| Message ID | 20200515105841.73532-5-dbrazdil@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Split off nVHE hyp code | expand |
On Fri, May 15, 2020 at 11:58:31AM +0100, David Brazdil wrote: > diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h > index 7f06ad93fc95..13850134fc28 100644 > --- a/arch/arm64/kernel/image-vars.h > +++ b/arch/arm64/kernel/image-vars.h > @@ -51,4 +51,16 @@ __efistub__ctype = _ctype; > > #endif > > +#ifdef CONFIG_KVM > + > +/* > + * KVM nVHE code has its own symbol namespace prefixed by __hyp_text_, to > + * isolate it from the kernel proper. The following symbols are legally > + * accessed by it, therefore provide aliases to make them linkable. > + * Do not include symbols which may not be safely accessed under hypervisor > + * memory mappings. > + */ nit: the prefix is not '__kvm_nvhe_' rather than '__hyp_text_'
On Mon, May 18, 2020 at 04:55:53PM +0100, Andrew Scull wrote: > On Fri, May 15, 2020 at 11:58:31AM +0100, David Brazdil wrote: > > diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h > > index 7f06ad93fc95..13850134fc28 100644 > > --- a/arch/arm64/kernel/image-vars.h > > +++ b/arch/arm64/kernel/image-vars.h > > @@ -51,4 +51,16 @@ __efistub__ctype = _ctype; > > > > #endif > > > > +#ifdef CONFIG_KVM > > + > > +/* > > + * KVM nVHE code has its own symbol namespace prefixed by __hyp_text_, to > > + * isolate it from the kernel proper. The following symbols are legally > > + * accessed by it, therefore provide aliases to make them linkable. > > + * Do not include symbols which may not be safely accessed under hypervisor > > + * memory mappings. > > + */ > > nit: the prefix is not '__kvm_nvhe_' rather than '__hyp_text_' Thanks, will fix in v3.
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index 7f06ad93fc95..13850134fc28 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -51,4 +51,16 @@ __efistub__ctype = _ctype; #endif +#ifdef CONFIG_KVM + +/* + * KVM nVHE code has its own symbol namespace prefixed by __hyp_text_, to + * isolate it from the kernel proper. The following symbols are legally + * accessed by it, therefore provide aliases to make them linkable. + * Do not include symbols which may not be safely accessed under hypervisor + * memory mappings. + */ + +#endif /* CONFIG_KVM */ + #endif /* __ARM64_KERNEL_IMAGE_VARS_H */ diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile index 5d8357ddc234..c9fd8618980d 100644 --- a/arch/arm64/kvm/hyp/Makefile +++ b/arch/arm64/kvm/hyp/Makefile @@ -6,10 +6,10 @@ ccflags-y += -fno-stack-protector -DDISABLE_BRANCH_PROFILING \ $(DISABLE_STACKLEAK_PLUGIN) -obj-$(CONFIG_KVM) += hyp.o +obj-$(CONFIG_KVM) += vhe.o nvhe/ obj-$(CONFIG_KVM_INDIRECT_VECTORS) += smccc_wa.o -hyp-y := vgic-v3-sr.o timer-sr.o aarch32.o vgic-v2-cpuif-proxy.o sysreg-sr.o \ +vhe-y := vgic-v3-sr.o timer-sr.o aarch32.o vgic-v2-cpuif-proxy.o sysreg-sr.o \ debug-sr.o entry.o switch.o fpsimd.o tlb.o hyp-entry.o # KVM code is run at a different exception code with a different map, so diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile new file mode 100644 index 000000000000..7d64235dba62 --- /dev/null +++ b/arch/arm64/kvm/hyp/nvhe/Makefile @@ -0,0 +1,35 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for Kernel-based Virtual Machine module, HYP/nVHE part +# + +asflags-y := -D__KVM_NVHE_HYPERVISOR__ +ccflags-y := -D__KVM_NVHE_HYPERVISOR__ -fno-stack-protector \ + -DDISABLE_BRANCH_PROFILING $(DISABLE_STACKLEAK_PLUGIN) + +obj-y := + +obj-y := $(patsubst %.o,%.hyp.o,$(obj-y)) +extra-y := $(patsubst %.hyp.o,%.hyp.tmp.o,$(obj-y)) + +$(obj)/%.hyp.tmp.o: $(src)/%.c FORCE + $(call if_changed_rule,cc_o_c) +$(obj)/%.hyp.tmp.o: $(src)/%.S FORCE + $(call if_changed_rule,as_o_S) +$(obj)/%.hyp.o: $(obj)/%.hyp.tmp.o FORCE + $(call if_changed,hypcopy) + +quiet_cmd_hypcopy = HYPCOPY $@ + cmd_hypcopy = $(OBJCOPY) --prefix-symbols=__kvm_nvhe_ $< $@ + +# KVM nVHE code is run at a different exception code with a different map, so +# compiler instrumentation that inserts callbacks or checks into the code may +# cause crashes. Just disable it. +GCOV_PROFILE := n +KASAN_SANITIZE := n +UBSAN_SANITIZE := n +KCOV_INSTRUMENT := n + +# Skip objtool checking for this directory because nVHE code is compiled with +# non-standard build rules. +OBJECT_FILES_NON_STANDARD := y diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 3e8dea6e0a95..523a1a337ebd 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -109,6 +109,7 @@ static bool is_ignored_symbol(const char *name, char type) ".LASANPC", /* s390 kasan local symbols */ "__crc_", /* modversions */ "__efistub_", /* arm64 EFI stub namespace */ + "__kvm_nvhe_", /* arm64 non-VHE KVM namespace */ NULL };
Add new folder arch/arm64/kvm/hyp/nvhe and a Makefile for building code that runs in EL2 under nVHE KVM. Compile each source file into a `.hyp.tmp.o` object first, then prefix all its symbols with "__kvm_nvhe_" using `objcopy` and produce a `.hyp.o`. Suffixes were chosen so that it would be possible for VHE and nVHE to share some source files, but compiled with different CFLAGS. nVHE build rules add -D__KVM_NVHE_HYPERVISOR__. The nVHE ELF symbol prefix is added to kallsyms.c as ignored. EL2-only symbols will never appear in EL1 stack traces. Signed-off-by: David Brazdil <dbrazdil@google.com> --- arch/arm64/kernel/image-vars.h | 12 +++++++++++ arch/arm64/kvm/hyp/Makefile | 4 ++-- arch/arm64/kvm/hyp/nvhe/Makefile | 35 ++++++++++++++++++++++++++++++++ scripts/kallsyms.c | 1 + 4 files changed, 50 insertions(+), 2 deletions(-) create mode 100644 arch/arm64/kvm/hyp/nvhe/Makefile