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This is unsafe for production. In preparation for adding more debug options to NVHE_EL2_DEBUG, decouple the stage-2 relaxation into a separate option. While at it, rename PROTECTED_NVHE_STACKTRACE into PKVM_STACKTRACE, following the same naming scheme as PKVM_DISABLE_STAGE2_ON_PANIC. Reviewed-by: Kalesh Singh Signed-off-by: Vincent Donnefort diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 7d1f22fd490b..14b2d0b0b831 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -42,9 +42,27 @@ menuconfig KVM =20 If unsure, say N. =20 +if KVM + +config PTDUMP_STAGE2_DEBUGFS + bool "Present the stage-2 pagetables to debugfs" + depends on DEBUG_KERNEL + depends on DEBUG_FS + depends on ARCH_HAS_PTDUMP + select PTDUMP + default n + help + Say Y here if you want to show the stage-2 kernel pagetables + layout in a debugfs file. This information is only useful for kernel de= velopers + who are working in architecture specific areas of the kernel. + It is probably not a good idea to enable this feature in a production + kernel. + + If in doubt, say N. + config NVHE_EL2_DEBUG bool "Debug mode for non-VHE EL2 object" - depends on KVM + default n help Say Y here to enable the debug mode for the non-VHE KVM EL2 object. Failure reports will BUG() in the hypervisor. This is intended for @@ -52,10 +70,23 @@ config NVHE_EL2_DEBUG =20 If unsure, say N. =20 -config PROTECTED_NVHE_STACKTRACE - bool "Protected KVM hypervisor stacktraces" - depends on NVHE_EL2_DEBUG +if NVHE_EL2_DEBUG + +config PKVM_DISABLE_STAGE2_ON_PANIC + bool "Disable the host stage-2 on panic" default n + help + Relax the host stage-2 on hypervisor panic to allow the kernel to + unwind and symbolize the hypervisor stacktrace. This however tampers + the system security. This is intended for local EL2 hypervisor + development. + + If unsure, say N. + +config PKVM_STACKTRACE + bool "Protected KVM hypervisor stacktraces" + depends on PKVM_DISABLE_STAGE2_ON_PANIC + default y help Say Y here to enable pKVM hypervisor stacktraces on hyp_panic() =20 @@ -65,21 +96,6 @@ config PROTECTED_NVHE_STACKTRACE =20 If unsure, or not using protected nVHE (pKVM), say N. =20 -config PTDUMP_STAGE2_DEBUGFS - bool "Present the stage-2 pagetables to debugfs" - depends on KVM - depends on DEBUG_KERNEL - depends on DEBUG_FS - depends on ARCH_HAS_PTDUMP - select PTDUMP - default n - help - Say Y here if you want to show the stage-2 kernel pagetables - layout in a debugfs file. This information is only useful for kernel de= velopers - who are working in architecture specific areas of the kernel. - It is probably not a good idea to enable this feature in a production - kernel. - - If in doubt, say N. - +endif # NVHE_EL2_DEBUG +endif # KVM endif # VIRTUALIZATION diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index cc7d5d1709cb..54aedf93c78b 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -539,7 +539,7 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, = u64 spsr, =20 /* All hyp bugs, including warnings, are treated as fatal. */ if (!is_protected_kvm_enabled() || - IS_ENABLED(CONFIG_NVHE_EL2_DEBUG)) { + IS_ENABLED(CONFIG_PKVM_DISABLE_STAGE2_ON_PANIC)) { struct bug_entry *bug =3D find_bug(elr_in_kimg); =20 if (bug) diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S index eef15b374abb..3092befcd97c 100644 --- a/arch/arm64/kvm/hyp/nvhe/host.S +++ b/arch/arm64/kvm/hyp/nvhe/host.S @@ -120,7 +120,7 @@ SYM_FUNC_START(__hyp_do_panic) =20 mov x29, x0 =20 -#ifdef CONFIG_NVHE_EL2_DEBUG +#ifdef PKVM_DISABLE_STAGE2_ON_PANIC /* Ensure host stage-2 is disabled */ mrs x0, hcr_el2 bic x0, x0, #HCR_VM diff --git a/arch/arm64/kvm/hyp/nvhe/stacktrace.c b/arch/arm64/kvm/hyp/nvhe= /stacktrace.c index 5b6eeab1a774..7c832d60d22b 100644 --- a/arch/arm64/kvm/hyp/nvhe/stacktrace.c +++ b/arch/arm64/kvm/hyp/nvhe/stacktrace.c @@ -34,7 +34,7 @@ static void hyp_prepare_backtrace(unsigned long fp, unsig= ned long pc) stacktrace_info->pc =3D pc; } =20 -#ifdef CONFIG_PROTECTED_NVHE_STACKTRACE +#ifdef CONFIG_PKVM_STACKTRACE #include =20 DEFINE_PER_CPU(unsigned long [NVHE_STACKTRACE_SIZE/sizeof(long)], pkvm_sta= cktrace); @@ -134,11 +134,11 @@ static void pkvm_save_backtrace(unsigned long fp, uns= igned long pc) =20 unwind(&state, pkvm_save_backtrace_entry, &idx); } -#else /* !CONFIG_PROTECTED_NVHE_STACKTRACE */ +#else /* !CONFIG_PKVM_STACKTRACE */ static void pkvm_save_backtrace(unsigned long fp, unsigned long pc) { } -#endif /* CONFIG_PROTECTED_NVHE_STACKTRACE */ +#endif /* CONFIG_PKVM_STACKTRACE */ =20 /* * kvm_nvhe_prepare_backtrace - prepare to dump the nVHE backtrace diff --git a/arch/arm64/kvm/stacktrace.c b/arch/arm64/kvm/stacktrace.c index af5eec681127..9724c320126b 100644 --- a/arch/arm64/kvm/stacktrace.c +++ b/arch/arm64/kvm/stacktrace.c @@ -197,7 +197,7 @@ static void hyp_dump_backtrace(unsigned long hyp_offset) kvm_nvhe_dump_backtrace_end(); } =20 -#ifdef CONFIG_PROTECTED_NVHE_STACKTRACE +#ifdef CONFIG_PKVM_STACKTRACE DECLARE_KVM_NVHE_PER_CPU(unsigned long [NVHE_STACKTRACE_SIZE/sizeof(long)], pkvm_stacktrace); =20 @@ -225,12 +225,12 @@ static void pkvm_dump_backtrace(unsigned long hyp_off= set) kvm_nvhe_dump_backtrace_entry((void *)hyp_offset, stacktrace[i]); kvm_nvhe_dump_backtrace_end(); } -#else /* !CONFIG_PROTECTED_NVHE_STACKTRACE */ +#else /* !CONFIG_PKVM_STACKTRACE */ static void pkvm_dump_backtrace(unsigned long hyp_offset) { - kvm_err("Cannot dump pKVM nVHE stacktrace: !CONFIG_PROTECTED_NVHE_STACKTR= ACE\n"); + kvm_err("Cannot dump pKVM nVHE stacktrace: !CONFIG_PKVM_STACKTRACE\n"); } -#endif /* CONFIG_PROTECTED_NVHE_STACKTRACE */ +#endif /* CONFIG_PKVM_STACKTRACE */ =20 /* * kvm_nvhe_dump_backtrace - Dump KVM nVHE hypervisor backtrace. --=20 2.53.0.473.g4a7958ca14-goog