64-bit BAR memory address is truncated when removing a passthrough
pci device from guest since it uses "unsigned int".
So, change to use 64-bit type to fix this problem.
This is XSA-476 / CVE-2025-58149.
Fixes: b0a1af6167 ("libxenlight: implement pci passthrough")
Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
Release-Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>
removeprefix is only added in Python 3.9.
Instead of the prefix removal, switch to passing in a "depth" parameter,
and incrementing it for each level.
There is a slight change in the generated _libxl_types.c. instances of
KeyedUnion increment depth without outputing any code. The net result
is some cases where jso_sub_1 is followed by jso_sub_3. As an example:
_libxl_types.c
_libxl_types.c
@@ -5535,12 +5535,12 @@
if (!jso_sub_1)
goto out;
if (!libxl__string_is_default(&p->u.pty.path)) {
- json_object *jso_sub_2 = NULL;
- rc = libxl__string_gen_jso(&jso_sub_2, p->u.pty.path);
+ json_object *jso_sub_3 = NULL;
+ rc = libxl__string_gen_jso(&jso_sub_3, p->u.pty.path);
if (rc)
goto out;
- if (json_object_object_add(jso_sub_1, "path", jso_sub_2)) {
- json_object_put(jso_sub_2);
+ if (json_object_object_add(jso_sub_1, "path", jso_sub_3)) {
+ json_object_put(jso_sub_3);
goto out;
}
}
Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
It's possible for libxl__json_object_to_json_object() to not set the passed
jso_out parameter, hence initialize it in libxl__json_object_to_json() to
avoid freeing an uninitialized pointer in case of failure.
Reported by XenServer internal Coverity instance.
Fixes: 75fa670e58 ("libxl: Convert libxl__json_object_to_json() to json_object")
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
Release-Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
It's possible for json_tokener_parse_verbose() to return NULL and leave the
error parameter unset. Initialize the error variable at definition to an
existing error token to make sure it's not uninitialized in case of
failure.
Reported by XenServer internal Coverity instance.
Fixes: 7e95dab9eb ("libxl: Convert libxl__json_parse() to use json-c")
Fixes: f6c6f2679d ("libxl: Convert libxl__object_to_json() to json-c")
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
- libxl changes:
While doing so, we rename all "*_gen_json" function to "*_gen_jso" as
they have different prototype. All the function pointer are been cast
to (libxl__gen_json_callback) by "gentypes.py" when generating
"*_to_json()" functions.
We also introduce a few more "*_gen_jso" functions for "int" and
"bool" because we can't use json_object_*() functions from json-c
directly like it's done with yajl.
To make the generation of _libxl_types*json.[ch] with both YAJL and
json-c we add "--libjsonc" to gentypes.py so it can generate
functions/types for both.
Also introducing "jsonc_json_gen_fn" in the IDL, to be able to point
to a different function when using json-c.
Also, don't export any of the new *_gen_jso() function, at the cost of
having "_hidden" macro in semi-public headers.
- xl changes:
Also, rework the implementation of printf_info() in `xl` to avoid
using libxl_domain_config_gen_json() which isn't available without
YAJL. The implementation using "json_object" call
libxl_domain_config_to_json() which generate a plain string of JSON,
which we parse to add it to our own json; this avoid a dependency on
the json library used by libxl.
Signed-off-by: Anthony PERARD <anthony.perard@vates.tech>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
Convert yajl_gen to json_object from lib json-c.
And make use of it in qmp_prepare_cmd(), which can be compiled with
either lib.
Signed-off-by: Anthony PERARD <anthony.perard@vates.tech>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
This reuse the "json_callback_*" implemented for the yajl parser as
they don't really need to be changed. It's just awkward to have to
cast between `unsigned char` and `char.`
Replace few strncpy() by memcpy() to let the compiler know we want to
copy the string without the terminating nul, as we are adding it just
after.
Also, it should be possible to keep using YAJL parser when json-c
library isn't available.
Signed-off-by: Anthony PERARD <anthony.perard@vates.tech>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
To replace yajl.
Introduce XEN_JSON_LIBS variable, to be able to remove "-lyajl" later.
As a first step, the variable will have both or only -lyajl. Then
commit "configure: Use json-c by default, fallback to yajl" will make
a change to only have one or the other once the code is ready to build
with only json-c.
Signed-off-by: Anthony PERARD <anthony.perard@vates.tech>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
Callers observing errors elsewhere may be confused by the ENOSYS that
the Flask operation would yield on a Flask-disabled hypervisor.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>
Dom0 is never started in PoD mode, and hence it can at "best" do harm if
we try to set a PoD target for it.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>
The commit 3e322bef8b ("xen/arm: firmware: Add SCMI over SMC calls
handling layer") introduces simple driver which forwards SCMI over SMC
calls from hwdom/dom0 to EL3 firmware (TF-A) with a single SCMI OSPM agent
support. While it is working gracefully for hwdom/dom0 use case it doesn't
cover "thin Dom0 with guest domain, which serves as Driver domain"
use-case. In this case HW need to be enable in Driver domain and dom0 is
performing only control functions.
The EL3 SCMI firmware (TF-A) with a single SCMI OSPM agent support is
pretty generic case for the default vendors SDK and new platforms.
This patch enables passthrough of SCMI SMC single agent interface to the
one guest domain serving as Driver domain.
Configure Dom0 to enable SCMI passthrough:
- dom0: add scmi-smc-passthrough to the Xen Command Line
Enabled SCMI passthrough for guest using toolstack in the following way:
- domD: xl.cfg add "arm_sci" option as below
arm_sci = "type=scmi_smc"
- domD: xl.cfg enable access to the "arm,scmi-shmem"
iomem = [
"47ff0,1@22001",
]
- domD: add SCMI nodes to the Driver domain partial device tree as in the
below example:
passthrough {
scmi_shm_0: sram@22001000 {
compatible = "arm,scmi-shmem";
reg = <0x0 0x22001000 0x0 0x1000>;
};
firmware {
compatible = "simple-bus";
scmi: scmi {
compatible = "arm,scmi-smc";
shmem = <&scmi_shm_0>;
...
}
}
}
dom0less case configuration:
- add "xen,sci_type" property for required DomU ("xen,domain") node
xen,sci_type="scmi_smc"
- add scmi nodes to the Driver domain partial device tree the same way
as above and enable access to the "arm,scmi-shmem" according to
dom0less documentation. For example:
scmi_shm_0: sram@22001000 {
compatible = "arm,scmi-shmem";
reg = <0x00 0x22001000 0x00 0x1000>;
-> xen,reg = <0x0 0x47ff0000 0x0 0x1000 0x0 0x22001000>;
-> xen,force-assign-without-iommu;
};
The SCMI SMC single agent interface can be enabled for one and only one
domain. In general, the configuration is similar to any other HW
passthrough, except explicitly enabling SCMI with "arm_sci" xl.cfg option.
Note that "arm,scmi-smc" and "arm,scmi-shmem" nodes will be removed from
dom0/hwdom DT when "scmi-smc-passthrough" cmdline parameter was provided.
Signed-off-by: Grygorii Strashko <grygorii_strashko@epam.com>
Signed-off-by: Oleksii Moisieiev <oleksii_moisieiev@epam.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech> # tools
This commit activates the previously introduced altp2m_count parameter,
establishing the connection between libxl and Xen.
Signed-off-by: Petr Beneš <w1benny@gmail.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>
Add a guest config parameter "xenstore_feature_mask" allowing to limit
the Xenstore features the guest can see and use. This can be needed in
order to allow migrating a guest to a host running a Xenstore version
providing less features than the source host.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
Acked-by: Nick Rosbrook <enr0n@ubuntu.com> # tools/golang
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
When removing qemu-trad support, libxl__domain_build_info_setdefault()
was modified to only allow qemu-xen as a device model. This change
resulted in an error at domain creation when qemu-xen isn't there.
As this is a perfectly fine situation for PV and PVH guests without
any qemu based backends, handle this case gracefully.
Fixes: 19ab8356ab ("tools: remove support for running a guest with qemu-traditional")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Hypercalls are not free; cache colouring is an experimental feature, and
ignoring an -EOPNOTSUPP is bad form.
Now that Xen has been fixed to initialise colouring information correctly for
domains, xc_domain_set_llc_colors() only needs calling for domains with
explicit configuration.
Rearrange the logic to avoid the hypercall in the general case, leaving a
comment explaining why it is performed so early.
Fixes: 748bd725fb ("tools: add support for cache coloring configuration")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Introduce a new altp2m_count parameter to control the maximum number of altp2m
views a domain can use. By default, if altp2m_count is unspecified and altp2m
is enabled, the value is set to 10, reflecting the legacy behavior.
This change is preparatory; it establishes the groundwork for the feature but
does not activate it.
Signed-off-by: Petr Beneš <w1benny@gmail.com>
Acked-by: Nick Rosbrook <enr0n@ubuntu.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Introduce a new altp2m_count parameter to control the maximum number of altp2m
views a domain can use. By default, if altp2m_count is unspecified and altp2m
is enabled, the value is set to 10, reflecting the legacy behavior.
This change is preparatory; it establishes the groundwork for the feature but
does not activate it.
Signed-off-by: Petr Beneš <w1benny@gmail.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Acked-by: Nick Rosbrook <enr0n@ubuntu.com>
Encapsulate the altp2m options within a struct. This change is preparatory
and sets the groundwork for introducing additional parameter in subsequent
commit.
Signed-off-by: Petr Beneš <w1benny@gmail.com>
Acked-by: Christian Lindig <christian.lindig@cloud.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>
Acked-by: Julien Grall <jgrall@amazon.com> # arm
Reviewed-by: Jan Beulich <jbeulich@suse.com> # hypervisor
The Xen platform PCI device (vendor ID 0x5853) exposed to x86 HVM guests
doesn't have the functionality of a traditional PCI device. The exposed
MMIO BAR is used by some guests (including Linux) as a safe place to map
foreign memory, including the grant table itself.
Traditionally BARs from devices have the uncacheable (UC) cache attribute
from the MTRR, to ensure correct functionality of such devices. hvmloader
mimics this behavior and sets the MTRR attributes of both the low and high
PCI MMIO windows (where BARs of PCI devices reside) as UC in MTRR.
This however causes performance issues for users of the Xen platform PCI
device BAR, as for the purposes of mapping remote memory there's no need to
use the UC attribute. On Intel systems this is worked around by using
iPAT, that allows the hypervisor to force the effective cache attribute of
a p2m entry regardless of the guest PAT value. AMD however doesn't have an
equivalent of iPAT, and guest PAT values are always considered.
Linux commit:
41925b105e34 xen: replace xen_remap() with memremap()
Attempted to mitigate this by forcing mappings of the grant-table to use
the write-back (WB) cache attribute. However Linux memremap() takes MTRRs
into account to calculate which PAT type to use, and seeing the MTRR cache
attribute for the region being UC the PAT also ends up as UC, regardless of
the caller having requested WB.
As a workaround to allow current Linux to map the grant-table as WB using
memremap() introduce an xl.cfg option (xen_platform_pci_bar_uc=0) that can
be used to select whether the Xen platform PCI device BAR will have the UC
attribute in MTRR. Such workaround in hvmloader should also be paired with
a fix for Linux so it attempts to change the MTRR of the Xen platform PCI
device BAR to WB by itself.
Overall, the long term solution would be to provide the guest with a safe
range in the guest physical address space where mappings to foreign pages
can be created.
Some vif throughput performance figures provided by Anthoine from a 8
vCPUs, 4GB of RAM HVM guest(s) running on AMD hardware:
Without this patch:
vm -> dom0: 1.1Gb/s
vm -> vm: 5.0Gb/s
With the patch:
vm -> dom0: 4.5Gb/s
vm -> vm: 7.0Gb/s
Reported-by: Anthoine Bourgeois <anthoine.bourgeois@vates.tech>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Oleksii Kurochko<oleksii.kurochko@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com> # hvmloader
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
When a device is passed through to a xl domU, the iomem ranges may
overlap with the extended regions. Remove iomem from extended regions.
Signed-off-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Add a per-domain way to optionally disable traps for accesses
to unmapped addresses.
The domain flag is general but it's only implemented for Arm for now.
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Remove the code in tools for running a guest with qemu-traditional.
This covers xl, libxl, libacpi, hvmloader and the related python and
go bindings.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Jan Beulich <jbeulich@suse.com> # hvmloader
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Only access the HVM union b_info->u.hvm on HVM guests. The union
access is not guarded, so this reads and sets the default even on
non-HVM guests. Usually this doesn't matter as PV and PVH unions are
smaller and zero-initialized, but the zero default will be re-written as
a -1 boolean. Generally, it could incorrectly set b_info->altp2m
through aliased data.
Fixes: 0291089f6e ("xen: enable altp2m at create domain domctl")
Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>
The PCI device irq is read with fscanf(%u). Switch the irq variable to
unsigned int to match.
Linux driver/pci/pci-sysfs.c:irq_show() uses %u to print the value.
However, unsigned int irq doesn't compile because of:
error: pointer targets in passing argument 4 of 'xc_physdev_map_pirq' differ in signedness [-Werror=pointer-sign]
Add int pirq to provide the desired type instead of re-using irq.
Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
A PCI device's irq field is an 8-bit number. A value of 0xff indicates
that the device IRQ is not connected. Additionally, the Linux ACPI code
can convert these 0xff values to IRQ_NOTCONNECTED(0x80000000) because
"0x80000000 is guaranteed to be outside the available range of
interrupts and easy to distinguish from other possible incorrect
values." When the hypercall to assign that IRQ fails, device
passthrough as a whole fails.
Add checking for a valid IRQ and skip the IRQ handling for PCI devices
outside that range. This allows for passthrough of devices without
legacy IRQs.
Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
`QEMU_XEN_PATH` will be configured as `qemu-system-i386` with no clue where, if
`--with-system-qemu` is set without giving a path (as matched in the case `yes`
but not `*`). However, the existence of the executable is checked by `access()`,
that will not look for anywhere in $PATH but the current directory. And since it
is possible for `qemu-system-i386` (or any other configured values) to be
executed from PATH later, we'd better find that in PATH and return the full path
for the caller to check against.
Signed-off-by: Hongbo <hehongbo@mail.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
[Initialise `saveptr` to NULL]
Signed-off-by: Anthony PERARD <anthony.perard@vates.tech>
Now that common-macros.h has STR() available, which is even slightly
more flexible, use that and drop the custom macros.
No difference in generated code (except for line numbers, of course,
where embedded in code/data).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
`QEMU_XEN_PATH` will be configured as `qemu-system-i386` with no clue where, if
`--with-system-qemu` is set without giving a path (as matched in the case `yes`
but not `*`). However, the existence of the executable is checked by `access()`,
that will not look for anywhere in $PATH but the current directory. And since it
is possible for `qemu-system-i386` (or any other configured values) to be
executed from PATH later, we'd better find that in PATH and return the full path
for the caller to check against.
Signed-off-by: Hongbo <hehongbo@mail.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
It makes no sense to request for preprocessor only output and also request
object file generation. Fix the _libxl.api-for-check target to only use
-E (preprocessor output).
Also Clang 20.0 reports an error if both options are used.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Fixes: 2862bf5b6c ('libxl: enforce prohibitions of internal callers')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>
We are missing a way to detect whether a user provided a value for
nr_spis equal to 0 or did not provide any value (default is also 0) which
can cause issues when calculated nr_spis is > 0 and the value from domain
config is 0. Fix it by setting default value for nr_spis to newly added
LIBXL_NR_SPIS_DEFAULT i.e. UINT32_MAX (max supported nr of SPIs is 960
anyway).
Fixes: 55d62b8d46 ("tools/arm: Reject configuration with incorrect nr_spis value")
Reported-by: Luca Fancellu <luca.fancellu@arm.com>
Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Commit cefeffc7e5 marked ACPI tables as NVS in the hvmloader path
because SeaBIOS may otherwise just mark it as RAM. There is, however,
yet another reason to do it even in the PVH path. Xen's incarnation of
AML relies on having access to some ACPI tables (e.g: _STA of Processor
objects relies on reading the processor online bit in its MADT entry)
This is problematic if the OS tries to reclaim ACPI memory for page
tables as it's needed for runtime and can't be reclaimed after the OSPM
is up and running.
Fixes: de6d188a51 ("hvmloader: flip "ACPI data" to "ACPI NVS" type for ACPI table region)"
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
A PCI device may not have a legacy IRQ. In that case, we don't need to
do anything, so don't fail in libxl__arch_hvm_map_gsi() and
libxl__arch_hvm_unmap_gsi().
Requires an updated pciback to return -ENOENT.
Fixes: f97f885c71 ("tools: Add new function to do PIRQ (un)map on PVH dom0")
Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Infinitely retrying the rmdir() invocation makes little sense. While the
original observation was the log filling the disk (due to repeated
"Directory not empty" errors, in turn occurring for unclear reasons),
the loop wants breaking even if there was no error message being logged
(much like is done in the similar loops in libxl__remove_file() and
libxl__remove_file_or_directory()).
Fixes: c4dcbee67e ("libxl: provide libxl__remove_file et al")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>
If the calculated value for nr_spis by the toolstack is bigger than the
value provided by the user, we silently ignore the latter. This is not
consistent with the approach we have in Xen on Arm when we try to reject
incorrect configuration. Also, the documentation for nr_spis is
incorrect as it mentions 991 as the number of max SPIs, where it should
be 960 i.e. (1020 - 32) rounded down to the nearest multiple of 32.
Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
The corresponding code in the Xen qemu repository was not applied from
qemu-xen-4.18.0.
Signed-off-by: James Dingwall <james@dingwall.me.uk>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
... which converts binary content to hex automatically.
Update libxl to match. No API/ABI change.
This removes a latent libxl bug for cases when the buildid is longer than 4092
bytes.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
... which uses XENVER_extraversion2.
In order to do this sensibly, use manual hypercall buffer handling. Not only
does this avoid an extra bounce buffer (we need to strip the xen_varbuf_t
header anyway), it's also shorter and easlier to follow.
Update libxl and the ocaml stubs to match. No API/ABI change in either.
With this change made, `xl info` can now correctly access a >15 char
extraversion:
# xl info xen_version
4.18-unstable+REALLY LONG EXTRAVERSION
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
Add a new "llc_colors" parameter that defines the LLC color assignment for
a domain. The user can specify one or more color ranges using the same
syntax used everywhere else for color config described in the
documentation.
The parameter is defined as a list of strings that represent the color
ranges.
Documentation is also added.
Golang bindings are regenerated.
Based on original work from: Luca Miccio <lucmiccio@gmail.com>
Signed-off-by: Carlo Nonato <carlo.nonato@minervasys.tech>
Signed-off-by: Marco Solieri <marco.solieri@minervasys.tech>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Consider also "Display controller" an IGD, not only "VGA compatible
controller". Specifically, IGD on Raptor Lake has 0x038000 class, not
0x030000.
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>
First instroduce a manifest constant, to avoid open-coding 64 in several
places. Then use this constant to bound the allocation.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Jiqian Chen