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9694d1ca6a
On systems with humongous pages (16GiB) and 32bit int it's easy to hit integer overflow in virNumaGetPages(). What happens is, inside of virNumaGetPages() as we process hugepages for given NUMA node (e.g. in order to produce capabilities XML), we keep a sum of sizes of pools in an ULL variable (huge_page_sum). In each iteration, the variable is incremented by 1024 * page_size * page_avail. Now, page_size is just an uint, so we have: ULL += U * U * ULL; and because of associativity, U * U is computed first and since we have two operands of the same type, no type expansion happens. But this means, for humongous pages (like 16GiB) the multiplication overflows. Therefore, move the multiplication out of the loop. This helps in two ways: 1) now we have ULL += U * ULL; which expands the uint in multiplication, 2) it saves couple of CPU cycles. Resolves: https://issues.redhat.com/browse/RHEL-16749 Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Ján Tomko <jtomko@redhat.com> |
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==============================
Libvirt API for virtualization
==============================
Libvirt provides a portable, long term stable C API for managing the
virtualization technologies provided by many operating systems. It
includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware
vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER
Hypervisor.
For some of these hypervisors, it provides a stateful management
daemon which runs on the virtualization host allowing access to the
API both by non-privileged local users and remote users.
Layered packages provide bindings of the libvirt C API into other
languages including Python, Perl, PHP, Go, Java, OCaml, as well as
mappings into object systems such as GObject, CIM and SNMP.
Further information about the libvirt project can be found on the
website:
https://libvirt.org
License
=======
The libvirt C API is distributed under the terms of GNU Lesser General
Public License, version 2.1 (or later). Some parts of the code that are
not part of the C library may have the more restrictive GNU General
Public License, version 2.0 (or later). See the files ``COPYING.LESSER``
and ``COPYING`` for full license terms & conditions.
Installation
============
Instructions on building and installing libvirt can be found on the website:
https://libvirt.org/compiling.html
Contributing
============
The libvirt project welcomes contributions in many ways. For most components
the best way to contribute is to send patches to the primary development
mailing list. Further guidance on this can be found on the website:
https://libvirt.org/contribute.html
Contact
=======
The libvirt project has two primary mailing lists:
* users@lists.libvirt.org (**for user discussions**)
* devel@lists.libvirt.org (**for development only**)
Further details on contacting the project are available on the website:
https://libvirt.org/contact.html