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 --- arch/powerpc/tools/.gitignore | 2 + arch/powerpc/tools/Makefile | 10 +++ .../tools/check-fpatchable-function-entry.sh | 25 +++++++ arch/powerpc/tools/checkpatch.sh | 22 ++++++ arch/powerpc/tools/ftrace-gen-ool-stubs.sh | 52 ++++++++++++++ arch/powerpc/tools/ftrace_check.sh | 50 +++++++++++++ arch/powerpc/tools/gcc-check-mprofile-kernel.sh | 26 +++++++ arch/powerpc/tools/head_check.sh | 81 ++++++++++++++++++++++ arch/powerpc/tools/relocs_check.sh | 43 ++++++++++++ arch/powerpc/tools/unrel_branch_check.sh | 79 +++++++++++++++++++++ 10 files changed, 390 insertions(+) create mode 100644 arch/powerpc/tools/.gitignore create mode 100644 arch/powerpc/tools/Makefile create mode 100755 arch/powerpc/tools/check-fpatchable-function-entry.sh create mode 100755 arch/powerpc/tools/checkpatch.sh create mode 100755 arch/powerpc/tools/ftrace-gen-ool-stubs.sh create mode 100755 arch/powerpc/tools/ftrace_check.sh create mode 100755 arch/powerpc/tools/gcc-check-mprofile-kernel.sh create mode 100644 arch/powerpc/tools/head_check.sh create mode 100755 arch/powerpc/tools/relocs_check.sh create mode 100755 arch/powerpc/tools/unrel_branch_check.sh (limited to 'arch/powerpc/tools') diff --git a/arch/powerpc/tools/.gitignore b/arch/powerpc/tools/.gitignore new file mode 100644 index 000000000..ec380a14a --- /dev/null +++ b/arch/powerpc/tools/.gitignore @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +/vmlinux.arch.S diff --git a/arch/powerpc/tools/Makefile b/arch/powerpc/tools/Makefile new file mode 100644 index 000000000..e1f7afcd9 --- /dev/null +++ b/arch/powerpc/tools/Makefile @@ -0,0 +1,10 @@ +# SPDX-License-Identifier: GPL-2.0-or-later + +quiet_cmd_gen_ftrace_ool_stubs = GEN $@ + cmd_gen_ftrace_ool_stubs = $< "$(CONFIG_PPC_FTRACE_OUT_OF_LINE_NUM_RESERVE)" "$(CONFIG_64BIT)" \ + "$(OBJDUMP)" vmlinux.o $@ + +$(obj)/vmlinux.arch.S: $(src)/ftrace-gen-ool-stubs.sh vmlinux.o FORCE + $(call if_changed,gen_ftrace_ool_stubs) + +targets += vmlinux.arch.S diff --git a/arch/powerpc/tools/check-fpatchable-function-entry.sh b/arch/powerpc/tools/check-fpatchable-function-entry.sh new file mode 100755 index 000000000..baed467a0 --- /dev/null +++ b/arch/powerpc/tools/check-fpatchable-function-entry.sh @@ -0,0 +1,25 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +set -e + +# To debug, uncomment the following line +# set -x + +# Output from -fpatchable-function-entry can only vary on ppc64 elfv2, so this +# should not be invoked for other targets. Therefore we can pass in -m64 and +# -mabi explicitly, to take care of toolchains defaulting to other targets. + +# Test whether the compile option -fpatchable-function-entry exists and +# generates appropriate code +echo "int func() { return 0; }" | \ + $* -m64 -mabi=elfv2 -S -x c -O2 -fpatchable-function-entry=2 - -o - 2> /dev/null | \ + grep -q "__patchable_function_entries" + +# Test whether nops are generated after the local entry point +echo "int x; int func() { return x; }" | \ + $* -m64 -mabi=elfv2 -S -x c -O2 -fpatchable-function-entry=2 - -o - 2> /dev/null | \ + awk 'BEGIN { RS = ";" } /\.localentry.*nop.*\n[[:space:]]*nop/ { print $0 }' | \ + grep -q "func:" + +exit 0 diff --git a/arch/powerpc/tools/checkpatch.sh b/arch/powerpc/tools/checkpatch.sh new file mode 100755 index 000000000..91c04802e --- /dev/null +++ b/arch/powerpc/tools/checkpatch.sh @@ -0,0 +1,22 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0+ +# Copyright 2018, Michael Ellerman, IBM Corporation. +# +# Wrapper around checkpatch that uses our preferred settings + +script_base=$(realpath $(dirname $0)) + +exec $script_base/../../../scripts/checkpatch.pl \ + --subjective \ + --no-summary \ + --show-types \ + --ignore ARCH_INCLUDE_LINUX \ + --ignore BIT_MACRO \ + --ignore COMPARISON_TO_NULL \ + --ignore EMAIL_SUBJECT \ + --ignore FILE_PATH_CHANGES \ + --ignore GLOBAL_INITIALISERS \ + --ignore LINE_SPACING \ + --ignore MULTIPLE_ASSIGNMENTS \ + --ignore DT_SPLIT_BINDING_PATCH \ + $@ diff --git a/arch/powerpc/tools/ftrace-gen-ool-stubs.sh b/arch/powerpc/tools/ftrace-gen-ool-stubs.sh new file mode 100755 index 000000000..9218d43ae --- /dev/null +++ b/arch/powerpc/tools/ftrace-gen-ool-stubs.sh @@ -0,0 +1,52 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-or-later + +# Error out on error +set -e + +num_ool_stubs_text_builtin="$1" +is_64bit="$2" +objdump="$3" +vmlinux_o="$4" +arch_vmlinux_S="$5" + +RELOCATION=R_PPC64_ADDR64 +if [ -z "$is_64bit" ]; then + RELOCATION=R_PPC_ADDR32 +fi + +num_ool_stubs_total=$($objdump -r -j __patchable_function_entries -d "$vmlinux_o" | + grep -c "$RELOCATION") +num_ool_stubs_inittext=$($objdump -r -j __patchable_function_entries -d "$vmlinux_o" | + grep -e ".init.text" -e ".text.startup" | grep -c "$RELOCATION") +num_ool_stubs_text=$((num_ool_stubs_total - num_ool_stubs_inittext)) + +if [ "$num_ool_stubs_text" -gt "$num_ool_stubs_text_builtin" ]; then + num_ool_stubs_text_end=$((num_ool_stubs_text - num_ool_stubs_text_builtin)) +else + num_ool_stubs_text_end=0 +fi + +cat > "$arch_vmlinux_S" < +#include +#include + +.pushsection .tramp.ftrace.text,"aw" +SYM_DATA(ftrace_ool_stub_text_end_count, .long $num_ool_stubs_text_end) + +SYM_START(ftrace_ool_stub_text_end, SYM_L_GLOBAL, .balign SZL) +#if $num_ool_stubs_text_end + .space $num_ool_stubs_text_end * FTRACE_OOL_STUB_SIZE +#endif +SYM_CODE_END(ftrace_ool_stub_text_end) +.popsection + +.pushsection .tramp.ftrace.init,"aw" +SYM_DATA(ftrace_ool_stub_inittext_count, .long $num_ool_stubs_inittext) + +SYM_START(ftrace_ool_stub_inittext, SYM_L_GLOBAL, .balign SZL) + .space $num_ool_stubs_inittext * FTRACE_OOL_STUB_SIZE +SYM_CODE_END(ftrace_ool_stub_inittext) +.popsection +EOF diff --git a/arch/powerpc/tools/ftrace_check.sh b/arch/powerpc/tools/ftrace_check.sh new file mode 100755 index 000000000..405e7e306 --- /dev/null +++ b/arch/powerpc/tools/ftrace_check.sh @@ -0,0 +1,50 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0-or-later +# +# This script checks vmlinux to ensure that all functions can call ftrace_caller() either directly, +# or through the stub, ftrace_tramp_text, at the end of kernel text. + +# Error out if any command fails +set -e + +# Allow for verbose output +if [ "$V" = "1" ]; then + set -x +fi + +if [ $# -lt 2 ]; then + echo "$0 [path to nm] [path to vmlinux]" 1>&2 + exit 1 +fi + +# Have Kbuild supply the path to nm so we handle cross compilation. +nm="$1" +vmlinux="$2" + +stext_addr=$($nm "$vmlinux" | grep -e " [TA] _stext$" | \ + cut -d' ' -f1 | tr '[:lower:]' '[:upper:]') +ftrace_caller_addr=$($nm "$vmlinux" | grep -e " T ftrace_caller$" | \ + cut -d' ' -f1 | tr '[:lower:]' '[:upper:]') +ftrace_tramp_addr=$($nm "$vmlinux" | grep -e " T ftrace_tramp_text$" | \ + cut -d' ' -f1 | tr '[:lower:]' '[:upper:]') + +ftrace_caller_offset=$(echo "ibase=16;$ftrace_caller_addr - $stext_addr" | bc) +ftrace_tramp_offset=$(echo "ibase=16;$ftrace_tramp_addr - $ftrace_caller_addr" | bc) +sz_32m=$(printf "%d" 0x2000000) +sz_64m=$(printf "%d" 0x4000000) + +# ftrace_caller - _stext < 32M +if [ "$ftrace_caller_offset" -ge "$sz_32m" ]; then + echo "ERROR: ftrace_caller (0x$ftrace_caller_addr) is beyond 32MiB of _stext" 1>&2 + echo "ERROR: consider disabling CONFIG_FUNCTION_TRACER, or reducing the size \ + of kernel text" 1>&2 + exit 1 +fi + +# ftrace_tramp_text - ftrace_caller < 64M +if [ "$ftrace_tramp_offset" -ge "$sz_64m" ]; then + echo "ERROR: kernel text extends beyond 64MiB from ftrace_caller" 1>&2 + echo "ERROR: consider disabling CONFIG_FUNCTION_TRACER, or reducing the size \ + of kernel text" 1>&2 + exit 1 +fi diff --git a/arch/powerpc/tools/gcc-check-mprofile-kernel.sh b/arch/powerpc/tools/gcc-check-mprofile-kernel.sh new file mode 100755 index 000000000..6193b0ed0 --- /dev/null +++ b/arch/powerpc/tools/gcc-check-mprofile-kernel.sh @@ -0,0 +1,26 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +set -e + +# To debug, uncomment the following line +# set -x + +# -mprofile-kernel is only supported on 64-bit with ELFv2, so this should not +# be invoked for other targets. Therefore we can pass in -m64 and -mabi +# explicitly, to take care of toolchains defaulting to other targets. + +# Test whether the compile option -mprofile-kernel exists and generates +# profiling code (ie. a call to _mcount()). +echo "int func() { return 0; }" | \ + $* -m64 -mabi=elfv2 -S -x c -O2 -p -mprofile-kernel - -o - \ + 2> /dev/null | grep -q "_mcount" + +# Test whether the notrace attribute correctly suppresses calls to _mcount(). + +echo -e "#include \nnotrace int func() { return 0; }" | \ + $* -m64 -mabi=elfv2 -S -x c -O2 -p -mprofile-kernel - -o - \ + 2> /dev/null | grep -q "_mcount" && \ + exit 1 + +exit 0 diff --git a/arch/powerpc/tools/head_check.sh b/arch/powerpc/tools/head_check.sh new file mode 100644 index 000000000..a9cd06958 --- /dev/null +++ b/arch/powerpc/tools/head_check.sh @@ -0,0 +1,81 @@ +#!/bin/sh +# Copyright © 2016 IBM Corporation + +# This program is free software; you can redistribute it and/or +# modify it under the terms of the GNU General Public License +# as published by the Free Software Foundation; either version +# 2 of the License, or (at your option) any later version. + +# This script checks the head of a vmlinux for linker stubs that +# break our placement of fixed-location code for 64-bit. + +# based on relocs_check.pl +# Copyright © 2009 IBM Corporation + +# NOTE! +# +# If the build dies here, it's likely code in head_64.S/exception-64*.S or +# nearby, is branching to labels it can't reach directly, which results in the +# linker inserting branch stubs. This can move code around in ways that break +# the fixed section calculations (head-64.h). To debug this, disassemble the +# vmlinux and look for branch stubs (long_branch, plt_branch, etc.) in the +# fixed section region (0 - 0x8000ish). Check what code is calling those stubs, +# and perhaps change so a direct branch can reach. +# +# A ".linker_stub_catch" section is used to catch some stubs generated by +# early .text code, which tend to get placed at the start of the section. +# If there are too many such stubs, they can overflow this section. Expanding +# it may help (or reducing the number of stub branches). +# +# Linker stubs use the TOC pointer, so even if fixed section code could +# tolerate them being inserted into head code, they can't be allowed in low +# level entry code (boot, interrupt vectors, etc) until r2 is set up. This +# could cause the kernel to die in early boot. + +# Allow for verbose output +if [ "$V" = "1" ]; then + set -x +fi + +if [ $# -lt 2 ]; then + echo "$0 [path to nm] [path to vmlinux]" 1>&2 + exit 1 +fi + +# Have Kbuild supply the path to nm so we handle cross compilation. +nm="$1" +vmlinux="$2" + +# gcc-4.6-era toolchain make _stext an A (absolute) symbol rather than T +$nm "$vmlinux" | grep -e " [TA] _stext$" -e " t start_first_256B$" -e " a text_start$" -e " t start_text$" > .tmp_symbols.txt + + +vma=$(grep -e " [TA] _stext$" .tmp_symbols.txt | cut -d' ' -f1) + +expected_start_head_addr="$vma" + +start_head_addr=$(grep " t start_first_256B$" .tmp_symbols.txt | cut -d' ' -f1) + +if [ "$start_head_addr" != "$expected_start_head_addr" ]; then + echo "ERROR: head code starts at $start_head_addr, should be $expected_start_head_addr" 1>&2 + echo "ERROR: try to enable LD_HEAD_STUB_CATCH config option" 1>&2 + echo "ERROR: see comments in arch/powerpc/tools/head_check.sh" 1>&2 + + exit 1 +fi + +top_vma=$(echo "$vma" | cut -d'0' -f1) + +expected_start_text_addr=$(grep " a text_start$" .tmp_symbols.txt | cut -d' ' -f1 | sed "s/^0/$top_vma/") + +start_text_addr=$(grep " t start_text$" .tmp_symbols.txt | cut -d' ' -f1) + +if [ "$start_text_addr" != "$expected_start_text_addr" ]; then + echo "ERROR: start_text address is $start_text_addr, should be $expected_start_text_addr" 1>&2 + echo "ERROR: try to enable LD_HEAD_STUB_CATCH config option" 1>&2 + echo "ERROR: see comments in arch/powerpc/tools/head_check.sh" 1>&2 + + exit 1 +fi + +rm -f .tmp_symbols.txt diff --git a/arch/powerpc/tools/relocs_check.sh b/arch/powerpc/tools/relocs_check.sh new file mode 100755 index 000000000..6b350e750 --- /dev/null +++ b/arch/powerpc/tools/relocs_check.sh @@ -0,0 +1,43 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-or-later + +# Copyright © 2015 IBM Corporation + + +# This script checks the relocations of a vmlinux for "suspicious" +# relocations. + +# based on relocs_check.pl +# Copyright © 2009 IBM Corporation + +if [ $# -lt 3 ]; then + echo "$0 [path to objdump] [path to nm] [path to vmlinux]" 1>&2 + exit 1 +fi + +bad_relocs=$( +${srctree}/scripts/relocs_check.sh "$@" | + # These relocations are okay + # On PPC64: + # R_PPC64_RELATIVE, R_PPC64_NONE + # On PPC: + # R_PPC_RELATIVE, R_PPC_ADDR16_HI, + # R_PPC_ADDR16_HA,R_PPC_ADDR16_LO, + # R_PPC_NONE + grep -F -w -v 'R_PPC64_RELATIVE +R_PPC64_NONE +R_PPC64_UADDR64 +R_PPC_ADDR16_LO +R_PPC_ADDR16_HI +R_PPC_ADDR16_HA +R_PPC_RELATIVE +R_PPC_NONE' +) + +if [ -z "$bad_relocs" ]; then + exit 0 +fi + +num_bad=$(echo "$bad_relocs" | wc -l) +echo "WARNING: $num_bad bad relocations" +echo "$bad_relocs" diff --git a/arch/powerpc/tools/unrel_branch_check.sh b/arch/powerpc/tools/unrel_branch_check.sh new file mode 100755 index 000000000..8301efee1 --- /dev/null +++ b/arch/powerpc/tools/unrel_branch_check.sh @@ -0,0 +1,79 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0+ +# Copyright © 2016,2020 IBM Corporation +# +# This script checks the unrelocated code of a vmlinux for "suspicious" +# branches to relocated code (head_64.S code). + +# Have Kbuild supply the path to objdump and nm so we handle cross compilation. +objdump="$1" +nm="$2" +vmlinux="$3" + +kstart=0xc000000000000000 + +end_intr=0x$($nm -p "$vmlinux" | + sed -E -n '/\s+[[:alpha:]]\s+__end_interrupts\s*$/{s///p;q}') +if [ "$end_intr" = "0x" ]; then + exit 0 +fi + +# we know that there is a correct branch to +# __start_initialization_multiplatform, so find its address +# so we can exclude it. +sim=0x$($nm -p "$vmlinux" | + sed -E -n '/\s+[[:alpha:]]\s+__start_initialization_multiplatform\s*$/{s///p;q}') + +$objdump -D --no-show-raw-insn --start-address="$kstart" --stop-address="$end_intr" "$vmlinux" | +sed -E -n ' +# match lines that start with a kernel address +/^c[0-9a-f]*:\s*b/ { + # drop branches via ctr or lr + /\= 0x2000000 )); then + to=$(( to - 0x4000000 )) + fi + elif (( to >= 0x8000 )); then + to=$(( to - 0x10000 )) + fi + printf -v to '0x%x' $(( "0x$from" + to )) + ;; + *) printf 'Unkown branch format\n' + ;; + esac + if [ "$to" = "$sim" ]; then + continue + fi + if (( to > end_intr )); then + if $all_good; then + printf '%s\n' 'WARNING: Unrelocated relative branches' + all_good=false + fi + printf '%s %s-> %s %s\n' "$from" "$branch" "$to" "$sym" + fi +done + +$all_good + +} -- cgit v1.3.1