Add a "allow_special" parameter to get_node_canonicalized() allowing
to merge get_spec_node() into get_node_canonicalized().
Add the same parameter to is_valid_nodename(), as this will simplify
check_watch_path().
This is done in preparation to introducing a get_node() variant
returning a pointer to const struct node.
Note that this will change how special node names are going to be
validated, as now the normal restrictions for node names will be
applied:
- they can't end with "/"
- they can't contain "//"
- they can't contain characters other than the ones allowed for normal
nodes
- the length of the node name is restricted by the max path length
quota
For defined special node names this isn't any real restriction, though.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Introduce a read_node() variant returning a pointer to const struct
node, which doesn't do a copy of the node data after retrieval from
the data base.
Call this variant where appropriate.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
In order to avoid modifying the node data in the data base in case a
domain is gone, let domain_adjust_node_perms() allocate new memory for
the permissions in case they need to be modified. As this should
happen only in very rare cases, it is fine to do this even when having
copied the node data already.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Replace some individual fields in struct node with struct node_hdr.
This allows to add a helper for calculating the accounted memory size
of a node.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Open code struct node_perms in struct node in order to prepare using
struct node_hdr in struct node.
Add two helpers to transfer permissions between struct node and struct
node_perms and a helper to directly get connection base permissions
from a node.
Let perms_to_strings() take a struct node as parameter and rename it
to node_perms_to_strings().
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Struct xs_tdb_record_hdr is used for nodes stored in the data base.
When working on a node, struct node is being used, which is including
the same information as struct xs_tdb_record_hdr, but in a different
format. Rework struct xs_tdb_record_hdr in order to prepare including
it in struct node.
Do the following modifications:
- move its definition to xenstored_core.h, as the reason to put it into
utils.h are no longer existing
- rename it to struct node_hdr, as the "tdb" in its name has only
historical reasons
- replace the empty permission array at the end with a comment about
the layout of data in the data base (concatenation of header,
permissions, node contents, and children list)
- use narrower types for num_perms and datalen, as those are naturally
limited to XENSTORE_PAYLOAD_MAX (childlen is different here, as it is
in theory basically unlimited)
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Today the node data is copied in db_fetch() on each data base read in
order to avoid accidental data base modifications when working on a
node.
read_node() is the only caller of db_fetch() which isn't freeing the
returned data area immediately after using it. The other callers don't
modify the returned data, so they don't need the data to be copied.
Move copying of the data into read_node(), resulting in a speedup of
the other callers due to no memory allocation and no copying being
needed anymore.
This allows to let db_fetch() return a pointer to const data.
As db_fetch() can't return any error other than ENOENT now, error
handling for the callers can be simplified.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
With talloc_free() and related functions not taking a pointer to const
it is tedious to use the const attribute for talloc()-ed memory in
many cases.
Change the related prototypes to use "const void *" instead of
"void *".
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
db_delete() only ever is returning 0. Switch it to return void and
remove all the error handling dealing wit a non-zero return value.
Suggested-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Today all Xenstore nodes are stored in a TDB data base. This data base
has several disadvantages:
- It is using a fixed sized hash table, resulting in high memory
overhead for small installations with only very few VMs, and a rather
large performance hit for systems with lots of VMs due to many
collisions.
The hash table size today is 7919 entries. This means that e.g. in
case of a simple desktop use case with 2 or 3 VMs probably far less
than 10% of the entries will be used (assuming roughly 100 nodes per
VM). OTOH a setup on a large server with 500 VMs would result in
heavy conflicts in the hash list with 5-10 nodes per hash table entry.
- TDB is using a single large memory area for storing the nodes. It
only ever increases this area and will never shrink it afterwards.
This will result in more memory usage than necessary after a peak of
Xenstore usage.
- Xenstore is only single-threaded, while TDB is designed to be fit
for multi-threaded use cases, resulting in much higher code
complexity than needed.
- Special use cases of Xenstore are not possible to implement with TDB
in an effective way, while an implementation of a data base tailored
for Xenstore could simplify some handling (e.g. transactions) a lot.
So drop using TDB and store the nodes directly in memory making them
easily accessible. Use a hash-based lookup mechanism for fast lookup
of nodes by their full path.
For now only replace TDB keeping the current access functions.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
For an effective way to replace a hashtable entry add a new function
hashtable_replace().
This is in preparation to replace TDB with a more simple data storage.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Julien Grall <jgrall@amazon.com>
Silently adding another entry with the same key to a hashtable is a
perfect receipt for later failure with hard to diagnose symptoms.
Let hashtable_add() fail in case another entry with the same key is
already existing.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
The key is never modified by hashtable code, so it should be marked as
const.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
The "cpuid_empty" label is also (in principle; maybe only for rubbish
input) reachable in the "cpuid_only" case. Hence the label needs to live
ahead of the check of the variable.
Fixes: 5b80cecb74 ("libxl: introduce MSR data in libxl_cpuid_policy")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
In case Xen has been configured with "--disable-pygrub", don't accept
the domain config option "bootloader=pygrub".
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
The only in-tree user of libfsimage is pygrub. Now that it is possible
to disable the build of pygrub, the same should be possible for
libfsimage.
Add an option for controlling the build of libfsimage. The default is
on if pygrub is being built, and off if it isn't. Without pygrub the
build of libfsimage can be enabled via --enable-libfsimage.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Add a "--disable-pygrub" option for being able to disable the build
and installation of pygrub.
There are two main reasons to do so:
- A main reason to use pygrub is to allow a PV guest to choose its
bitness (32- or 64-bit). Pygrub allows that by looking into the boot
image and to start the guest in the correct mode depending on the
kernel selected. With 32-bit PV guests being deprecated and the
possibility to even build a hypervisor without 32-bit PV support,
this use case is gone for at least some configurations.
- Pygrub is running in dom0 with root privileges. As it is operating
on guest controlled data (the boot image) and taking decisions based
on this data, there is a higher security risk. Not being possible
to use pygrub is thus a step towards a reduction of attack surface.
Default is still to build and install pygrub.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
While what "tmp" points to has been cleared at the end of the first
iteration of parseNetDevLine()'s main loop, this is too late for the
first iteration's invocation of strpbrk() (copying the interface name).
Properly nul-terminate the string at population time instead, removing
the late clearing.
While there also eliminate a confusing (because of being wrong) comment:
A regex parsing error would be handled one further scope outwards. Here
we're dealing with field 1 vs any of the later fields.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
GDS_CTRL is introduced by the August 2023 microcode. GDS_NO is for current
and future processors not susceptible to GDS.
This is part of XSA-435 / CVE-2022-40982
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
AMD have specified new CPUID bits relating to SRSO.
* SRSO_NO indicates that hardware is no longer vulnerable to SRSO.
* IBPB_BRTYPE indicates that IBPB flushes branch type information too.
* SBPB indicates support for a relaxed form of IBPB that does not flush
branch type information.
Current CPUs (Zen4 and older) are not expected to enumerate these bits.
Native software is expected to synthesise them for guests using model and
microcode revision checks.
Two are just status bits, and SBPB is trivial to support for guests by
tweaking the reserved bit calculation in guest_wrmsr() and feature
dependencies. Expose all by default to guests, so they start showing up when
Xen synthesises them.
While adding feature dependenies for IBPB, fix up an overlooked issue from
XSA-422. It's inappropriate to advertise that IBPB flushes RET predictions if
IBPB is unavailable itself.
This is part of XSA-434 / CVE-2023-20569
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
In osstest, the jobs using pygrub on arm64 on the branch linux-linus
started to fails with:
[Errno 28] No space left on device
Error writing temporary copy of ramdisk
This is because /var/run is small when dom0 has only 512MB to work
with, /var/run is only 40MB. The size of both kernel and ramdisk on
this jobs is now about 42MB, so not enough space in /var/run.
So, to avoid writing a big binary in ramfs, we will use /var/lib
instead, like we already do when saving the device model state on
migration.
Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
We can't use initializers of unnamed struct/union members just yet.
Fixes: d638fe233c ("libxl: use the cpuid feature names from cpufeatureset.h")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Because of -Wshadow the build otherwise fails with old enough glibc.
While there also obey line length limits for msr_add().
Fixes: 6d21cedbaa ("libxl: add support for parsing MSR features")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Add -e argument to xl console and pass to new escape_character argument
of libxl_console_exec.
Introduce a new API version to support this new argument and advertise
the new functionality in libxl.h
In libxl_console_exec, there are currently two call sites to execl,
which uses varargs, in order to support optionally passing
'start-notify-fd' to the console client. In order to support passing
the 'escape' argument optionally too, refactor to instead have a single
call site to execv, which has the same behavior but takes an array of
arguments.
If -e is not specified, --escape is not passed to the console client and
the existing value (^]) is used as a default.
Update the xl docs.
Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
These defines are not used by xenalyze.
NR_CPUS will not match what was used for building Xen itself.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Reviewed-by: George Dunlap <george.dunlap@cloud.com>
Invoking the --help option of any tool should not return with an error,
if that tool does have a documented and implemented help option.
Adjust the usage() function to exit with either error or success.
Handle the existing entry in the option table to call usage accordingly.
Adjust the getopt value for help. The char '?' is returned for unknown
options. Returning 'h' instead of '?' allows to handle --help.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Reviewed-by: George Dunlap <george.dunlap@cloud.com>
Without it being present it won't be possible to use some
libxl__device_type's callbacks for virtio devices as the common code
can only invoke these callbacks (by dereferencing a pointer) for valid
libxl__device_type's elements when iterating over device_type_tbl[].
Please note, there is no issue within current the code base as virtio
devices don't use callbacks that depend on libxl__virtio_devtype
presence in device_type_tbl[]. The issue will appear as soon as we start
using these callbacks (for example, dm_needed).
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Add a wrapper function for tdb_fetch taking the name of the node in
the data base as a parameter. Let it return a data pointer and the
length of the data via a length pointer provided as additional
parameter.
Move logging of the TDB access from the callers into the wrapper.
This enables to make set_tdb_key() and tdb_ctx static.
This is in preparation to replace TDB with a more simple data storage.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Eliminate further TDB_DATA usage by switching get_acc_data() and
get_acc_domid() from a TDB key to the name of the node in the data base
as a parameter.
This is in preparation to replace TDB with a more simple data storage.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Rename do_tdb_write() to db_write() and replace the key parameter with
db_name specifying the name of the node in the data base, and the data
parameter with a data pointer and a length.
Do the same key parameter type change for write_node_raw(), too.
This is in preparation to replace TDB with a more simple data storage.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Rename do_tdb_delete() to db_delete() and replace the key parameter
with db_name specifying the name of the node in the data base.
This is in preparation to replace TDB with a more simple data storage.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Instead of setting the TDB key for accessing the node in the data base,
let transaction_prepend() return the associated name instead.
This is in preparation to replace TDB with a more simple data storage.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Instead of storing the TDB key in struct node, only store the name of
the node used to access it in the data base.
Associated with that change replace the key parameter of access_node()
with the equivalent db_name.
This is in preparation to replace TDB with a more simple data storage.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Instead of using TDB_REPLACE for either creating or modifying a TDB
entry, use either TDB_INSERT or TDB_MODIFY when calling tdb_store().
At higher function levels use the abstract mode values NODE_CREATE
and NODE_MODIFY.
This is for preparing to get rid of TDB, even if it is beneficial
while using TDB, too.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
In case get_spec_node() is being called for a special node starting
with '@' it won't set *canonical_name. This can result in a crash of
xenstored due to dereferencing the uninitialized name in
fire_watches().
This is no security issue as it requires either a privileged caller or
ownership of the special node in question by an unprivileged caller
(which is questionable, as this would make the owner privileged in some
way).
Fixes: d6bb63924f ("tools/xenstore: introduce dummy nodes for special watch paths")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
The return type of canonicalize() can be modified to const char *.
This avoids the need to cast the const away from the input parameter.
There need to be quite some other functions modified to take const
parameters in order to avoid further casts.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Dom0 may be accessed via telnet, meaning the default escape character
(which is the same as telnet's) cannot be directly used to exit the
console. It would be helpful to make the escape character customizable
in such use cases.
Add --escape argument to console tool for this purpose.
Add argument to getopt options, parse and validate the escape character
and pass value to console_loop.
If --escape is not specified, it falls back to the existing behavior
using DEFAULT_ESCAPE_SEQUENCE.
Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Hongda Deng <hongda.deng@arm.com>
Introduce support for handling MSR features in
libxl_cpuid_parse_config(). The MSR policies are added to the
libxl_cpuid_policy like the CPUID one, which gets passed to
xc_cpuid_apply_policy().
This allows existing users of libxl to provide MSR related features as
key=value pairs to libxl_cpuid_parse_config() without requiring the
usage of a different API.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
The current implementation in libxl_cpuid_parse_config() requires
keeping a list of cpuid feature bits that should be mostly in sync
with the contents of cpufeatureset.h.
Avoid such duplication by using the automatically generated list of
cpuid features in INIT_FEATURE_NAMES in order to map feature names to
featureset bits, and then translate from featureset bits into cpuid
leaf, subleaf, register tuple.
Note that the full contents of the previous cpuid translation table
can't be removed. That's because some feature names allowed by libxl
are not described in the featuresets, or because naming has diverged
and the previous nomenclature is preserved for compatibility reasons.
Should result in no functional change observed by callers, albeit some
new cpuid features will be available as a result of the change.
While there constify cpuid_flags name field.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Move the CPUID value parsers out of libxl_cpuid_parse_config() into a
newly created cpuid_add() local helper. This is in preparation for
also adding MSR feature parsing support.
No functional change intended.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Add a new array field to libxl_cpuid_policy in order to store the MSR
policies.
Adding the MSR data in the libxl_cpuid_policy_list type is done so
that existing users can seamlessly pass MSR features as part of the
CPUID data, without requiring the introduction of a separate
domain_build_info field, and a new set of handlers functions.
Note that support for parsing the old JSON format is kept, as that's
required in order to restore domains or received migrations from
previous tool versions. Differentiation between the old and the new
formats is done based on whether the contents of the 'cpuid' field is
an array or a map JSON object.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Currently libxl_cpuid_policy_list is an opaque type to the users of
libxl, and internally it's an array of xc_xend_cpuid objects.
Change the type to instead be a structure that contains one array for
CPUID policies, in preparation for it also holding another array for
MSR policies.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Like it's done with CPUID, introduce support for passing MSR values to
xc_cpuid_apply_policy(). The chosen format for expressing MSR policy
data matches the current one used for CPUID. Note that existing
callers of xc_cpuid_apply_policy() can pass NULL as the value for the
newly introduced 'msr' parameter in order to preserve the same
functionality, and in fact that's done in libxl on this patch.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Juergen Gross
Jens Wiklander
Jan Beulich
Andrew Cooper
Anthony PERARD
Peter Hoyes
Olaf Hering
Oleksandr Tyshchenko
Roger Pau Monne