Commit Graph
100 Commits
Author SHA1 Message Date
Laine Stump b89c4991da network: add an nftables backend for network driver's firewall construction
Support using nftables to setup the firewall for each virtual network,
rather than iptables. The initial implementation of the nftables
backend creates (almost) exactly the same ruleset as the iptables
backend, determined by running the following commands on a host that
has an active virtual network:

  iptables-save >iptables.txt
  iptables-restore-translate -f iptables.txt

(and the similar ip6tables-save/ip6tables-restore-translate for an
IPv6 network). Correctness of the new backend was checked by comparing
the output of:

  nft list ruleset

when the backend is set to iptables and when it is set to nftables.

This page was used as a guide:

  https://wiki.nftables.org/wiki-nftables/index.php/Moving_from_iptables_to_nftables

The only differences between the rules created by the nftables backed
vs. the iptables backend (aside from a few inconsequential changes in
display order of some chains/options) are:

1) When we add nftables rules, rather than adding them in the
system-created "filter" and "nat" tables, we add them in a private
table (ie only we should be using it) created by us called "libvirt"
(the system-created "filter" and "nat" tables can't be used because
adding any rules to those tables directly with nft will cause failure
of any legacy application attempting to use iptables when it tries to
list the iptables rules (e.g. "iptables -S").

(NB: in nftables only a single table is required for both nat and
filter rules - the chains for each are differentiated by specifying
different "hook" locations for the toplevel chain of each)

2) Since the rules that were added to allow tftp/dns/dhcp traffic from
the guests to the host are unnecessary in the context of nftables,
those rules aren't added.

(Longer explanation: In the case of iptables, all rules were in a
single table, and it was always assumed that there would be some
"catch-all" REJECT rule added by "someone else" in the case that a
packet didn't match any specific rules, so libvirt added these
specific rules to ensure that, no matter what other rules were added
by any other subsystem, the guests would still have functional
tftp/dns/dhcp. For nftables though, the rules added by each subsystem
are in a separate table, and in order for traffic to be accepted, it
must be accepted by *all* tables, so just adding the specific rules to
libvirt's table doesn't help anything (as the default for the libvirt
table is ACCEPT anyway) and it just isn't practical/possible for
libvirt to find *all* other tables and add rules in all of them to
make sure the traffic is accepted. libvirt does this for firewalld (it
creates a "libvirt" zone that allows tftp/dns/dhcp, and adds all
virtual network bridges to that zone), however, so in that case no
extra work is required of the sysadmin.)

3) nftables doesn't support the "checksum mangle" rule (or any
equivalent functionality) that we have historically added to our
iptables rules, so the nftables rules we add have nothing related to
checksum mangling.

(NB: The result of (3) is that if you a) have a very old guest (RHEL5
era or earlier) and b) that guest is using a virtio-net network
device, and c) the virtio-net device is using vhost packet processing
(the default) then DHCP on the guest will fail. You can work around
this by adding <driver name='qemu'/> to the <interface> XML for the
guest).

There are certainly much better nftables rulesets that could be used
instead of those implemented here, and everything is in place to make
future changes to the rules that are used simple and free of surprises
(e.g. the rules that are added have coresponding "removal" commands
added to the network status so that we will always remove exactly the
rules that were previously added rather than trying to remove the
rules that "the current build of libvirt would have added" (which will
be incorrect the first time we run a libvirt with a newly modified
ruleset). For this initial implementation though, I wanted the
nftables rules to be as identical to the iptables rules as possible,
just to make it easier to verify that everything is working.

The backend can be manually chosen using the firewall_backend setting
in /etc/libvirt/network.conf. libvirtd/virtnetworkd will read this
setting when it starts; if there is no explicit setting, it will check
for availability of FIREWALL_BACKEND_DEFAULT_1 and then
FIREWALL_BACKEND_DEFAULT_2 (which are set at build time in
meson_options.txt or by adding -Dfirewall_backend_default_n=blah to
the meson commandline), and use the first backend that is available
(ie, that has the necessary programs installed). The standard
meson_options.txt is set to check for nftables first, and then
iptables.

Although it should be very safe to change the default backend from
iptables to nftables, that change is left for a later patch, to show
how the change in default can be undone if someone really needs to do
that.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Tested-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:20:07 -04:00
Laine Stump 865eea30f4 meson: stop looking for iptables/ip6tables/ebtables at build time
This was the only reason we required the iptables and ebtables
packages at build time, and many other external commands already have
their binaries found at runtime by looking through $PATH (virCommand
automatically does this), so we may as well do it for these commands
as well.

Since we no longer need iptables or iptables at build time, we can
also drop the BuildRequires for them from the rpm specfile.

Inspired-by: 6aa2fa38b0
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:20:07 -04:00
Laine Stump 110383fa30 network: save network status when firewall rules are reloaded
In the case that a new version of libvirt is started that uses
different rules to build the network firewall, we need to re-save the
status so that when the network is destroyed (or the *next* time
libvirt is restarted and wants to remove/re-add the firewall), it will
have the proper information to perform the firewall removal.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:20:07 -04:00
Laine Stump 97061d576b network: use previously saved list of firewall removal commands
When destroying a network, the network driver has always assumed that
it knew what firewall rules had been added as the network was
started. This was usually correct - I only recall one time in the past
that the firewall rules added by libvirt were changed. But if the
exact rules used for a network *were* ever changed from one
build/version of libvirt to another, then we would end up attempting
to remove rules that hadn't been added, and could possibly *not*
remove rules that had been added.

The solution to this to not make such brash assumptions about the
past, but instead to save (in the network status object at network
start time) a list of all the rules needed to remove the rules that
were added for the network, and then use that saved list during
network destroy to remove exactly what was previous added.

Beyond making net-destroy more precise, there are other benefits:

1) We can change the details of the rules we add for networks from one
build/release of libvirt to another and painlessly upgrade.

2) The user can switch from one firewall backend to another by simply
changing the setting in network.conf and restarting
libvirtd/virtnetworkd.

In both cases, the restarted libvirtd/virtnetworkd will remove all the
rules that had been previously added (based on the network status),
and then add new rules (saving the new removal commands back into the
network status)

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:20:07 -04:00
Laine Stump 0fa79844a1 conf: add a virFirewall object to virNetworkObj
This virFirewall object will store the list of actions required to
remove the firewall that was added for the currently active instance
of the network, so it has been named "fwRemoval" (and when parsed into
XML, the <firewall> element will have the name "fwRemoval").

There are no uses of the fwRemoval object in the virNetworkObj yet,
but everything is in place to add it to the XML when formatted, parse
it from the XML when reading network status, and free the virFirewall
object when the virNetworkObj is freed.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:20:07 -04:00
Laine Stump df9a505961 util: new functions virFirewallParseXML() and virFirewallFormat()
These functions convert a virFirewall object to/from XML so that it
can be serialized to disk (in a virNetworkObj's status file) and
restored later (e.g. after libvirtd/virtnetworkd is restarted).

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:58 -04:00
Laine Stump b77b2fc314 util: new function virFirewallNewFromRollback()
virFirewallNewFromRollback() creates a new virFirewall object that
contains a copy of the "rollback" commands from an existing
virFirewall object, but in reverse order. The intent is that this
virFirewall be saved and used later to remove the firewall rules that
were added for a network.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:48 -04:00
Laine Stump d24b7501dc util: add name attribute to virFirewall
This will be used to label (via "name='blah'") a firewall when it is
formatted to XML and written to the network status.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:36 -04:00
Laine Stump e1b6b0646f network: turn on auto-rollback for the rules added for virtual networks
So far this will only affect what happens if there is some failure
while applying the firewall rules; the rollback rules aren't yet
persistent beyond that time. More work is needed to remember the
rollback rules while the network is active, and use those rules to
remove the firewall for the network when it is destroyed.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:36 -04:00
Laine Stump e23907635c util: implement rollback rule autocreation for iptables commands
If the VIR_FIREWALL_TRANSACTION_AUTO_ROLLBACK flag is set, each time
an iptables command is executed that is adding a rule or chain, a
corresponding command that will *delete* the same rule/chain is
constructed and added to the list of rollback commands. If we later
want to undo the entire firewall, we can just run those commands.

This isn't yet used anywhere, since
VIR_FIREWALL_TRANSACTION_AUTO_ROLLBACK isn't being set.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:36 -04:00
Laine Stump f94c82b0a6 util: new functions to support adding individual firewall rollback commands
In the past virFirewall required all rollback commands for a group
(those commands necessary to "undo" any rules that had been added in
that group in case of a later failure) to be manually added by
switching into the virFirewall object into "rollback mode" and then
re-calling the inverse of the exact virFirewallAddCmd*() APIs that had
been called to add the original rules (ie. for each
"iptables --insert" command, for rollback we would need to add a
command with all arguments identical except that "--insert" would be
replaced by "--delete").

Because nftables can't search for rules to remove by comparing all the
arguments (it instead expects *only* a handle that is provided via
stdout when the rule was originally added), we won't be able to follow
the iptables method and manually construct the command to undo any
given nft command by just duplicating all the args of the command
(except the action). Instead we will need to be able to automatically
create a rollback command at the time the rule-adding command is
executed (e.g. an "nft delete rule" command that would include the
rule handle returned in stdout by an "nft add rule" command).

In order to make this happen, we need to be able to 1) learn whether
the user of the virFirewall API desires this behavior (handled by a new
transaction flag called VIR_FIREWALL_TRANSACTION_AUTO_ROLLBACK that
can be retrieved with the new virFirewallTransactionGetFlags() API),
and 2) add a new command to the current group's rollback command list (with
the new virFirewallAddRollbackCmd()).

We will actually use this capability in an upcoming patch.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:36 -04:00
Laine Stump c737f225a9 network: framework to call backend-specific function to init private filter chains
Modify networkSetupPrivateChains() in the network driver to accept a
firewallBackend argument so it will know which backend to call. (right
now it always calls the iptables version of the lower level function,
but in the future it could instead call the nftables version based on
configuration).

But networkSetupPrivateChains() was being called with virOnce(), and
virOnce() doesn't support calling functions that require an argument
(it's based on pthread_once(), which accepts no arguments, so it's not
something we can easily fix in our implementation of virOnce()). To
solve this dilemma, this patch eliminates use of virOnce() by adding a
static lock, and putting all of networkSetupPrivateChains() (including
the setting of "chainInitDone") inside a lock guard - now the places
that used to call it via virOnce() can safely call it directly
instead (adding in the necessary argument to specify backend).

(If it turns out to be significant, we could optimize this by checking
for chainInitDone outside the lock guard, returning immediately if
it's already set, and then moving the setting of chainInitDone up to
the top of the guarded section.)

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:36 -04:00
Laine Stump 64b966558c network: support setting firewallBackend from network.conf
It still can have only one useful value ("iptables"), but once a 2nd
value is supported, it will be selectable by setting
"firewall_backend=nftables" in /etc/libvirt/network.conf.

If firewall_backend isn't set in network.conf, then libvirt will check
to see if FIREWALL_BACKEND_DEFAULT_1 is available and, if so, set
that. (Since FIREWALL_BACKEND_DEFAULT_1 is currently "iptables", this
means checking to see it the iptables binary is present on the
system).  If the default backend isn't available, that is considered a
fatal error (since no networks can be started anyway), so an error is
logged and startup of the network driver fails.

NB: network.conf is itself created from network.conf.in at build time,
and the advertised default setting of firewall_backend (in a commented
out line) is set from the meson_options.txt setting
"firewall_backend_default_1". This way the conf file will have correct
information no matter what ordering is chosen for default backend at
build time (as more backends are added, settings will be added for
"firewall_backend_default_n", and those will be settable in
meson_options.txt and on the meson commandline to change the ordering
of the auto-detection when no backend is set in network.conf).

virNetworkLoadDriverConfig() may look more complicated than necessary,
but as additional backends are added, it will be easier to add checks
for those backends (and to re-order the checks based on builders'
preferences).

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:18 -04:00
Laine Stump 45c4527f36 network: add (empty) network.conf file to distribution files
This file is generated from network.conf.in because it will soon have
an item that must be modified according to meson buildtime config.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:18 -04:00
Laine Stump 9293644d8a util/network: new virFirewallBackend enum
(This paragraph is for historical reference only, described only to
avoid confusion of past use of the name with its new use) In a past
life, virFirewallBackend had been a private static in virfirewall.c
that was set at daemon init time, and used to globally (i.e. for all
drivers in the daemon) determine whether to directly execute iptables
commands, or to run them indirectly via the firewalld passthrough
API. This was removed in commit d566cc55, since we decided that using
the firewalld passthrough API is never appropriate.

Now the same enum, virFirewallBackend, is being reintroduced, with a
different meaning and usage pattern. It will be used to pick between
using nftables commands or iptables commands (in either case directly
handled by libvirt, *not* via firewalld). Additionally, rather than
being a static known only within virfirewall.c and applying to all
firewall commands for all drivers, each virFirewall object will have
its own backend setting, which will be set during virFirewallNew() by
the driver who wants to add a firewall rule.

This will allow the nwfilter and network drivers to each have their
own backend setting, even when they coexist in a single unified
daemon. At least as important as that, it will also allow an instance
of the network driver to remove iptables rules that had been added by
a previous instance, and then add nftables rules for the new instance
(in the case that an admin, or possibly an update, switches the driver
backend from iptables to nftable)

Initially, the enum will only have one usable value -
VIR_FIREWALL_BACKEND_IPTABLES, and that will be hardcoded into all
calls to virFirewallNew(). The other enum value (along with a method
of setting it for each driver) will be added later, when it can be
used (when the nftables backend is in the code).

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:18 -04:00
Laine Stump 5543179cea util: determine ignoreErrors value when creating virFirewallCmd, not when applying
We know at the time a virFirewallCmd is created (with
virFirewallAddCmd*()) whether or not we will later want to ignore
errors encountered when attempting to apply that command - if
ignoreErrors is set in the AddCmd or if the group has already had
VIR_FIREWALL_TRANSACTION_IGNORE_ERRORS set, then we ignore the errors.

Rather than setting the fwCmd->ignoreErrors only according to the arg
sent to virFirewallAddCmdFull(), and then later (at ApplyCmd-time)
combining that with the group transactionFlags setting (and passing it
all the way down the call chain), just combine the two flags right
away and store this final value in fwCmd->ignoreErrors when the
virFirewallCmd is created (thus avoiding the need to look at anything
other than fwCmd->ignoreErrors at the time the command is applied). Once
that is done, we can simply grab ignoreErrors from the object down in
virFirewallApply() rather than cluttering up the argument list on the
entire call chain.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:18 -04:00
Laine Stump 4ee30ecd57 util: add -w/--concurrent when applying a FirewallCmd rather than when building it
We will already need a separate function for virFirewallApplyCmd for
iptables vs. nftables, but the only reason for needing a separate
function for virFirewallAddCmd* is that iptables/ebtables need to have
an extra arg added for locking (to prevent multiple iptables commands
from running at the same time). We can just as well add in the
-w/--concurrent during virFirewallApplyCmd, so move the arg-add to
ApplyCmd to keep AddCmd simple.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:18 -04:00
Laine Stump ad96ee74ce util: check for 0 args when applying iptables rule
In normal practice a virFirewallCmd should never have 0 args by the
time it gets to the Apply stage, but at some time while debugging one
of the other patches in this series, exactly that happened (due to a
bug that was since squashed), and having a check for it helped
debugging, so let's permanently check for it.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:18 -04:00
Laine Stump 67362e6328 util: rename virNetFilterAction to iptablesAction, and add VIR_ENUM_DECL/IMPL
I had originally named these as VIR_NETFILTER_* because I assumed the
same enum would eventually be used by our nftables backend as well as
iptables. But it turns out that in most cases it's not possible to
delete an nftables rule, so we just never used the enum anyway, so
this patch is renaming the values to IPTABLES_ACTION_*, and taking
advantage of the newly defined (via VIR_ENUM_DECL/IMPL)
iptablesActionTypeToString() to replace all the ternary operators used
to translate the enum into a string for the iptables commandline with
iptablesActionTypeToString().

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:18 -04:00
Laine Stump 0817344ba7 util: change name of virFirewallRule to virFirewallCmd
These objects aren't rules, they are commands that are executed that
may create a firewall rule, delete a firewall rule, or simply list the
existing firewall rules. It's confusing for the objects to be called
"Rule" (especially in the case of the function
virFirewallRemoveRule(), which doesn't remove a rule from the
firewall, it takes one of the objects out of the list of commands to
execute! In order to remove a rule from the host's firewall, you have
to Add a "rule" (now "cmd" aka command) to the list that will, when
applied/run, remove a rule from the host firewall.)

Changing the name to virFirewallCmd makes it all much less confusing.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:18 -04:00
Laine Stump 5ac0dc4cef util: #define the names used for private packet filter chains
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:18 -04:00
Laine Stump b4913820ec network: make all iptables functions used only in network_iptables.c static
Now that the toplevel iptables functions have been moved out of the
linux bridge driver into network_iptables.c, all of the utility
functions are used only within that same file, so simplify it.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:18 -04:00
Laine Stump 01fd85fed9 network: move all functions manipulating iptables rules into network_iptables.c
Although initially we will add exactly the same rules for the nftables
backend, the two may (hopefully) soon diverge as we take advantage of
nftables features that weren't available in iptables. When we do that,
there will need to be a different version of these functions (currently in
bridge_driver_linux.c) for each backend:

  networkAddFirewallRules()
  networkRemoveFirewallRules()
  networkSetupPrivateChains()

Although it will mean duplicating some amount of code (with just the
function names changed) for the nftables backend, this patch moves all
of the rule-related code in the above three functions into iptables*()
functions in network_iptables.c, and changes the functions in
bridge_driver_linux.c to call the iptables*() functions. When we make
a different backend, it will only need to make equivalents of those 3
functions publicly available to the upper layer.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:18 -04:00
Laine Stump e1f6d2c205 util/network: move viriptables.[ch] from util to network directory
These functions are only ever used by the network driver, and are so
specific to the network driver's usage of iptables that they likely
won't ever be used elsewhere. The files are renamed to
network_iptables.[ch] to be more in line with driver-specific file
naming conventions.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2024-05-22 23:19:18 -04:00
Laine Stump 41fe852487 Set stubDriverName from hostdev driver model attribute during pci device setup
commit v9.10.0-129-g8b93d78c83 (first appearing in libvirt-10.0.0) was
supposed to allow forcing a PCI hostdev to be bound to a particular
driver by adding <driver model='blah'/> to the XML for the
device. Unfortunately, a single line was missed during the final
changes to the patch prior to pushing, and the result was that the
driver model could be set to *anything* and it would be accepted but
just ignored.

This patch adds the missing line, which will set the stubDriverName
field of the virPCIDevice object from the hostdev object as the
virPCIDevice is being created. This ends up being used by
virPCIDeviceBindToStub() as the driver that it binds the device to.

Fixes: 8b93d78c83
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2024-02-20 11:19:44 -05:00
Laine Stump 493b49d67f news: document auto-selection of VFIO variant drivers
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2024-01-15 09:32:22 +01:00
Laine Stump 82e2fac297 qemu: automatically bind to a vfio variant driver, if available
Rather than always binding to the vfio-pci driver, use the new
function virPCIDeviceFindBestVFIOVariant() to see if the running
kernel has a VFIO variant driver available that is a better match for
the device, and if one is found, use that instead.

virPCIDeviceFindBestVFIOVariant() function reads the modalias file for
the given device from sysfs, then looks through
/lib/modules/${kernel_release}/modules.alias for the vfio_pci alias
that matches with the least number of wildcard ('*') fields.

The appropriate "VFIO variant" driver for a device will be the PCI
driver implemented by the discovered module - these drivers are
compatible with (and provide the entire API of) the standard vfio-pci
driver, but have additional device-specific APIs that can be useful
for, e.g., saving/restoring state for migration.

If a specific driver is named (using <driver model='blah'/> in the
device XML), that will still be used rather than searching
modules.alias; this makes it possible to force binding of vfio-pci if
there is an issue with the auto-selected variant driver.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-01-08 01:00:11 -05:00
Laine Stump 8b93d78c83 conf: support manually specifying VFIO variant driver in <hostdev> XML
This patch makes it possible to manually specify which VFIO variant
driver to use for PCI hostdev device assignment, so that, e.g. you
could force use of a VFIO "variant" driver, with e.g.

  <driver model='mlx5_vfio_pci'/>

or alternately to force use of the generic vfio-pci driver with

  <driver model='vfio-pci'/>

when libvirt would have normally (after applying a subsequent patch)
found a "better match" for a device in the active kernel's
modules.alias file. (The main potential use of this manual override
would probably be to work around a bug in a new VFIO variant driver by
temporarily not using that driver).

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-01-08 01:00:08 -05:00
Laine Stump 956e1ca6aa tests: remove explicit <driver name='vfio'/> from hostdev test cases
The long-deprecated use of <driver name='vfio|xen|kvm'/> in domain xml
for <hostdev> devices was only ever necessary during the period when
libvirt (and the Linux kernel) supported both VFIO and "legacy KVM"
styles of hostdev device assignment for QEMU. This became pointless
many years ago when legacy KVM device assignment was removed from the
kernel, and support for that style of device assignment was completely
disabled in the libvirt source in 2019 (commit
v5.6.0-316-g2e7225ea8c).

Nevertheless, there were instances of <driver name='vfio'/> in the
unit test data that were then (unnecessarily) propagated to several
more tests over the years. This patch cleans out those unnecessary
explicit settings of driver name='vfio' in all QEMU unit test data,
proving that the attribute is no longer (externally) needed. (A later
patch which adds a 2nd attribute to the <driver> element will include
a test case that explicitly exercises the driver name attribute).

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-01-07 23:59:00 -05:00
Laine Stump 9363c1cb69 xen: explicitly set hostdev driver.name at runtime, not in postparse
Xen only supports a single type of PCI hostdev assignment, so it is
superfluous to have <driver name='xen'/> peppered throughout the
config. It *is* necessary to have the driver type explicitly set in
the hostdev object before calling into the hypervisor-agnostic "hostdev
manager" though (otherwise the hostdev manager doesn't know whether it
should do Xen-specific setup, or VFIO-specific setup).

Historically, the Xen driver has checked for "default" driver name
(i.e. not set in the XML), and set it to "xen', during the XML
postparse, thus guaranteeing that it will be set by the time the
object is sent to the hostdev manager at runtime, but also setting it
so early that a simple round-trip of parse-format results in the XML
always containing an explicit <driver name='xen'/>, even if that
wasn't specified in the original XML.

The QEMU driver *doesn't* set driver.name during postparse though;
instead, it waits until domain startup time (or device attach time for
hotplug), and sets the driver.name then. The result is that a
parse-format round trip of the XML in the QEMU driver *doesn't* add in
the <driver name='vfio'/>.

This patch modifies the Xen driver to behave similarly to the QEMU
driver - the PostParse just checks for a driver.name that isn't
supported by the Xen driver, and any explicit setting to "xen" is
deferred until domain runtime rather than during the postparse, thus
Xen domain XML also doesn't get extraneous <driver name='xen'/>.

This delayed setting of driver.name of course results in slightly
different xml2xml parse-format results, so the unit test data is
modified accordingly.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-01-07 23:59:00 -05:00
Laine Stump b9a1e7c436 conf: replace virHostdevIsVFIODevice with virHostdevIsPCIDevice
virHostdevIsVFIODevice() and virDomainDefHasVFIOHostdev() are only ever
called from the QEMU driver, and in the case of the QEMU driver, any
PCI hostdev by definition uses VFIO, so really all these callers only
need to know if the device is a PCI hostdev.

(It turned out that the less specific virHostdevIsPCIDevice() already
existed in hypervisor/virhostdev.c, so I had to remove one of them;
since conf is a lower level directory than hypervisor, and the
function is called from conf, keeping the copy in hypervisor would
have required moving its caller (virDomainDefHasPCIHostdev()) into
hypervisor as well, so I just removed the copy in hypervisor.)

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-01-07 23:58:44 -05:00
Laine Stump bb1acb9ca2 conf: use new common parser/formatter for hostdev driver in network XML
Now if a new attribute is added to <driver>, we only need to update
the formatting/parsing in one place.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-01-07 23:57:09 -05:00
Laine Stump 195522ae87 conf: split out hostdev <driver> parse/format to their own functions
This is done so that we can re-use the same parser/formatter for
<network> and <networkport>

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-01-07 23:57:09 -05:00
Laine Stump 8bc3f01080 conf: use virDeviceHostdevPCIDriverInfo in network and networkport objects
The next step in consolidating parsing/formatting of the <driver>
element of these objects using a common struct and common code. This
eliminates the virNetworkForwardDriverNameType enum which is nearly
identical to virDeviceHostdevPCIDriverName (the only non-identical bit
was just because they'd gotten out of sync over time) and replaces its
uses with a virDeviceHostdevPCIDriverInfo (which is a struct that
contains a virDeviceHostdevPCIDriverName).

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-01-07 23:57:09 -05:00
Laine Stump e04ca000bd conf: put hostdev PCI backend into a struct
The new struct is virDeviceHostdevPCIDriverInfo, and the "backend"
enum in the hostdevDef will be replaced with a
virDeviceHostdevPCIDriverInfo named "driver'. Since the enum value in
this new struct is called "name", it means that all references to
"backend" will become "driver.name".

This will allow easily adding other items for new attributes in the
<driver> element / C struct, which will be useful once we are using
this new struct in multiple places.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-01-07 23:57:09 -05:00
Laine Stump e7d31d8b00 conf: normalize hostdev <driver> parsing to simplify adding new attr
The hostdev version of the <driver> subelement appears in four places:

 * The domain XML in the <hostdev> and <interface type='hostdev'>
   elements (that's 2)

 * The network XML inside <forward> when the network is a pool of
   SRIOV VFs

 * the <networkport> XML, which is used to communicate between the
   hypervisor driver and network driver.

In order to make the pending addition of a new attribute to <driver>
in all these cases simpler, this patch refactors the parsing of
<driver> in all four places to use virXMLProp*() and
virXMLFormatElement().

Making all of the different instances of the separate parse/format for
<driver> look nearly identical will make it easier to see that the
upcoming patch that converges all four to use a common
parser/formatter is a functional NOP.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-01-07 23:57:09 -05:00
Laine Stump a435e7e6c8 conf: move/rename hostdev PCI driver type enum to device_conf.h
Currently this enum is defined in domain_conf.h and named
virDomainHostdevSubsysPCIDriverType. I want to use it in parts of the
network and networkport config, so am moving its definition to
device_conf.h which is / can be included by all interested parties,
and renaming it to match the name of the corresponding XML attribute
("driver name"). The name change (which includes enum values) does cause a
lot of churn, but it's all mechanical.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-01-07 23:57:09 -05:00
Laine Stump deefaf8f1c schema: consolidate RNG for all hostdev <driver> elements
The exact same element can appear in <hostdev> and <interface
type='hostdev'>, and nearly identical in <network> and <networkport>
(these latter two don't include "xen" as a possible driver, but that's
coincidental - there's no reason Xen couldn't also use the VF pools in
virtual networks, it just doesn't).

This patch modifies all 4 to use the same <ref name="hostdevDriver"/>
so that it is simpler to add something new.

A side effect of this patch is that the grammar for the <interface>
element in domain XML has been tightened up a bit - previously it was
accepted by the schema (but nonsensical) to have virtio and network
interface options specified; as a part of making the two different
<driver> choices each a complete element (rather than each being a
collection of attributes and subelements) these extra
attributes/subelements that were irrelevant to the hostdev-type
<driver> were made to be valid only for an emulated interface's
<driver>.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-01-07 23:57:09 -05:00
Laine Stump 568efef729 util: properly deal with VFIO module name vs. driver name
Historically libvirt hasn't differentiated between the name of a
loadable kernel module, and the name of the device driver that module
implements, but these two names can be (and usually are) at least
subtly different.

For example, the loadable module called "vfio_pci" implements a PCI
driver called "vfio-pci". We have always used the name "vfio-pci" both
to load the module (with modprobe) and to check (in
/sys/bus/pci/drivers) if the driver is available. (This has happened
to work because modprobe "normalizes" all the names it is given by
replacing "-" with "_", so "vfio-pci" works for both loading the
module and checking for the driver.)

When we recently gained the ability to manually specify the driver for
"virsh nodedev-detach", the fragility of this system became apparent -
if a user gave the "driver name" as "vfio_pci", then we would modprobe
the module correctly, but then erroneously believe it hadn't been
loaded because /sys/bus/pci/drivers/vfio_pci didn't exist. For manual
specification of the driver name, we could deal with this by telling
the user "always use the correct name for the driver, don't assume
that it has the same name as the module", but it would still end up
confusing people, especially since some drivers do use underscore in
their name (e.g. the mlx5_vfio_pci driver/module).

This will only get worse when an upcoming patch starts automatically
determining the driver to use for VFIO-assigned devices - it will look
in the kernel's modules.alias file to find "best" VFIO variant
*module* for a device, and 3 out of 4 current examples of
vfio-pci/variant drivers have a mismatch between module name and
driver name, so the current code would end up properly loading the
module, but then erroneously think that the driver wasn't available.

This patch makes the code more forgiving by

1) checking for both $drivername and underscore($drivername) in
   /sys/bus/pci/drivers

2) when we determine a module needs to be loaded, look at the link in
   /sys/module/$modulename/driver/pci:$drivername to determine the
   name of the driver we need to bind to the device(rather than just
   assuming the driver has the same name as the module

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-01-07 23:57:08 -05:00
Laine Stump 9953ab321e rpcgen: use proper operators when comparing types
flake8 (run on all python scripts as a part of the syntax checks)
version 6.1.0 (on macOS 14) issued many complaints like this on the
new rpcgen python scripts:

[...]libvirt/scripts/rpcgen/rpcgen/lexer.py:57:17: E721 do not compare types, for exact checks use `is` / `is not`, for instance checks use `isinstance()`

This patch changes all [type] == [type] to use "is" instead of "==",
and similarly to use "is not" instead of "!=".

(flake8 5.03, e.g. on Fedora 38, is just fine with using "==" and "!=",
but python on both likes "is" and "is not")

Fixes: commit v9.9.0-24-g8ec79e5e14
Fixes: commit v9.9.0-22-gca3f025011
Fixes: commit v9.9.0-21-g031efb691f
Fixes: commit v9.9.0-20-g8c8b97685b

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2023-11-06 12:24:30 -05:00
Laine Stump 9231566146 build: suppress "ignoring duplicate libraries" warning on macOS
Xcode 15, which provides the compiler toolchain for building libvirt
on macOS has switched to a new linker that warns about duplicated
"-lblah" options on the ld commandline. In practice this is impossible
to prevent in a large project, and also harmless.

Fortunately the new ld command also has an option,
-no_warn_duplicate_libraries, that supresses this harmless/pointless
warning, meson has a simple way to check if that option is supported,
and libvirt's meson.build files already have examples of adding an
option to the ld commandline if it's available.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2023-11-03 15:56:37 -04:00
Laine Stump 3d9019e64f tests: ignore $__CF_USER_TEXT_ENCODING in env during commandtest
This environment variable is supposedly set according to the contents
of ~/.CFUserTextEncoding, and certainly on MacOS 14 (Sonoma) it is set
in the environment of child processes created by execve() (used by
virCommand()), causing commandtest to fail. (However, the value that is
shown in $__CF_USER_TEXT_ENCODING during the test 1) is not in the
environment of the shell the test is run from, and 2) doesn't match
the contents of ~/.CFUserTextEncoding.)

It is true, though, that filtering out this environment setting from
the test results permits commandtest to pass on macOS 14 (Sonoma).

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2023-11-03 13:31:26 -04:00
Laine Stump 1622012cc4 specfile: use correct option for nbdkit in mingw build
commit v9.8.0-40-g7cbd8c4230 changed the name of the option that
enables/disables nbdkit support in the build from "libnbd" to
"nbdkit", but one use of "libnbd=disabled" was missed in
libvirt.specfile.in - the meson commandline for mingw.

This patch changes that line to "-Dnbdkit=disabled", thus unbreaking
the rpm build.

Resolves: https://gitlab.com/libvirt/libvirt/-/issues/550
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2023-10-23 07:52:12 -04:00
Laine Stump b3715f6e0e NEWS: document support for VFIO variant drivers
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-08-25 15:24:58 -04:00
Laine Stump bbfcf18f50 docs: update description of virsh nodedev-detach --driver option
--driver can now be used to specify a specific driver to bind to the
device being detached from the host driver (e.g. vfio-pci-igbvf), not
just the *type* of driver (e.g. "vfio" or "xen", which are unnecessary
anyway, since they are implicit in which hypervisor driver is in use)

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-08-25 15:24:58 -04:00
Laine Stump 10e8a518a0 qemu: turn two multiline log messages into single line
Normally I wouldn't bother with a change like this, but I was touching
the function anyway, and wanted to leave it looking nice and tidy.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-08-24 23:36:18 -04:00
Laine Stump 24beaffec3 node_device: support binding other drivers with virNodeDeviceDetachFlags()
In the past, the only allowable values for the "driver" field of
virNodeDeviceDetachFlags() were "kvm" or "vfio" for the QEMU driver,
and "xen" for the libxl driver. Then "kvm" was deprecated and removed,
so the driver name became essentially irrelevant (because it is always
called via a particular hypervisor driver, and so the "xen" or "vfio"
can be (and almost always is) implied.

With the advent of VFIO variant drivers, the ability to explicitly
specify a driver name once again becomes useful - it can be used to
name the exact VFIO driver that we want bound to the device in place
of vfio-pci, so this patch allows those other names to be passed down
the call chain, where the code in virpci.c can make use of them.

The names "vfio", "kvm", and "xen" retain their special meaning, though:

  1) because there may be some application or configuration that still
     calls virNodeDeviceDetachFlags() with driverName="vfio", this
     single value is substituted with the synonym of NULL, which means
     "bind the default driver for this device and hypervisor". This
     will currently result in the vfio-pci driver being bound to the
     device.

  2) in the case of the libxl driver, "xen" means to use the standard
     driver used in the case of Xen ("pciback").

  3) "kvm" as a driver name always results in an error, as legacy KVM
     device assignment was removed from the kernel around 10 years ago.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-08-24 23:36:18 -04:00
Laine Stump 928296b044 util: honor stubDriverName when probing/binding stub driver for a device
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-08-24 23:36:18 -04:00
Laine Stump 2d9c9445b9 util: probe stub driver from within function that binds to stub driver
virPCIProbeStubDriver() and virPCIDeviceBindToStub() both have
very similar code that locally sets a driver name (based on
stubDriverType). These two functions are each also called in just one
place (virPCIDeviceDetach()), with just a small bit of validation code
in between.

To eliminate the "duplicated" code (which is going to be expanded
slightly in upcoming patches to support manually or automatically
picking a VFIO variant driver), this patch modifies
virPCIProbeStubDriver() to take the driver name as an argument
(rather than the virPCIDevice object), and calls it from within
virPCIDeviceBindToStub() (rather than from that function's caller),
using the driverName it has just figured out with the
now-not-duplicated code.

(NB: Since it could be used to probe *any* driver module, the name is
changed to virPCIProbeDriver()).

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-08-24 23:36:18 -04:00
Laine Stump 6ce071f609 util: permit existing binding to VFIO variant driver
Before a PCI device can be assigned to a guest with VFIO, that device
must be bound to the vfio-pci driver rather than to the device's
normal host driver. The vfio-pci driver provides APIs that permit QEMU
to perform all the necessary operations to make the device accessible
to the guest.

In the past vfio-pci was the only driver that supplied these APIs, but
there are now vendor/device-specific "VFIO variant" drivers that
provide the basic vfio-pci driver functionality/API while adding
support for device-specific operations (for example these
device-specific drivers may support live migration of certain
devices).  All that is needed to make this functionality available is
to bind the vendor-specific "VFIO variant" driver to the device
(rather than the generic vfio-pci driver, which will continue to work,
just without the extra functionality).

But until now libvirt has required that all PCI devices being assigned
to a guest with VFIO specifically have the "vfio-pci" driver bound to
the device. So even if the user manually binds a shiny new
vendor-specific VFIO variant driver to the device (and puts
"managed='no'" in the config to prevent libvirt from changing the
binding), libvirt will just fail during startup of the guest (or
during hotplug) because the driver bound to the device isn't exactly
"vfio-pci".

Beginning with kernel 6.1, it's possible to determine from the sysfs
directory for a device whether the currently-bound driver is the
vfio-pci driver or a VFIO variant - the device directory will have a
subdirectory called "vfio-dev". We can use that to appropriately widen
the list of drivers that libvirt will allow for VFIO device
assignment.

This patch doesn't remove the explicit check for the exact "vfio-pci"
driver (since that would cause systems with pre-6.1 kernels to behave
incorrectly), but adds an additional check for the vfio-dev directory,
so that any VFIO variant driver is acceptable for libvirt to continue
setting up for VFIO device assignment.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-08-24 23:36:18 -04:00
Laine Stump 222b66974e util: rename virPCIDeviceGetDriverPathAndName
Instead, call it virPCIDeviceGetCurrentDriverPathAndName() to avoid
confusion with the device name that is stored in the virPCIDevice
object - that one is not necessarily the name of the current driver
for the device, but could instead be the driver that we want to be
bound to the device in the future.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-08-24 23:36:18 -04:00
Laine Stump 1bb9617971 util: add stub driver name to virPCIDevice object
There can be many different drivers that are of the type "VFIO", so
add the driver name to the object and allow getting/setting it.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-08-24 23:36:18 -04:00
Laine Stump cd2843f546 util: use "stubDriverType" instead of just "stubDriver"
In the past we just kept track of the type of the "stub driver" (the
driver that is bound to a device in order to assign it to a
guest). The next commit will add a stubDriverName to go along with
type, so lets use stubDriverType for the existing enum to make it
easier to keep track of whether we're talking about the name or the
type.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-08-24 23:36:18 -04:00
Laine Stump a8262cb331 qemu: don't add --mac-addr option to passt commandline
When I implemented passt support in libvirt, I saw the --mac-addr
option on the passt commandline, immediately assumed that this was
used for setting the guest interface's mac address somewhere within
passt, and read no further. As a result, "--mac-addr" is always added
to the passt commandline, specifying the setting from <mac
addr='blah'/> in the guest's interface config.

But as pointed out in this bugzilla comment:

https://bugzilla.redhat.com/2184967#c8

That is *not at all* what passt's --mac-addr option does. Instead, it
is used to force the *remote* mac address for incoming traffic to a
specific value. So setting --mac-addr results in all traffic on the
interface having the same (the guest's) mac address for both source
and destination in all traffic. Surprisingly, this still works, so
nobody noticed it during testing.

The proper thing is to not specify any mac address to passt - the
remote MAC addresses can and should remain untouched, and the local
MAC address will end up being known to passt just by the guest sending
out packets with that MAC address.

Reported-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
2023-08-02 19:33:02 -04:00
Laine Stump 8419dd3b69 qemu: set SELinux label of passt process to its own binary's label
set useBinarySpecificLabel = true when calling qemuSecurityCommandRun
for the passt process, so that the new process context will include
the binary-specific label that should be used for passt (passt_t)
rather than svirt_t (as would happen if useBinarySpecificLabel was
false). (The MCS part of the label, which is common to all child
processes related to a particular qemu domain instance, is also set).

Resolves: https://bugzilla.redhat.com/2172267
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-03-10 14:09:36 -05:00
Laine Stump 75056f61f1 security: make it possible to set SELinux label of child process from its binary
Normally when a child process is started by libvirt, the SELinux label
of that process is set to virtd_t (plus an MCS range). In at least one
case (passt) we need for the SELinux label of a child process label to
match the label that the binary would have transitioned to
automatically if it had been run standalone (in the case of passt,
that label is passt_t).

This patch modifies virSecuritySELinuxSetChildProcessLabel() (and all
the functions above it in the call chain) so that the toplevel
function can set a new argument "useBinarySpecificLabel" to true. If
it is true, then virSecuritySELinuxSetChildProcessLabel() will call
the new function virSecuritySELinuxContextSetFromFile(), which uses
the selinux library function security_compute_create() to determine
what would be the label of the new process if it had been run
standalone (rather than being run by libvirt) - the MCS range from the
normally-used label is added to this newly derived label, and that is
what is used for the new process rather than whatever is in the
domain's security label (which will usually be virtd_t).

In order to easily verify that nothing was broken by these changes to
the call chain, all callers currently set useBinarySpecificPath =
false, so all behavior should be completely unchanged. (The next
patch will set it to true only for the case of running passt.)

https://bugzilla.redhat.com/2172267
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-03-10 14:09:29 -05:00
Laine Stump 60afe39576 security: make args to virSecuritySELinuxContextAddRange() const
Neither of these are modified anywhere in the function, and the
function will soon be called with an arg that actually is a const.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-03-10 14:09:23 -05:00
Laine Stump a53c1d6f84 util: add an API to retrieve the resolved path to a virCommand's binary
The binary to be exec'ed by virExec() is stored in
virCommand::args[0], and is resolved to a full absolute path (stored
in a local of virExec() just prior to execve().

Since we will have another use for the full absolute path, lets make
an API to resolve/retrieve the absolute path, and cache it in
virCommand::binaryPath so we only have to do the resolution once.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-03-10 14:09:16 -05:00
Laine Stump a2929d4b38 NEWS: note new passt feature & bugfix for 9.1.0 release
This also adds a sentence pointing out that SELinux must be disabled
in order for passt support to work. I didn't think to put that info in
the NEWS file last month when reporting the addition of passt support.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2023-02-28 13:50:09 -05:00
Laine Stump f62ce81b8a qemu: respond to NETDEV_STREAM_DISCONNECTED event
When a QEMU netdev is of type "stream", if the socket it uses for
connectivity to the host network gets closed, then QEMU will send a
NETDEV_STREAM_DISCONNECTED event. We know that any stream netdev we've
created is backed by a passt process, and if the socket was closed,
that means the passt process has disappeared.

When we receive this event, we can respond by starting a new passt
process with the same options (including socket path) we originally
used. If we have previously created the stream netdev device with a
"reconnect" option, then QEMU will automatically reconnect to this new
passt process. (If we hadn't used "reconnect", then QEMU will never
try to reconnect to the new passt process, so there's no point in
starting it.)

Note that NETDEV_STREAM_DISCONNECTED is an event sent for the netdev
(ie "host side") of the network device, and so it sends the
"netdev-id" to specify which device was disconnected. But libvirt's
virDomainNetDef (the object used to keep track of network devices) is
the internal representation of both the host-side "netdev", and the
guest side device, and virDomainNetDef doesn't directly keep track of
the netdev-id, only of the device's "alias" (which is the "id"
parameter of the *guest* side of the device). Fortunately, by convention
libvirt always names the host-side of devices as "host" + alias, so in
order to search for the affected NetDef, all we need to do is trim the
1st 4 characters from the netdev-id and look for the NetDef having
that resulting trimmed string as its alias. (Contrast this to
NIC_RX_FILTER_CHANGED, which is an event received for the guest side
of the device, and so directly contains the device alias.)

Resolves: https://bugzilla.redhat.com/2172098
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-02-22 08:36:13 -05:00
Laine Stump acd8333f76 qemu: add reconnect=5 to passt qemu commandline options when available
QEMU's "reconnect" option of "-netdev stream" tells QEMU to
periodically (period is given in seconds as an argument to the option)
attempt to reconnect to the same passt socket to which it had
originally connected to. This is useful in cases where the passt
process terminates, and libvirtd starts a new passt process in its
place (which doesn't happen yet, but will happen automatically after
an upcoming patch in this series).

Since there is no real hueristic for determining the "best" value of
the reconnect interval, rather than clutter up config with a knob that
nobody knows how to properly twiddle, we just set the reconnect timer
to 5 seconds.

"-netdev stream" first appeared in QEMU 7.2.0, but the reconnect
option won't be available until QEMU 8.0.0, so we need to check QEMU
capabilities just in case someone is using QEMU 7.2.0 (and thus can
support passt backend, but not reconnect)

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-02-22 08:26:01 -05:00
Laine Stump 771992363e qemu: remove extraneous error log when qemuPasstStart() fails during hotplug
qemuPasstStart() already logs any error that occurs, so having the
caller log a generic error message only serves to obscure the actual
problem.

Fixes: a56f0168d5
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-02-22 08:21:48 -05:00
Laine Stump dffc40db69 qemu: add check for QEMU_CAPS_NETDEV_STREAM during validation
In commit 5af6134e I had added a new capability that is true if QEMU
allows "-netdev stream", but somehow neglected to actually check it in
commit a56f0168d when hooking up passt support to qemu. This isn't
catastrophic, since QEMU itself will still report an error, but that
error isn't as easy to understand as a libvirt-generated error.

Fixes: a56f0168d5
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-02-22 07:36:45 -05:00
Laine Stump 110d209263 qemu: forbid updating any attributes of an interface <backend> with update-device
Changing any of the attributes of an <interface>'s <backend> would
require removing and re-adding the interface for the new setting to
take effect, so fail any update-device that changes anything in
<backend>

Resolves: https://bugzilla.redhat.com/2169245
Signed-off-by: Laine Stump <laine@redhat.com>
2023-02-21 14:44:54 -05:00
Laine Stump 0c4e716835 qemu: allow passt to self-daemonize
I initially had the passt process being started in an identical
fashion to the slirp-helper - libvirt was daemonizing the new process
and recording its pid in a pidfile. The problem with this is that,
since it is daemonized immediately, any startup error in passt happens
after the daemonization, and thus isn't seen by libvirt - libvirt
believes that the process has started successfully and continues on
its merry way. The result was that sometimes a guest would be started,
but there would be no passt process for qemu to use for network
traffic.

Instead, we should be starting passt in the same manner we start
dnsmasq - we just exec it as normal (along with a request that passt
create the pidfile, which is just another option on the passt
commandline) and wait for the child process to exit; passt then has a
chance to parse its commandline and complete all the setup prior to
daemonizing itself; if it encounters an error and exits with a non-0
code, libvirt will see the code and know about the failure. We can
then grab the output from stderr, log that so the "user" has some idea
of what went wrong, and then fail the guest startup.

Signed-off-by: Laine Stump <laine@redhat.com>
2023-02-09 11:23:04 +01:00
Laine Stump 7b5777afcb docs: fix passt example
Somehow the example I neglected to fully update the example for the
interface passt backend when the design changed during
development. This fixes the example to reflect what is in the code.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-01-23 11:43:32 -05:00
Laine Stump 6ce7cebea3 tests: remove unused qemu .args file
net-user-passt.args was generated early during testing of the passt
qemu commandline, when qemuxml2argvtest was using
DO_TEST("net-user-passt"). This was later changed to
DO_TEST_CAPS_LATEST(), so the file net-user-passt.x86_64-latest.args
is used instead, but the original (now unused) test file was
accidentally added to the original patch. This patch removes it.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
2023-01-13 10:02:05 +01:00
Laine Stump a2042a4516 qemu: remove commented-out option in passt qemu commandline setup
This commented-out option was pointed out by jtomko during review, but
I missed taking it out when addressing his comments.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
2023-01-13 10:02:05 +01:00
Laine Stump 3592b81c4c conf: remove <backend upstream='xxx'/> attribute
This attribute was added to support setting the --interface option for
passt, but in a post-push/pre-9.0-release review, danpb pointed out
that it would be better to use the existing <source dev='xxx'/>
attribute to set --interface rather than creating a new attribute (in
the wrong place). So we remove backend/upstream, and change the passt
commandline creation to grab the name for --interface from source/dev.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
2023-01-13 10:02:05 +01:00
Laine Stump a5738ab74c NEWS: document addition of passt support
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
2023-01-10 10:37:10 -05:00
Laine Stump b6e72716c9 specfile: require passt for the build if fedora >= 36 or rhel >= 9
The only reason we need it at build time is to find its location in
$PATH so it can be hardcoded into the libvirt binary (and avoid the
possibility of someone adding in a malicious binary somewhere earlier
in the path, I guess).

Only 'recommend' passt during installation though, since it is not
needed unless someone is actually using it.

There is no need to add in a build-time "WITH_PASST" option (IMO),
since it adds very little to the size of the code - "PASST" (the path
to the binary) will just be set to "passt", so if someone does manage
to build and install passt on an older version of Fedora or RHEL, it
will still work (as long as it's installed somewhere in the path).

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-01-10 01:19:27 -05:00
Laine Stump a56f0168d5 qemu: hook up passt config to qemu domains
This consists of (1) adding the necessary args to the qemu commandline
netdev option, and (2) starting a passt process prior to starting
qemu, and making sure that it is terminated when it's no longer
needed. Under normal circumstances, passt will terminate itself as
soon as qemu closes its socket, but in case of some error where qemu
is never started, or fails to startup completely, we need to terminate
passt manually.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-01-10 01:19:25 -05:00
Laine Stump 98a24813c8 qemu: add passtStateDir to qemu driver config
...following in the patter of slirpStateDir.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-01-09 14:24:27 -05:00
Laine Stump 5af6134e70 qemu: new capability QEMU_CAPS_NETDEV_STREAM
passt support requires "-netdev stream", which was added to QEMU in
qemu-7.2.0.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-01-09 14:24:27 -05:00
Laine Stump a8ee7ae301 conf: parse/format passt-related XML additions
This implements XML config to represent a subset of the features
supported by 'passt' (https://passt.top), which is an alternative
backend for emulated network devices that requires no elevated
privileges (similar to slirp, but "better").

Along with setting the backend to use passt (via <backend
type='passt'/> when the interface type='user'), we also support
passt's --log-file and --interface options (via the <backend>
subelement logFile and upstream attributes) and its --tcp-ports and
--udp-ports options (which selectively forward incoming connections to
the host on to the guest) via the new <portForward> subelement of
<interface>. Here is an example of the config for a network interface
that uses passt to connect:

    <interface type='user'>
      <mac address='52:54:00:a8:33:fc'/>
      <ip address='192.168.221.122' family='ipv4'/>
      <model type='virtio'/>
      <backend type='passt' logFile='/tmp/xyzzy.log' upstream='eth0'/>
      <portForward address='10.0.0.1' proto='tcp' dev='eth0'>
        <range start='2022' to='22'/>
        <range start='5000' end='5099' to='1000'/>
        <range start='5010' end='5029' exclude='yes'/>
      </portForward>
      <portForward proto='udp'>
        <range start='10101'/>
      </portForward>
    </interface>

In this case:

* the guest will be offered address 192.168.221.122 for its interface
  via DHCP

* the passt process will write all log messages to /tmp/xyzzy.log

* routes to the outside for the guest will be derived from the
  addresses and routes associated with the host interface "eth0".

* incoming tcp port 2022 to the host will be forwarded to port 22
  on the guest.

* incoming tcp ports 5000-5099 (with the exception of ports 5010-5029)
  to the host will be forwarded to port 1000-1099 on the guest.

* incoming udp packets on port 10101 will be forwarded (unchanged) to
  the guest.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-01-09 14:24:27 -05:00
Laine Stump 63fbe529fc conf: add passt XML additions to schema
Initial support for network devices using passt (https://passt.top)
for the backend connection will require:

* new attributes of the <backend> subelement:
  * "type" that can have the value "passt" (to differentiate from
    slirp, because both slirp and passt will use <interface
    type='user'>)
  * "logFile" (a path to a file that passt should use for its logging)
  * "upstream" (a netdev name, e.g. "eth0").

* a new subelement <portForward> (described in more detail later)

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-01-09 14:24:27 -05:00
Laine Stump efd286a760 conf: put interface <backend> parsing/formatting separate functions
In preparation for adding more stuff to <backend>.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-01-09 14:24:27 -05:00
Laine Stump 7f6bb51eb9 conf: move anonymous backend struct from virDomainNetDef into its own struct
This will allow us to call parser/formatter functions with a pointer
to just the backend part.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-01-09 14:24:27 -05:00
Laine Stump d3307a8fd2 conf: rename virDomainNetBackend* to virDomainNetDriver*
This fits better with the element containing the value (<driver>), and
allows us to use virDomainNetBackend* for things in the <backend>
element.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-01-09 14:24:27 -05:00
Laine Stump 4c0310677a util: don't use virFirewallRuleToString() to log the rule being applied
Instead of separately building the commandline into a string to log,
just wait a few lines until we've built the virCommand object, and
call virCommandToString, which does the same thing.

(As a bonus, we were already calling virCommandToString to put the
commandline in a string in case of a failure when running it - from
the point of view of *that* usage, we're just moving the call to
virCommandToString *up* a few lines, i.e. we now only construct the
commandline string once.)

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:47 -04:00
Laine Stump 4dce6eee5c util: make virFirewallRuleToString() global
Although the next commit will eliminate the one current use of
virFirewallRuleToString(), a future commit will once again have a use
for it, but in a different source file so it will need to be a global
function rather than static. Make that change now so that we don't get
a compile error from having an unused static function in the next
commit.

(The arg list is also changed to include the name of the command as a
separate argument rather than just assuming that it can be derived
from the rule's layer (which is correct for iptables, but won't be
correct for nftables)).

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:47 -04:00
Laine Stump 2d1c22a015 util: remove unused function virFirewallApplyRuleFirewallD()
This was a wrapper to call a function in virfirewalld.c that sends an
iptables passthrough rule to firewalld. It hasn't been used in a year
or two, and won't ever be used in the future since passthrough rules
are only supported for iptables, and we've determined that we
shouldn't use iptables passthrough rules.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:47 -04:00
Laine Stump cd23bf182c util: replace g_snprintf with g_autofreed g_strdup_printf in viriptables.c
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:47 -04:00
Laine Stump b7b949d30c network: create separate config object for virNetworkDriverState
Similar to the other drivers, virNetworkDriverState now has a
virObject-derived object called virNetworkDriverConfig which is used
for config items.

As a starting point, the directory paths used by the network driver
are moved there (again, parallelling what is done for other drivers).

Using items in virNetworkDriverConfig is (yes, again) similar to using
items in the other drivers' config - anything in the config object is
immutable (once initialized), so the state object only needs to be
locked while getting a reference to the config object, and then the
members of the config object can be safely used until the config
object is unrefed.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:47 -04:00
Laine Stump 3fcae3c6d4 network: move driver state struct into bridge_driver_conf.h
This is more similar to lxc and qemu drivers, where the driver state
struct is defined along with a config struct in ${driver}_conf.h

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:47 -04:00
Laine Stump 15bd9179be tests: remove superfluous cleanup: labels and ret return variables
After converting virNetworkDef * to g_autoptr(virNetworkDef) the
cleanup codepath was empty, so it has been removed.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:47 -04:00
Laine Stump 9a64c66d34 qemu: remove superfluous cleanup: labels and ret return variables
After converting virNetworkDef * to g_autoptr(virNetworkDef) the
cleanup codepath was empty, so it has been removed.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:47 -04:00
Laine Stump 658cbbea5c conf: remove superfluous cleanup: labels and ret return variables
After converting virNetworkDef * to g_autoptr(virNetworkDef) the
cleanup codepath was empty, so it has been removed.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:47 -04:00
Laine Stump d9074b8e01 tests: replace explicit virNetworkDefFree() with g_autoptr(virNetworkDef)
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:47 -04:00
Laine Stump 8e71e5b10e vbox: replace explicit virNetworkDefFree() with g_autoptr(virNetworkDef)
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:47 -04:00
Laine Stump 7f0978843f test driver: replace explicit virNetworkDefFree() with g_autoptr(virNetworkDef)
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:47 -04:00
Laine Stump 175d8a0852 qemu: replace explicit virNetworkDefFree() with g_autoptr(virNetworkDef)
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:46 -04:00
Laine Stump bea8da6b12 network: replace explicit virNetworkDefFree() with g_autoptr(virNetworkDef)
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:46 -04:00
Laine Stump 635be49d81 esx: replace explicit virNetworkDefFree() with g_autoptr(virNetworkDef)
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:46 -04:00
Laine Stump f172de14fe conf: replace explicit virNetworkDefFree() with g_autoptr(virNetworkDef)
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-08-24 12:22:46 -04:00
Laine Stump 640d185f01 qemu: don't call qemuMigrationSrcIsAllowedHostdev() from qemuMigrationDstPrepareFresh()
This call to qemuMigrationSrcIsAllowedHostdev() (which does a
hardcoded fail of the migration if there is any PCI or mdev hostdev
device in the domain) while doing the destination side of migration
prep was found once the call to that same function was removed from
the source side migration prep (commit 25883cd5).

According to jdenemar, for the V2 migration protocol, prep of the
destination is the first step, so this *was* the proper place to do
the check, but for V3 migration this is in a way redundant (since we
will have already done the check on the source side (updated by
25883cd5 to query QEMU rather than do a hardcoded fail)).

Of course it's possible that the source could support migration of a
particular VFIO device, but the destination doesn't. But the current
check on the destination side is worthless even in that case, since it
is just *always* failing rather than querying QEMU; and QEMU can't be
queried at the point where the destination check is happening, since
it isn't yet running.

Anyway QEMU should complain when it's started if it's going to fail,
so removing this check should just move the failure to happen a bit
later. So the best solution to this problem is to simply remove the
hardcoded check/fail from qemuMigrationDstPrepareFresh() and rely on
QEMU to fail if it needs to.

Fixes: 25883cd5f0
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
2022-07-28 08:16:29 -04:00
Laine Stump 25883cd5f0 qemu: skip hardcoded hostdev migration check if QEMU can do it for us
libvirt currently will block migration for any vfio-assigned device
unless it is a network device that is associated with a virtio-net
failover device (ie. if the hostdev object has a teaming->type ==
VIR_DOMAIN_NET_TEAMING_TYPE_TRANSIENT).

In the future there will be other vfio devices that can be migrated,
so we don't want to rely on this hardcoded block. QEMU 6.0+ will
anyway inform us of any devices that will block migration (as a part
of qemuDomainGetMigrationBlockers()), so we only need to do the
hardcoded check in the case of old QEMU that can't provide that
information.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
2022-07-21 11:12:46 -04:00
Laine Stump 2dd5587f1d qemu: don't try to query QEMU about migration blockers during offline migration
The new code that queries QEMU about migration blockers was put at the
top of qemuMigrationSrcIsAllowed(), but that function can also be
called in the case of offline migration (ie when the domain is
inactive / QEMU isn't running). This check should have been put inside
the "if (!(flags & VIR_MIGRATE_OFFLINE))" conditional, so let's move
it there.

Fixes: 156e99f686
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
2022-07-21 11:12:44 -04:00
Laine Stump 497e6f5fa6 util: remove virFirewallOnceInit()
There is no longer anything to initialize at binary startup time.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2021-12-13 13:37:31 -05:00
Laine Stump d566cc55bf util: remove currentBackend from virfirewall.c
Since the currentBackend (direct vs. firewalld) setting is no longer
used for anything, we don't need to set it (either explicitly from
tests, or implicitly during init), and can completely remove it.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2021-12-13 13:37:31 -05:00