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/Makefile.host | 165 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 165 insertions(+) create mode 100644 scripts/Makefile.host (limited to 'scripts/Makefile.host') diff --git a/scripts/Makefile.host b/scripts/Makefile.host new file mode 100644 index 000000000..c1dedf646 --- /dev/null +++ b/scripts/Makefile.host @@ -0,0 +1,165 @@ +# SPDX-License-Identifier: GPL-2.0 + +# LEX +# --------------------------------------------------------------------------- +quiet_cmd_flex = LEX $@ + cmd_flex = $(LEX) -o$@ -L $< + +$(obj)/%.lex.c: $(src)/%.l FORCE + $(call if_changed,flex) + +# YACC +# --------------------------------------------------------------------------- +quiet_cmd_bison = YACC $(basename $@).[ch] + cmd_bison = $(YACC) -o $(basename $@).c --defines=$(basename $@).h -t -l $< + +$(obj)/%.tab.c $(obj)/%.tab.h: $(src)/%.y FORCE + $(call if_changed,bison) + +# ========================================================================== +# Building binaries on the host system +# Binaries are used during the compilation of the kernel, for example +# to preprocess a data file. +# +# Both C and C++ are supported, but preferred language is C for such utilities. +# Rust is also supported, but it may only be used in scenarios where a Rust +# toolchain is required to be available (e.g. when `CONFIG_RUST` is enabled). +# +# Sample syntax (see Documentation/kbuild/makefiles.rst for reference) +# hostprogs := bin2hex +# Will compile bin2hex.c and create an executable named bin2hex +# +# hostprogs := lxdialog +# lxdialog-objs := checklist.o lxdialog.o +# Will compile lxdialog.c and checklist.c, and then link the executable +# lxdialog, based on checklist.o and lxdialog.o +# +# hostprogs := qconf +# qconf-cxxobjs := qconf.o +# qconf-objs := menu.o +# Will compile qconf as a C++ program, and menu as a C program. +# They are linked as C++ code to the executable qconf +# +# hostprogs := target +# target-rust := y +# Will compile `target` as a Rust program, using `target.rs` as the crate root. +# The crate may consist of several source files. + +# C code +# Executables compiled from a single .c file +host-csingle := $(foreach m,$(hostprogs), \ + $(if $($(m)-objs)$($(m)-cxxobjs)$($(m)-rust),,$(m))) + +# C executables linked based on several .o files +host-cmulti := $(foreach m,$(hostprogs),\ + $(if $($(m)-cxxobjs)$($(m)-rust),,$(if $($(m)-objs),$(m)))) + +# Object (.o) files compiled from .c files +host-cobjs := $(sort $(foreach m,$(hostprogs),$($(m)-objs))) + +# C++ code +# C++ executables compiled from at least one .cc file +# and zero or more .c files +host-cxxmulti := $(foreach m,$(hostprogs),$(if $($(m)-cxxobjs),$(m))) + +# C++ Object (.o) files compiled from .cc files +host-cxxobjs := $(sort $(foreach m,$(host-cxxmulti),$($(m)-cxxobjs))) + +# Rust code +# Executables compiled from a single Rust crate (which may consist of +# one or more .rs files) +host-rust := $(foreach m,$(hostprogs),$(if $($(m)-rust),$(m))) + +host-csingle := $(addprefix $(obj)/,$(host-csingle)) +host-cmulti := $(addprefix $(obj)/,$(host-cmulti)) +host-cobjs := $(addprefix $(obj)/,$(host-cobjs)) +host-cxxmulti := $(addprefix $(obj)/,$(host-cxxmulti)) +host-cxxobjs := $(addprefix $(obj)/,$(host-cxxobjs)) +host-rust := $(addprefix $(obj)/,$(host-rust)) + +##### +# Handle options to gcc. Support building with separate output directory + +hostc_flags = -Wp,-MMD,$(depfile) \ + $(KBUILD_HOSTCFLAGS) $(HOST_EXTRACFLAGS) \ + $(HOSTCFLAGS_$(target-stem).o) +hostcxx_flags = -Wp,-MMD,$(depfile) \ + $(KBUILD_HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \ + $(HOSTCXXFLAGS_$(target-stem).o) + +# `--out-dir` is required to avoid temporaries being created by `rustc` in the +# current working directory, which may be not accessible in the out-of-tree +# modules case. +hostrust_flags = --out-dir $(dir $@) --emit=dep-info=$(depfile) \ + -Clinker-flavor=gcc -Clinker=$(HOSTCC) \ + -Clink-args='$(call escsq,$(KBUILD_HOSTLDFLAGS))' \ + $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \ + $(HOSTRUSTFLAGS_$(target-stem)) + +# $(obj) for including generated headers from checkin source files +ifdef building_out_of_srctree +hostc_flags += -I $(obj) +hostcxx_flags += -I $(obj) +endif + +##### +# Compile programs on the host + +# Create executable from a single .c file +# host-csingle -> Executable +quiet_cmd_host-csingle = HOSTCC $@ + cmd_host-csingle = $(HOSTCC) $(hostc_flags) $(KBUILD_HOSTLDFLAGS) -o $@ $< \ + $(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$(target-stem)) +$(host-csingle): $(obj)/%: $(obj)/%.c FORCE + $(call if_changed_dep,host-csingle) + +# Link an executable based on list of .o files, all plain c +# host-cmulti -> executable +quiet_cmd_host-cmulti = HOSTLD $@ + cmd_host-cmulti = $(HOSTCC) $(KBUILD_HOSTLDFLAGS) -o $@ \ + $(addprefix $(obj)/, $($(target-stem)-objs)) \ + $(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$(target-stem)) +$(host-cmulti): FORCE + $(call if_changed,host-cmulti) +$(call multi_depend, $(host-cmulti), , -objs) + +# Create .o file from a single .c file +# host-cobjs -> .o +quiet_cmd_host-cobjs = HOSTCC $@ + cmd_host-cobjs = $(HOSTCC) $(hostc_flags) -c -o $@ $< +$(host-cobjs): $(obj)/%.o: $(obj)/%.c FORCE + $(call if_changed_dep,host-cobjs) + +# Link an executable based on list of .o files, a mixture of .c and .cc +# host-cxxmulti -> executable +quiet_cmd_host-cxxmulti = HOSTLD $@ + cmd_host-cxxmulti = $(HOSTCXX) $(KBUILD_HOSTLDFLAGS) -o $@ \ + $(foreach o,objs cxxobjs,\ + $(addprefix $(obj)/, $($(target-stem)-$(o)))) \ + $(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$(target-stem)) +$(host-cxxmulti): FORCE + $(call if_changed,host-cxxmulti) +$(call multi_depend, $(host-cxxmulti), , -objs -cxxobjs) + +# Create .o file from a single .cc (C++) file +quiet_cmd_host-cxxobjs = HOSTCXX $@ + cmd_host-cxxobjs = $(HOSTCXX) $(hostcxx_flags) -c -o $@ $< +$(host-cxxobjs): $(obj)/%.o: $(obj)/%.cc FORCE + $(call if_changed_dep,host-cxxobjs) + +# Create executable from a single Rust crate (which may consist of +# one or more `.rs` files) +# host-rust -> Executable +quiet_cmd_host-rust = HOSTRUSTC $@ + cmd_host-rust = \ + $(HOSTRUSTC) $(hostrust_flags) --emit=link=$@ $< +$(host-rust): $(obj)/%: $(src)/%.rs FORCE + +$(call if_changed_dep,host-rust) + +targets += $(host-csingle) $(host-cmulti) $(host-cobjs) \ + $(host-cxxmulti) $(host-cxxobjs) $(host-rust) + +# %.lex.o <- %.lex.c <- %.l +# %.tab.o <- %.tab.[ch] <- %.y +targets += $(call intermediate_targets, .lex.o, .lex.c) \ + $(call intermediate_targets, .tab.o, .tab.c .tab.h) -- cgit v1.3.1