From: Mostafa Saleh Date: Wed, 30 Apr 2025 16:27:10 +0000 (+0000) Subject: KVM: arm64: Introduce CONFIG_UBSAN_KVM_EL2 X-Git-Tag: v6.16-rc1~78^2^2~13^2~1 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=61b38f7591fb434fce326c1d686a9793c7f418bc;p=linux-block.git KVM: arm64: Introduce CONFIG_UBSAN_KVM_EL2 Add a new Kconfig CONFIG_UBSAN_KVM_EL2 for KVM which enables UBSAN for EL2 code (in protected/nvhe/hvhe) modes. This will re-use the same checks enabled for the kernel for the hypervisor. The only difference is that for EL2 it always emits a "brk" instead of implementing hooks as the hypervisor can't print reports. The KVM code will re-use the same code for the kernel "report_ubsan_failure()" so #ifdefs are changed to also have this code for CONFIG_UBSAN_KVM_EL2 Signed-off-by: Mostafa Saleh Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20250430162713.1997569-4-smostafa@google.com Signed-off-by: Marc Zyngier --- diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile index b43426a493df..a76522d63c3e 100644 --- a/arch/arm64/kvm/hyp/nvhe/Makefile +++ b/arch/arm64/kvm/hyp/nvhe/Makefile @@ -99,3 +99,9 @@ KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS), $(KBUILD_CFLAG # causes a build failure. Remove profile optimization flags. KBUILD_CFLAGS := $(filter-out -fprofile-sample-use=% -fprofile-use=%, $(KBUILD_CFLAGS)) KBUILD_CFLAGS += -fno-asynchronous-unwind-tables -fno-unwind-tables + +ifeq ($(CONFIG_UBSAN_KVM_EL2),y) +UBSAN_SANITIZE := y +# Always use brk and not hooks +ccflags-y += $(CFLAGS_UBSAN_TRAP) +endif diff --git a/include/linux/ubsan.h b/include/linux/ubsan.h index c843816f5f68..3ab8d38aedb8 100644 --- a/include/linux/ubsan.h +++ b/include/linux/ubsan.h @@ -2,7 +2,7 @@ #ifndef _LINUX_UBSAN_H #define _LINUX_UBSAN_H -#ifdef CONFIG_UBSAN_TRAP +#if defined(CONFIG_UBSAN_TRAP) || defined(CONFIG_UBSAN_KVM_EL2) const char *report_ubsan_failure(u32 check_type); #else static inline const char *report_ubsan_failure(u32 check_type) diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan index f6ea0c5b5da3..42ed41804644 100644 --- a/lib/Kconfig.ubsan +++ b/lib/Kconfig.ubsan @@ -165,4 +165,13 @@ config TEST_UBSAN This is a test module for UBSAN. It triggers various undefined behavior, and detect it. +config UBSAN_KVM_EL2 + bool "UBSAN for KVM code at EL2" + depends on ARM64 + help + Enable UBSAN when running on ARM64 with KVM in a split mode + (nvhe/hvhe/protected) for the hypervisor code running in EL2. + In this mode, any UBSAN violation in EL2 would panic the kernel + and information similar to UBSAN_TRAP would be printed. + endif # if UBSAN diff --git a/lib/ubsan.c b/lib/ubsan.c index 17993727fc96..a6ca235dd714 100644 --- a/lib/ubsan.c +++ b/lib/ubsan.c @@ -19,7 +19,7 @@ #include "ubsan.h" -#ifdef CONFIG_UBSAN_TRAP +#if defined(CONFIG_UBSAN_TRAP) || defined(CONFIG_UBSAN_KVM_EL2) /* * Only include matches for UBSAN checks that are actually compiled in. * The mappings of struct SanitizerKind (the -fsanitize=xxx args) to @@ -97,7 +97,9 @@ const char *report_ubsan_failure(u32 check_type) } } -#else +#endif + +#ifndef CONFIG_UBSAN_TRAP static const char * const type_check_kinds[] = { "load of", "store to", diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan index 9e35198edbf0..73c7a9be0796 100644 --- a/scripts/Makefile.ubsan +++ b/scripts/Makefile.ubsan @@ -1,5 +1,8 @@ # SPDX-License-Identifier: GPL-2.0 +# Shared with KVM/arm64. +export CFLAGS_UBSAN_TRAP := $(call cc-option,-fsanitize-trap=undefined,-fsanitize-undefined-trap-on-error) + # Enable available and selected UBSAN features. ubsan-cflags-$(CONFIG_UBSAN_ALIGNMENT) += -fsanitize=alignment ubsan-cflags-$(CONFIG_UBSAN_BOUNDS_STRICT) += -fsanitize=bounds-strict @@ -10,7 +13,7 @@ ubsan-cflags-$(CONFIG_UBSAN_DIV_ZERO) += -fsanitize=integer-divide-by-zero ubsan-cflags-$(CONFIG_UBSAN_UNREACHABLE) += -fsanitize=unreachable ubsan-cflags-$(CONFIG_UBSAN_BOOL) += -fsanitize=bool ubsan-cflags-$(CONFIG_UBSAN_ENUM) += -fsanitize=enum -ubsan-cflags-$(CONFIG_UBSAN_TRAP) += $(call cc-option,-fsanitize-trap=undefined,-fsanitize-undefined-trap-on-error) +ubsan-cflags-$(CONFIG_UBSAN_TRAP) += $(CFLAGS_UBSAN_TRAP) export CFLAGS_UBSAN := $(ubsan-cflags-y)