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 --- scripts/dtc/dtx_diff | 361 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 361 insertions(+) create mode 100755 scripts/dtc/dtx_diff (limited to 'scripts/dtc/dtx_diff') diff --git a/scripts/dtc/dtx_diff b/scripts/dtc/dtx_diff new file mode 100755 index 000000000..f2bbde4bb --- /dev/null +++ b/scripts/dtc/dtx_diff @@ -0,0 +1,361 @@ +#! /bin/bash +# SPDX-License-Identifier: GPL-2.0-only + +# Copyright (C) 2015 Frank Rowand +# + + +usage() { + + # use spaces instead of tabs in the usage message + cat >&2 <tmp_dtx_1.dts + `basename $0` ARCH=arch_of_dtx_2 DTx_2 >tmp_dtx_2.dts + `basename $0` tmp_dtx_1.dts tmp_dtx_2.dts + rm tmp_dtx_1.dts tmp_dtx_2.dts + + If DTx_1 and DTx_2 are in different directories, then this script will + add the path of DTx_1 and DTx_2 to the include paths. If DTx_2 includes + a local file that exists in both the path of DTx_1 and DTx_2 then the + file in the path of DTx_1 will incorrectly be included. Possible + workaround: + + `basename $0` DTx_1 >tmp_dtx_1.dts + `basename $0` DTx_2 >tmp_dtx_2.dts + `basename $0` tmp_dtx_1.dts tmp_dtx_2.dts + rm tmp_dtx_1.dts tmp_dtx_2.dts + +eod +} + + +compile_to_dts() { + + dtx="$1" + dtc_include="$2" + + if [ -d "${dtx}" ] ; then + + # ----- input is file tree + + if ( ! ${DTC} -I fs ${dtx} ) ; then + exit 3 + fi + + elif [ -f "${dtx}" ] && [ -r "${dtx}" ] ; then + + magic=`hexdump -n 4 -e '/1 "%02x"' ${dtx}` + if [ "${magic}" = "d00dfeed" ] ; then + + # ----- input is FDT (binary blob) + + if ( ! ${DTC} -I dtb ${dtx} ) ; then + exit 3 + fi + + return + + fi + + # ----- input is DTS (source) + + if ( cpp ${cpp_flags} -x assembler-with-cpp ${dtx} \ + | ${DTC} ${dtc_include} -I dts ) ; then + return + fi + + echo "" >&2 + echo "Possible hints to resolve the above error:" >&2 + echo " (hints might not fix the problem)" >&2 + + hint_given=0 + + if [ "${ARCH}" = "" ] ; then + hint_given=1 + echo "" >&2 + echo " shell variable \$ARCH not set" >&2 + fi + + dtx_arch=`echo "/${dtx}" | sed -e 's|.*/arch/||' -e 's|/.*||'` + + if [ "${dtx_arch}" != "" -a "${dtx_arch}" != "${ARCH}" ] ; then + hint_given=1 + echo "" >&2 + echo " architecture ${dtx_arch} is in file path," >&2 + echo " but does not match shell variable \$ARCH" >&2 + echo " >>\$ARCH<< is: >>${ARCH}<<" >&2 + fi + + if [ ! -d ${srctree}/arch/${ARCH} ] ; then + hint_given=1 + echo "" >&2 + echo " ${srctree}/arch/${ARCH}/ does not exist" >&2 + echo " Is \$ARCH='${ARCH}' correct?" >&2 + echo " Possible fix: use '-s' option" >&2 + + git_root=`git rev-parse --show-toplevel 2>/dev/null` + if [ -d ${git_root}/arch/ ] ; then + echo " Possible fix: use '-S' option" >&2 + fi + fi + + if [ $hint_given = 0 ] ; then + echo "" >&2 + echo " No hints available." >&2 + fi + + echo "" >&2 + + exit 3 + + else + echo "" >&2 + echo "ERROR: ${dtx} does not exist or is not readable" >&2 + echo "" >&2 + exit 2 + fi + +} + + +# ----- start of script + +annotate="" +cmd_diff=0 +diff_flags="-u" +diff_color="" +dtx_file_1="" +dtx_file_2="" +dtc_sort="-s" +help=0 +srctree="" + + +while [ $# -gt 0 ] ; do + + case $1 in + + -c | --color ) + if diff --color /dev/null /dev/null 2>/dev/null ; then + diff_color="--color=always" + fi + shift + ;; + + -f ) + diff_flags="--unified=999999" + shift + ;; + + -h | -help | --help ) + help=1 + shift + ;; + + -s ) + srctree="$2" + shift 2 + ;; + + -S ) + git_root=`git rev-parse --show-toplevel 2>/dev/null` + srctree="${git_root}" + shift + ;; + + -T | --annotate ) + if [ "${annotate}" = "" ] ; then + annotate="-T" + elif [ "${annotate}" = "-T" ] ; then + annotate="-T -T" + fi + shift + ;; + -u ) + dtc_sort="" + shift + ;; + + *) + if [ "${dtx_file_1}" = "" ] ; then + dtx_file_1="$1" + elif [ "${dtx_file_2}" = "" ] ; then + dtx_file_2="$1" + else + echo "" >&2 + echo "ERROR: Unexpected parameter: $1" >&2 + echo "" >&2 + exit 2 + fi + shift + ;; + + esac + +done + +if [ "${srctree}" = "" ] ; then + srctree="." +fi + +if [ "${dtx_file_2}" != "" ]; then + cmd_diff=1 +fi + +if (( ${help} )) ; then + usage + exit 1 +fi + +# this must follow check for ${help} +if [ "${dtx_file_1}" = "" ]; then + echo "" >&2 + echo "ERROR: parameter DTx required" >&2 + echo "" >&2 + exit 2 +fi + + +# ----- prefer dtc from linux kernel, allow fallback to dtc in $PATH + +if [ "${KBUILD_OUTPUT:0:2}" = ".." ] ; then + __KBUILD_OUTPUT="${srctree}/${KBUILD_OUTPUT}" +elif [ "${KBUILD_OUTPUT}" = "" ] ; then + __KBUILD_OUTPUT="." +else + __KBUILD_OUTPUT="${KBUILD_OUTPUT}" +fi + +DTC="${__KBUILD_OUTPUT}/scripts/dtc/dtc" + +if [ ! -x ${DTC} ] ; then + __DTC="dtc" + if grep -q "^CONFIG_DTC=y" ${__KBUILD_OUTPUT}/.config 2>/dev/null; then + make_command=' + make scripts' + else + make_command=' + Enable CONFIG_DTC in the kernel configuration + make scripts' + fi + if ( ! which ${__DTC} >/dev/null ) ; then + + # use spaces instead of tabs in the error message + cat >&2 <