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[34.77.222.49]) by smtp.gmail.com with ESMTPSA id s67sm25882497wmf.38.2020.09.15.06.25.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Sep 2020 06:26:00 -0700 (PDT) Date: Tue, 15 Sep 2020 13:25:58 +0000 From: George Popescu To: maz@kernel.org, catalin.marinas@arm.com, will@kernel.org, masahiroy@kernel.org, michal.lkml@markovi.net Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, natechancellor@gmail.com, ndesaulniers@google.com, dbrazdil@google.com, broonie@kernel.org, maskray@google.com, ascull@google.com, keescook@chromium.org, akpm@linux-foundation.org, dvyukov@google.com, elver@google.com, tglx@linutronix.de, arnd@arndb.de Subject: Re: [PATCH 05/14] KVM: arm64: Define a buffer that can pass UBSan data from hyp/nVHE to kernel Message-ID: <20200915132558.GA1948537@google.com> References: <20200914172750.852684-1-georgepope@google.com> <20200914172750.852684-6-georgepope@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200914172750.852684-6-georgepope@google.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 14, 2020 at 05:27:41PM +0000, George-Aurelian Popescu wrote: > From: George Popescu Just realized that with UBSAN disabled this code won't compile. Sorry for that. Had to add the two lines of code below: > Store data, which is collected from UBSan handlers that lives inside hyp/nVHE, > into the kvm_ubsan_buffer. > This buffer is designed to store only UBSan data because it should not be > preoccupied by other mechanisms data structures and functionalities. > > Map the buffer and the write index before switching the control to > hyp/nVHE. > > Map the kernel .data region to read the compile time generated UBSan struct's > data from hyp/nVHE. > > Signed-off-by: George Popescu > --- > arch/arm64/include/asm/kvm_asm.h | 3 +++ > arch/arm64/include/asm/kvm_host.h | 6 +++++ > arch/arm64/include/asm/kvm_ubsan.h | 17 +++++++++++++ > arch/arm64/kvm/Makefile | 4 ++++ > arch/arm64/kvm/arm.c | 38 +++++++++++++++++++++++++++++- > arch/arm64/kvm/hyp/hyp-entry.S | 4 ++++ > arch/arm64/kvm/hyp/nvhe/ubsan.c | 24 ++++++++++++++++++- > arch/arm64/kvm/kvm_ubsan_buffer.c | 32 +++++++++++++++++++++++++ > 8 files changed, 126 insertions(+), 2 deletions(-) > create mode 100644 arch/arm64/include/asm/kvm_ubsan.h > create mode 100644 arch/arm64/kvm/kvm_ubsan_buffer.c > > diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h > index 200bb8d0a720..9d4a77f08ffd 100644 > --- a/arch/arm64/include/asm/kvm_asm.h > +++ b/arch/arm64/include/asm/kvm_asm.h > @@ -63,6 +63,9 @@ > #define CHOOSE_VHE_SYM(sym) sym > #define CHOOSE_NVHE_SYM(sym) kvm_nvhe_sym(sym) > > +#define this_cpu_ptr_nvhe(sym) this_cpu_ptr(&kvm_nvhe_sym(sym)) > +#define per_cpu_ptr_nvhe(sym, cpu) per_cpu_ptr(&kvm_nvhe_sym(sym), cpu) > + > #ifndef __KVM_NVHE_HYPERVISOR__ > /* > * BIG FAT WARNINGS: > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index adc8957e9321..337fd2d0f976 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -494,8 +494,14 @@ u64 __kvm_call_hyp(void *hypfn, ...); > __kvm_call_hyp(kvm_ksym_ref_nvhe(f), ##__VA_ARGS__); \ > }) > > +#ifdef CONFIG_UBSAN > +extern void __kvm_check_ubsan_buffer(void); #else static inline void __kvm_check_ubsan_buffer(void){} > +#endif > + > #define __kvm_arm_check_debug_buffer() \ > { \ > + if (IS_ENABLED(CONFIG_UBSAN)) \ > + __kvm_check_ubsan_buffer(); \ > } > > /* > diff --git a/arch/arm64/include/asm/kvm_ubsan.h b/arch/arm64/include/asm/kvm_ubsan.h > new file mode 100644 > index 000000000000..af607a796376 > --- /dev/null > +++ b/arch/arm64/include/asm/kvm_ubsan.h > @@ -0,0 +1,17 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright 2020 Google LLC > + * Author: George Popescu > + */ > + > +#ifdef CONFIG_UBSAN > +#include > + > + > +#define UBSAN_MAX_TYPE 6 > +#define KVM_UBSAN_BUFFER_SIZE 1000 > + > +struct kvm_ubsan_info { > + int type; > +}; > +#endif > diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile > index 99977c1972cc..92f06cb5b3df 100644 > --- a/arch/arm64/kvm/Makefile > +++ b/arch/arm64/kvm/Makefile > @@ -24,4 +24,8 @@ kvm-y := $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o \ > vgic/vgic-mmio-v3.o vgic/vgic-kvm-device.o \ > vgic/vgic-its.o vgic/vgic-debug.o > > +CFLAGS_kvm_ubsan_buffer.o += -I $(srctree)/lib/ > +CFLAGS_arm.o += -I $(srctree)/lib > + > +kvm-$(CONFIG_UBSAN) += kvm_ubsan_buffer.o > kvm-$(CONFIG_KVM_ARM_PMU) += pmu-emul.o > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index b588c3b5c2f0..eff57069e103 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -42,10 +42,17 @@ > #include > #include > > +#include > +#include > + > #ifdef REQUIRES_VIRT > __asm__(".arch_extension virt"); > #endif > > +#ifdef CONFIG_UBSAN > +DECLARE_KVM_DEBUG_BUFFER(struct kvm_ubsan_info, kvm_ubsan_buff, KVM_UBSAN_BUFFER_SIZE); > +#endif > + > DEFINE_PER_CPU(kvm_host_data_t, kvm_host_data); > static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page); > > @@ -1519,7 +1526,15 @@ static int init_hyp_mode(void) > kvm_err("Cannot map bss section\n"); > goto out_err; > } > - > +#ifdef CONFIG_UBSAN > + /* required by ubsan to access the handlers structures fields */ > + err = create_hyp_mappings(kvm_ksym_ref(_data), > + kvm_ksym_ref(__end_once), PAGE_HYP_RO); > + if (err) { > + kvm_err("Cannot map data section\n"); > + goto out_err; > + } > +#endif > err = kvm_map_vectors(); > if (err) { > kvm_err("Cannot map vectors\n"); > @@ -1552,6 +1567,27 @@ static int init_hyp_mode(void) > } > } > > +#ifdef CONFIG_UBSAN > + for_each_possible_cpu(cpu) { > + /* map the write index */ > + struct kvm_ubsan_info *buff; > + unsigned long *wr_ind; > + > + wr_ind = per_cpu_ptr_nvhe(kvm_ubsan_buff_wr_ind, cpu); > + err = create_hyp_mappings(wr_ind, wr_ind + 1, PAGE_HYP); > + if (err) { > + kvm_err("Cannot map the busan buffer write index: %d\n", err); > + goto out_err; > + } > + buff = per_cpu_ptr(kvm_nvhe_sym(kvm_ubsan_buff), cpu); > + err = create_hyp_mappings(buff, buff + KVM_UBSAN_BUFFER_SIZE, PAGE_HYP); > + if (err) { > + kvm_err("Cannot map the ubsan buffer: %d\n", err); > + goto out_err; > + } > + } > +#endif > + > err = hyp_map_aux_data(); > if (err) > kvm_err("Cannot map host auxiliary data: %d\n", err); > diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S > index 8df0082b9ccf..bcdbab4d2e43 100644 > --- a/arch/arm64/kvm/hyp/hyp-entry.S > +++ b/arch/arm64/kvm/hyp/hyp-entry.S > @@ -14,6 +14,7 @@ > #include > #include > #include > +#include > > .macro save_caller_saved_regs_vect > /* x0 and x1 were saved in the vector entry */ > @@ -74,6 +75,9 @@ el1_sync: // Guest trapped into EL2 > cmp x0, #HVC_STUB_HCALL_NR > b.hs 1f > > +#ifdef CONFIG_UBSAN > + clear_kvm_debug_buffer kvm_ubsan_buff_wr_ind, x4, x5, x6 > +#endif > /* > * Compute the idmap address of __kvm_handle_stub_hvc and > * jump there. Since we use kimage_voffset, do not use the > diff --git a/arch/arm64/kvm/hyp/nvhe/ubsan.c b/arch/arm64/kvm/hyp/nvhe/ubsan.c > index a5db6b61ceb2..a43c9646e1e8 100644 > --- a/arch/arm64/kvm/hyp/nvhe/ubsan.c > +++ b/arch/arm64/kvm/hyp/nvhe/ubsan.c > @@ -3,9 +3,31 @@ > * Copyright 2020 Google LLC > * Author: George Popescu > */ > +#include > #include > #include > -#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +DEFINE_KVM_DEBUG_BUFFER(struct kvm_ubsan_info, kvm_ubsan_buff, KVM_UBSAN_BUFFER_SIZE); > + > +static inline struct kvm_ubsan_info *kvm_ubsan_buffer_next_slot(void) > +{ > + struct kvm_ubsan_info *res; > + struct kvm_ubsan_info *buff; > + unsigned long *buff_ind; > + unsigned long buff_size = KVM_UBSAN_BUFFER_SIZE; > + unsigned int struct_size = sizeof(struct kvm_ubsan_info); > + > + init_kvm_debug_buffer(kvm_ubsan_buff, struct kvm_ubsan_info, buff, buff_ind); > + res = kvm_debug_buffer_next_slot(buff, buff_ind, struct_size, buff_size); > + return res; > +} > > void __ubsan_handle_add_overflow(void *_data, void *lhs, void *rhs) {} > > diff --git a/arch/arm64/kvm/kvm_ubsan_buffer.c b/arch/arm64/kvm/kvm_ubsan_buffer.c > new file mode 100644 > index 000000000000..28dcf19b5706 > --- /dev/null > +++ b/arch/arm64/kvm/kvm_ubsan_buffer.c > @@ -0,0 +1,32 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright 2020 Google LLC > + * Author: George Popescu > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include > +#include > + > +DECLARE_KVM_DEBUG_BUFFER(struct kvm_ubsan_info, kvm_ubsan_buff, KVM_UBSAN_BUFFER_SIZE); > + > + > +void __kvm_check_ubsan_buffer(void) > +{ > + unsigned long *write_ind; > + unsigned long it; > + struct kvm_ubsan_info *slot; > + > + init_kvm_debug_buffer(kvm_ubsan_buff, struct kvm_ubsan_info, slot, write_ind); > + for_each_kvm_debug_buffer_slot(slot, write_ind, it) { > + /* check ubsan data */ > + slot->type = 0; > + } > +} > + > -- > 2.28.0.618.gf4bc123cb7-goog >