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/firmware-guide/acpi/aml-debugger.rst | 75 ++++++++++++++++++++++ 1 file changed, 75 insertions(+) create mode 100644 Documentation/firmware-guide/acpi/aml-debugger.rst (limited to 'Documentation/firmware-guide/acpi/aml-debugger.rst') diff --git a/Documentation/firmware-guide/acpi/aml-debugger.rst b/Documentation/firmware-guide/acpi/aml-debugger.rst new file mode 100644 index 000000000..a889d43bc --- /dev/null +++ b/Documentation/firmware-guide/acpi/aml-debugger.rst @@ -0,0 +1,75 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: + +================ +The AML Debugger +================ + +:Copyright: |copy| 2016, Intel Corporation +:Author: Lv Zheng + + +This document describes the usage of the AML debugger embedded in the Linux +kernel. + +1. Build the debugger +===================== + +The following kernel configuration items are required to enable the AML +debugger interface from the Linux kernel:: + + CONFIG_ACPI_DEBUGGER=y + CONFIG_ACPI_DEBUGGER_USER=m + +The userspace utilities can be built from the kernel source tree using +the following commands:: + + $ cd tools + $ make acpi + +The resultant userspace tool binary is then located at:: + + tools/power/acpi/acpidbg + +It can be installed to system directories by running "make install" (as a +sufficiently privileged user). + +2. Start the userspace debugger interface +========================================= + +After booting the kernel with the debugger built-in, the debugger can be +started by using the following commands:: + + # mount -t debugfs none /sys/kernel/debug + # modprobe acpi_dbg + # tools/power/acpi/acpidbg + +That spawns the interactive AML debugger environment where you can execute +debugger commands. + +The commands are documented in the "ACPICA Overview and Programmer Reference" +that can be downloaded from + +https://acpica.org/documentation + +The detailed debugger commands reference is located in Chapter 12 "ACPICA +Debugger Reference". The "help" command can be used for a quick reference. + +3. Stop the userspace debugger interface +======================================== + +The interactive debugger interface can be closed by pressing Ctrl+C or using +the "quit" or "exit" commands. When finished, unload the module with:: + + # rmmod acpi_dbg + +The module unloading may fail if there is an acpidbg instance running. + +4. Run the debugger in a script +=============================== + +It may be useful to run the AML debugger in a test script. "acpidbg" supports +this in a special "batch" mode. For example, the following command outputs +the entire ACPI namespace:: + + # acpidbg -b "namespace" -- cgit v1.3.1