From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier. Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Cc: stable@vger.kernel.org Reported-by: Stefan Teodorescu Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- Documentation/admin-guide/LSM/index.rst | 51 +++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 Documentation/admin-guide/LSM/index.rst (limited to 'Documentation/admin-guide/LSM/index.rst') diff --git a/Documentation/admin-guide/LSM/index.rst b/Documentation/admin-guide/LSM/index.rst new file mode 100644 index 000000000..b44ef68f6 --- /dev/null +++ b/Documentation/admin-guide/LSM/index.rst @@ -0,0 +1,51 @@ +=========================== +Linux Security Module Usage +=========================== + +The Linux Security Module (LSM) framework provides a mechanism for +various security checks to be hooked by new kernel extensions. The name +"module" is a bit of a misnomer since these extensions are not actually +loadable kernel modules. Instead, they are selectable at build-time via +CONFIG_DEFAULT_SECURITY and can be overridden at boot-time via the +``"security=..."`` kernel command line argument, in the case where multiple +LSMs were built into a given kernel. + +The primary users of the LSM interface are Mandatory Access Control +(MAC) extensions which provide a comprehensive security policy. Examples +include SELinux, Smack, Tomoyo, and AppArmor. In addition to the larger +MAC extensions, other extensions can be built using the LSM to provide +specific changes to system operation when these tweaks are not available +in the core functionality of Linux itself. + +The Linux capabilities modules will always be included. This may be +followed by any number of "minor" modules and at most one "major" module. +For more details on capabilities, see ``capabilities(7)`` in the Linux +man-pages project. + +A list of the active security modules can be found by reading +``/sys/kernel/security/lsm``. This is a comma separated list, and +will always include the capability module. The list reflects the +order in which checks are made. The capability module will always +be first, followed by any "minor" modules (e.g. Yama) and then +the one "major" module (e.g. SELinux) if there is one configured. + +Process attributes associated with "major" security modules should +be accessed and maintained using the special files in ``/proc/.../attr``. +A security module may maintain a module specific subdirectory there, +named after the module. ``/proc/.../attr/smack`` is provided by the Smack +security module and contains all its special files. The files directly +in ``/proc/.../attr`` remain as legacy interfaces for modules that provide +subdirectories. + +.. toctree:: + :maxdepth: 1 + + apparmor + LoadPin + SELinux + Smack + tomoyo + Yama + SafeSetID + ipe + landlock -- cgit v1.3.1