow deleting of checkpoints when snapshots were created along. The
code tracks and modifies the checkpoint list so that backups can still
be taken with such a backing chain. This unfortunately requires to
rename few bitmaps (by copying and deleting them) in some cases.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-04 13:45:32 +01:00
Ján Tomko
2df925459c qemu: tpm: remove unused labels
Remove all the labels that are now redundant.

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2020-02-03 19:44:39 +01:00
Ján Tomko
9226a627eb qemu: tpm: use g_autoptr where applicable
This requires stealing one cmd pointer before returning it.

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2020-02-03 19:44:39 +01:00
Ján Tomko
3f897afda6 qemu: tpm: use g_autofree
Mark eligible declarations as g_autofree and remove
the corresponding VIR_FREE calls.

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2020-02-03 19:44:39 +01:00
Ján Tomko
9994bee5f2 qemu: tpm: remove unused pidfile variable
qemuExtTPMSetupCgroup declares pidfile but never uses it.

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2020-02-03 19:44:39 +01:00
Ján Tomko
0a125c7144 virBufferTrim: do not accept len
Always trim the full specified suffix.

All of the callers outside of tests were passing either
strlen or the actual length of the string.

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2020-02-03 19:44:38 +01:00
Michal Privoznik
a37a8c569d Drop virAtomic module
Now, that every use of virAtomic was replaced with its g_atomic
equivalent, let's remove the module.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-02 16:36:58 +01:00
Michal Privoznik
7390ff3caa src: Drop virAtomicIntDecAndTest() with g_atomic_int_dec_and_test()
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-02 16:36:56 +01:00
Michal Privoznik
574678a27f src: Replace virAtomicIntInc() with g_atomic_int_add()
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-02-02 16:36:54 +01:00
Ján Tomko
62d75cdcc6 qemu: drop unused variable
The g_auto conversion made clang realize the variable is unused:
../../src/qemu/qemu_domain.c:10349:36: error: unused variable
    'cfg' [-Werror,-Wunused-variable]
    g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Fixes: 20fa2bc6e5
2020-01-31 17:02:26 +01:00
Ján Tomko
e8d5eb0cde qemu: Fix domain ID allocation
The rewrite to use GLib's atomic ops functions changed the behavior
of virAtomicIntInc - before it returned the pre-increment value.

Most of the callers using its value were adjusted, but the one
in qemuDriverAllocateID was not. If libvirtd would reconnect to
a running domain during startup, the next started domain would get
the same ID:

$ virsh list
 Id   Name       State
--------------------------
 1    f28live    running
 1    f28live1   running

Use the g_atomic_add function directly (as recommended in viratomic.h)
and add 1 to the result.

This also restores the usual numbering from 1 instead of 0.

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Fixes: 7b9645a7d1
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2020-01-31 16:11:50 +01:00
Daniel Henrique Barboza
4427903722 qemu_domain_address.c: turn qemuDomainFillDeviceIsolationGroup to void
Starting on commit 1f43393283, qemuDomainFillDeviceIsolationGroup()
returns 0 in all circunstances. Let's turn it to 'void' make it
clearer that the function will not fail. This also spares a
check for < 0 return in qemu_hotplug.c. The
qemuDomainFillDeviceIsolationGroupIter() callback now returns
0 at all times - which is already happening anyway.

Refer to 1f43393283 commit message for more details on why
the function was changed to never return an error.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 15:25:33 +01:00
Daniel Henrique Barboza
02ad5d2359 qemu_domain.c: turn qemuDomainChrDefDropDefaultPath to void
qemuDomainChrDefDropDefaultPath() returns an int, but it's
always returning 0. Callers are checking for result < 0 to
run their cleanup code needlessly.

Turn the function to 'void' and adjust the callers.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 15:25:33 +01:00
Daniel Henrique Barboza
db780004a9 qemu_domain.c: removing unneeded cleanup labels
Previous patches deprecated some 'cleanup' labels. Let's remove
them.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 15:25:33 +01:00
Daniel Henrique Barboza
20fa2bc6e5 qemu_domain.c: use g_autoptr when possible
Avoid some of the virObjectUnref() calls by using g_autoptr.
Aside from the 'cleanup' label in qemuDomainSetFakeReboot(),
all other now deprecated cleanup labels will be removed in
the next patch.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 15:25:33 +01:00
Daniel Henrique Barboza
ae9f630e50 qemu_domain.c: use g_autofree when possible
Use g_autofree to remove VIR_FREE() calls used for cleanups.
Labels that became deprecated will be removed in a later
patch.

In qemuDomainSetupDisk(), the 'dst' variable is not used at
all and could be removed.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 15:25:33 +01:00
Daniel Henrique Barboza
749ec34a56 qemu_domain.c: remove redundant virObjectUnref()
The 'caps' variable in qemuDomainObjPrivateXMLParseAutomaticPlacement()
is set to auto clean via g_autoptr(), but a 'virObjectUnref(caps)' is
being executed in the 'cleanup' label.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 15:25:33 +01:00
Peter Krempa
b9e87908db qemuMigrationCookieAddNBD: Fix filling of 'capacity' when blockdev is used
With -blockdev we must look up via the nodename rather than the 'drive'
alias which is not present any more.

This fixes the pre-creation of storage volumes on migration with
non-shared storage.

https://bugzilla.redhat.com/show_bug.cgi?id=1793263

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 14:28:29 +01:00
Peter Krempa
d409411213 qemuMigrationCookieAddNBD: Remove 'ret' variable and 'cleanup' label
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 14:28:29 +01:00
Peter Krempa
45eefb2c78 qemuMigrationCookieAddNBD: Use virHashNew and automatic freeing of virHashTablePtr
Swithc to the helper which doesn't require checking of the return value.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 14:28:29 +01:00
Peter Krempa
464345e153 qemuMigrationCookieAddNBD: Move monitor call out of the loop
The data is gathered only once so we can move the whole block which
fetches the data out of the loop and get rid of the logic which
prevents multiple calls.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 14:28:29 +01:00
Peter Krempa
8efeeb59a6 qemuMigrationCookieAddNBD: Use glib memory allocators
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 14:28:29 +01:00
Peter Krempa
3093822d1d qemuMigrationCookieNBD: Extract embedded struct
Extract the struct so that it's type has a name.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 14:28:28 +01:00
Peter Krempa
bdff9d4513 qemuMigrationCookieAddNBD: Exit early if there are no disks
Refactor the logic to skip the body of the function if there's nothing
to do.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 14:28:28 +01:00
Peter Krempa
6eab924daa Remove checking of return value of virHashNew
There are two calls to virHashNew which check the return value. It's not
necessary any more as virHashNew always returns a valid pointer.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2020-01-31 14:28:28 +01:00
Ján Tomko
49882b3337 Add a space before ending a comment
Also add a space after the start in some of the cases.

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2020-01-30 12:32:03 +01:00
Laine Stump
8a226ddb36 qemu: add wait-unplug to qemu migration status enum
Aside from itinerant error (actually warning) messages due to an
unrecognized response from qemu, this isn't even necessary - the
migration proceeds successfully to completion anyway.

(I'm not sure where to see this status reported in the API though - do
we need to add an extra state, or recognition of a new event somewhere?)

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2020-01-29 15:33:29 -05:00
Laine Stump
2758f680b7 qemu: allow migration with assigned PCI hostdev if <teaming> is set
Normally a PCI hostdev can't be migrated, so
qemuMigrationSrcIsAllowedHostdev() won't permit it. In the case of a a
hostdev network interface that has <teaming type='transient'/> set,
QEMU will automatically unplug the device prior to migration, and
re-plug a corresponding device on the destination. This patch modifies
qemuMigrationSrcIsAllowedHostdev() to allow domains with those devices
to be migrated.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2020-01-29 15:33:29 -05:00
Laine Stump
eb9f6cc4b3 qemu: support interface <teaming> functionality
The QEMU driver uses the <teaming type='persistent|transient'
persistent='blah'/> element to setup a "failover" pair of devices -
the persistent device must be a virtio emulated NIC, with the only
extra configuration being the addition of ",failover=on" to the device
commandline, and the transient device must be a hostdev NIC
(<interface type='hostdev'> or <interface type='network'> with a
network that is a pool of SRIOV VFs) where the extra configuration is
the addition of ",failover_pair_id=$aliasOfVirtio" to the device
commandline. These new options are supported in QEMU 4.2.0 and later.

Extra qemu-specific validation is added to ensure that the device
type/model is appropriate and that the qemu binary supports these
commandline options.

The result of this will be:

1) The virtio device presented to the guest will have an extra bit set
in its PCI capabilities indicating that it can be used as a failover
backup device. The virtio guest driver will need to be equipped to do
something with this information - this is included in the Linux
virtio-net driver in kernel 4.18 and above (and also backported to
some older distro kernels). Unfortunately there is no way for libvirt
to learn whether or not the guest driver supports failover - if it
doesn't then the extra PCI capability will be ignored and the guest OS
will just see two independent devices. (NB: the current virtio guest
driver also requires that the MAC addresses of the two NICs match in
order to pair them into a bond).

2) When a migration is requested, QEMu will automatically unplug the
transient/hostdev NIC from the guest on the source host before
starting migration, and automatically re-plug a similar device after
restarting the guest CPUs on the destination host. While the transient
NIC is unplugged, all network traffic will go through the
persistent/virtio device, but when the hostdev NIC is plugged in, it
will get all the traffic. This means that in normal circumstances the
guest gets the performance advantage of vfio-assigned "real hardware"
networking, but it can still be migrated with the only downside being
a performance penalty (due to using an emulated NIC) during the
migration.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2020-01-29 15:33:29 -05:00
Laine Stump
cad65f222f qemu: add capabilities flag for failover feature
Presence of the virtio-net-pci option called "failover" indicates
support in a qemu binary of a simplistic bonding of a virtio-net
device with another PCI device. This feature allows migration of
guests that have a network device assigned to a guest with VFIO, by
creating a network bond device in the guest consisting of the
VFIO-assigned device and a virtio-net-pci device, then temporarily
(and automatically) unplugging the VFIO net device prior to migration
(and hotplugging an equivalent device on the migration
destination). (The feature is called "failover" because the bond
device uses the vfio-pci netdev for normal guest networking, but
"fails over" to the virtio-net-pci netdev once the vfio-pci device is
unplugged for migration.)

Full functioning of the feature also requires support in the
virtio-net driver in the guest OS (since that is where the bond device
resides), but if the "failover" commandline option is present for the
virtio-net-pci device in qemu, at least the qemu part of the feature
is available, and libvirt can add the proper options to both the
virtio-net-pci and vfio-pci device commandlines to indicate qemu
should attempt doing the failover during migration.

This patch just adds the qemu capabilities flag "virtio-net.failover".

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2020-01-29 15:33:29 -05:00