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 --- tools/scripts/Makefile.include | 243 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 243 insertions(+) create mode 100644 tools/scripts/Makefile.include (limited to 'tools/scripts/Makefile.include') diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include new file mode 100644 index 000000000..378387f62 --- /dev/null +++ b/tools/scripts/Makefile.include @@ -0,0 +1,243 @@ +# SPDX-License-Identifier: GPL-2.0 +ifneq ($(O),) +ifeq ($(origin O), command line) + $(if $(shell cd $(PWD); test -d $(O) || echo $(O)),$(error O=$(O) does not exist),) + ABSOLUTE_O := $(shell cd $(PWD); cd $(O) ; pwd) + OUTPUT := $(ABSOLUTE_O)/$(if $(subdir),$(subdir)/) + COMMAND_O := O=$(ABSOLUTE_O) +ifeq ($(objtree),) + objtree := $(O) +endif +endif +endif + +# check that the output directory actually exists +ifneq ($(OUTPUT),) +OUTDIR := $(shell cd $(OUTPUT) && pwd) +$(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist)) +endif + +# +# Include saner warnings here, which can catch bugs: +# +EXTRA_WARNINGS := -Wbad-function-cast +EXTRA_WARNINGS += -Wdeclaration-after-statement +EXTRA_WARNINGS += -Wformat-security +EXTRA_WARNINGS += -Wformat-y2k +EXTRA_WARNINGS += -Winit-self +EXTRA_WARNINGS += -Wmissing-declarations +EXTRA_WARNINGS += -Wmissing-prototypes +EXTRA_WARNINGS += -Wnested-externs +EXTRA_WARNINGS += -Wno-system-headers +EXTRA_WARNINGS += -Wold-style-definition +EXTRA_WARNINGS += -Wpacked +EXTRA_WARNINGS += -Wredundant-decls +EXTRA_WARNINGS += -Wstrict-prototypes +EXTRA_WARNINGS += -Wswitch-default +EXTRA_WARNINGS += -Wswitch-enum +EXTRA_WARNINGS += -Wundef +EXTRA_WARNINGS += -Wwrite-strings +EXTRA_WARNINGS += -Wformat +EXTRA_WARNINGS += -Wno-type-limits + +# Makefiles suck: This macro sets a default value of $(2) for the +# variable named by $(1), unless the variable has been set by +# environment or command line. This is necessary for CC and AR +# because make sets default values, so the simpler ?= approach +# won't work as expected. +define allow-override + $(if $(or $(findstring environment,$(origin $(1))),\ + $(findstring command line,$(origin $(1)))),,\ + $(eval $(1) = $(2))) +endef + +ifneq ($(LLVM),) + ifneq ($(filter %/,$(LLVM)),) + LLVM_PREFIX := $(LLVM) + else ifneq ($(filter -%,$(LLVM)),) + LLVM_SUFFIX := $(LLVM) + else ifneq ($(LLVM),1) + $(error Invalid value for LLVM, see Documentation/kbuild/llvm.rst) + endif + + $(call allow-override,CC,$(LLVM_PREFIX)clang$(LLVM_SUFFIX)) + $(call allow-override,CLANG,$(LLVM_PREFIX)clang$(LLVM_SUFFIX)) + $(call allow-override,HOSTCC,$(LLVM_PREFIX)clang$(LLVM_SUFFIX)) + $(call allow-override,AR,$(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX)) + $(call allow-override,HOSTAR,$(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX)) + $(call allow-override,LD,$(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX)) + $(call allow-override,HOSTLD,$(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX)) + $(call allow-override,CXX,$(LLVM_PREFIX)clang++$(LLVM_SUFFIX)) + $(call allow-override,STRIP,$(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX)) + $(call allow-override,LLVM_STRIP,$(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX)) + $(call allow-override,LLC,$(LLVM_PREFIX)llc$(LLVM_SUFFIX)) + $(call allow-override,LLVM_CONFIG,$(LLVM_PREFIX)llvm-config$(LLVM_SUFFIX)) + $(call allow-override,LLVM_OBJCOPY,$(LLVM_PREFIX)llvm-objcopy$(LLVM_SUFFIX)) + $(call allow-override,READELF,$(LLVM_PREFIX)llvm-readelf$(LLVM_SUFFIX)) + $(call allow-override,HOSTREADELF,$(LLVM_PREFIX)llvm-readelf$(LLVM_SUFFIX)) +else + # Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix. + $(call allow-override,CC,$(CROSS_COMPILE)gcc) + $(call allow-override,AR,$(CROSS_COMPILE)ar) + $(call allow-override,LD,$(CROSS_COMPILE)ld) + $(call allow-override,CXX,$(CROSS_COMPILE)g++) + $(call allow-override,STRIP,$(CROSS_COMPILE)strip) + $(call allow-override,READELF,$(CROSS_COMPILE)readelf) + + # Host versions aren't prefixed + $(call allow-override,HOSTAR,ar) + $(call allow-override,HOSTCC,gcc) + $(call allow-override,HOSTLD,ld) + $(call allow-override,HOSTREADELF,readelf) + + # Some tools still require Clang, LLC and/or LLVM utils + $(call allow-override,CLANG,clang) + $(call allow-override,LLC,llc) + $(call allow-override,LLVM_CONFIG,llvm-config) + $(call allow-override,LLVM_OBJCOPY,llvm-objcopy) + $(call allow-override,LLVM_STRIP,llvm-strip) +endif + +# The CC_NO_CLANG probe also runs at parse time for targets that never +# compile, so guard it with 'command -v': when the compiler is not yet +# installed, e.g. the first install-build-deps run, it would otherwise +# spew "gcc: not found". Only the first word of CC is consulted, as CC +# may carry arguments, e.g. 'ccache gcc'. A missing compiler leaves +# CC_NO_CLANG at 1, as if the probe had failed. +CC_NO_CLANG := $(shell if command -v $(firstword $(CC)) >/dev/null 2>&1; then $(CC) -dM -E -x c /dev/null; fi | grep -Fq "__clang__"; echo $$?) + +# Some tools require bpftool +SYSTEM_BPFTOOL ?= bpftool + +RUSTC ?= rustc + +ifeq ($(CC_NO_CLANG), 1) +EXTRA_WARNINGS += -Wstrict-aliasing=3 + +else ifneq ($(CROSS_COMPILE),) +# Allow userspace to override CLANG_CROSS_FLAGS to specify their own +# sysroots and flags or to avoid the GCC call in pure Clang builds. +ifeq ($(CLANG_CROSS_FLAGS),) +CLANG_TARGET := $(notdir $(CROSS_COMPILE:%-=%)) +CLANG_TARGET := $(subst s390-linux,s390x-linux,$(CLANG_TARGET)) +CLANG_CROSS_FLAGS := --target=$(CLANG_TARGET) +GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)gcc 2>/dev/null)) +ifneq ($(GCC_TOOLCHAIN_DIR),) +CLANG_CROSS_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE)) +CLANG_CROSS_FLAGS += --sysroot=$(shell $(CROSS_COMPILE)gcc -print-sysroot) +CLANG_CROSS_FLAGS += --gcc-toolchain=$(realpath $(GCC_TOOLCHAIN_DIR)/..) +endif # GCC_TOOLCHAIN_DIR +endif # CLANG_CROSS_FLAGS +CFLAGS += $(CLANG_CROSS_FLAGS) +AFLAGS += $(CLANG_CROSS_FLAGS) +else +CLANG_CROSS_FLAGS := +endif # CROSS_COMPILE + +# Hack to avoid type-punned warnings on old systems such as RHEL5: +# We should be changing CFLAGS and checking gcc version, but this +# will do for now and keep the above -Wstrict-aliasing=3 in place +# in newer systems. +# Needed for the __raw_cmpxchg in tools/arch/x86/include/asm/cmpxchg.h +# +# See https://lore.kernel.org/lkml/9a8748490611281710g78402fbeh8ff7fcc162dbcbca@mail.gmail.com/ +# and https://gcc.gnu.org/gcc-4.8/changes.html, +# that takes into account Linus's comments (search for Wshadow) for the reasoning about +# -Wshadow not being interesting before gcc 4.8. + +ifneq ($(filter 3.%,$(MAKE_VERSION)),) # make-3 +EXTRA_WARNINGS += -fno-strict-aliasing +EXTRA_WARNINGS += -Wno-shadow +else +EXTRA_WARNINGS += -Wshadow +endif + +ifneq ($(findstring $(MAKEFLAGS), w),w) +PRINT_DIR = --no-print-directory +else +NO_SUBDIR = : +endif + +# Beautify output +# --------------------------------------------------------------------------- +# +# Most of build commands in Kbuild start with "cmd_". You can optionally define +# "quiet_cmd_*". If defined, the short log is printed. Otherwise, no log from +# that command is printed by default. +# +# e.g.) +# quiet_cmd_depmod = DEPMOD $(MODLIB) +# cmd_depmod = $(srctree)/scripts/depmod.sh $(DEPMOD) $(KERNELRELEASE) +# +# A simple variant is to prefix commands with $(Q) - that's useful +# for commands that shall be hidden in non-verbose mode. +# +# $(Q)$(MAKE) $(build)=scripts/basic +# +# To put more focus on warnings, be less verbose as default +# Use 'make V=1' to see the full commands + +ifeq ($(V),1) + quiet = + Q = +else + quiet = quiet_ + Q = @ +endif + +# If the user is running make -s (silent mode), suppress echoing of commands +# make-4.0 (and later) keep single letter options in the 1st word of MAKEFLAGS. +ifeq ($(filter 3.%,$(MAKE_VERSION)),) +short-opts := $(firstword -$(MAKEFLAGS)) +else +short-opts := $(filter-out --%,$(MAKEFLAGS)) +endif + +ifneq ($(findstring s,$(short-opts)),) + silent=1 + quiet=silent_ +endif + +export quiet Q + +# +# Define a callable command for descending to a new directory +# +# Call by doing: $(call descend,directory[,target]) +# +descend = \ + +mkdir -p $(OUTPUT)$(1) && \ + $(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2) + +QUIET_SUBDIR0 = +$(MAKE) $(COMMAND_O) -C # space to separate -C and subdir +QUIET_SUBDIR1 = + +ifneq ($(silent),1) + ifneq ($(V),1) + QUIET_CC = @echo ' CC '$@; + QUIET_CC_FPIC = @echo ' CC FPIC '$@; + QUIET_CLANG = @echo ' CLANG '$@; + QUIET_AR = @echo ' AR '$@; + QUIET_LINK = @echo ' LINK '$@; + QUIET_MKDIR = @echo ' MKDIR '$@; + QUIET_GEN = @echo ' GEN '$@; + QUIET_SUBDIR0 = +@subdir= + QUIET_SUBDIR1 = ;$(NO_SUBDIR) \ + echo ' SUBDIR '$$subdir; \ + $(MAKE) $(PRINT_DIR) -C $$subdir + QUIET_FLEX = @echo ' FLEX '$@; + QUIET_BISON = @echo ' BISON '$@; + QUIET_GENSKEL = @echo ' GENSKEL '$@; + + descend = \ + +@echo ' DESCEND '$(1); \ + mkdir -p $(OUTPUT)$(1) && \ + $(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2) + + QUIET_CLEAN = @printf ' CLEAN %s\n' $1; + QUIET_INSTALL = @printf ' INSTALL %s\n' $1; + QUIET_UNINST = @printf ' UNINST %s\n' $1; + endif +endif + +pound := \# -- cgit v1.3.1