On Fri, Jan 15, 2021 at 05:18:30PM +0000, Elena Petrova wrote:
> From: George-Aurelian Popescu <georgepope@xxxxxxxxxx>
>
> Test the UBsan functionality inside hyp/nVHE.
> Because modules are not supported inside of hyp/nVHE code, the default
> testing module for UBSan can not be used.
> New functions have to be defined inside of hyp/nVHE.
> They are called in kvm_get_mdcr_el2, to test UBSAN whenever a VM starts.
>
> Signed-off-by: Elena Petrova <lenaptr@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/assembler.h | 17 ++-
> arch/arm64/include/asm/kvm_debug_buffer.h | 10 +-
> arch/arm64/include/asm/kvm_ubsan.h | 2 +-
> arch/arm64/kvm/hyp/include/hyp/test_ubsan.h | 112 ++++++++++++++++++++
> arch/arm64/kvm/hyp/nvhe/hyp-main.c | 3 +
> arch/arm64/kvm/kvm_ubsan_buffer.c | 1 -
> 6 files changed, 128 insertions(+), 17 deletions(-)
> create mode 100644 arch/arm64/kvm/hyp/include/hyp/test_ubsan.h
>
> diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
> index ebc18a8a0e1f..8422b0d925e8 100644
> --- a/arch/arm64/include/asm/assembler.h
> +++ b/arch/arm64/include/asm/assembler.h
> @@ -259,16 +259,15 @@ alternative_endif
> .endm
>
> /*
> - * @sym: The name of the per-cpu variable
> - * @reg: value to store
> - * @tmp1: scratch register
> - * @tmp2: scratch register
> - */
> - .macro str_this_cpu sym, reg, tmp1, tmp2
> - adr_this_cpu \tmp1, \sym, \tmp2
> + * @sym: The name of the per-cpu variable
> + * @reg: value to store
> + * @tmp1: scratch register
> + * @tmp2: scratch register
> + */
> + .macro str_this_cpu sym, reg, tmp1, tmp2
> + adr_this_cpu \tmp1, \sym, \tmp2
> str \reg, [\tmp1]
> - .endm
> -
> + .endm
> /*
> * vma_vm_mm - get mm pointer from vma pointer (vma->vm_mm)
> */
> diff --git a/arch/arm64/include/asm/kvm_debug_buffer.h b/arch/arm64/include/asm/kvm_debug_buffer.h
> index e5375c2cff1a..361b473bb004 100644
> --- a/arch/arm64/include/asm/kvm_debug_buffer.h
> +++ b/arch/arm64/include/asm/kvm_debug_buffer.h
> @@ -3,10 +3,8 @@
> * Copyright 2020 Google LLC
> * Author: George Popescu <georgepope@xxxxxxxxxx>
> */
> -
> #include <linux/percpu-defs.h>
>
> -
> #define KVM_DEBUG_BUFFER_SIZE 1000
>
> #ifdef __KVM_NVHE_HYPERVISOR__
> @@ -20,17 +18,17 @@
> #else
> #define DECLARE_KVM_DEBUG_BUFFER(type_name, buffer_name, write_ind, size)\
> DECLARE_KVM_NVHE_PER_CPU(type_name, buffer_name)[size]; \
> - DECLARE_KVM_NVHE_PER_CPU(unsigned long, write_ind);
> + DECLARE_KVM_NVHE_PER_CPU(unsigned long, write_ind);
> #endif //__KVM_NVHE_HYPERVISOR__
>
> #ifdef __ASSEMBLY__
> #include <asm/assembler.h>
>
> .macro clear_buffer tmp1, tmp2, tmp3
> - mov \tmp1, 0
> + mov \tmp1, 0
> #ifdef CONFIG_UBSAN
> - str_this_cpu kvm_ubsan_buff_wr_ind, \tmp1, \tmp2, \tmp3
> + str_this_cpu kvm_ubsan_buff_wr_ind, \tmp1, \tmp2, \tmp3
> #endif //CONFIG_UBSAN
> .endm
Are these fixing formatting? If so, move it to the patch that introduced this.
>
> -#endif
> \ No newline at end of file
> +#endif
> diff --git a/arch/arm64/include/asm/kvm_ubsan.h b/arch/arm64/include/asm/kvm_ubsan.h
> index da4a3b4e28e0..0b8bed08d48e 100644
> --- a/arch/arm64/include/asm/kvm_ubsan.h
> +++ b/arch/arm64/include/asm/kvm_ubsan.h
> @@ -9,7 +9,6 @@
> #define UBSAN_MAX_TYPE 6
> #define KVM_UBSAN_BUFFER_SIZE 1000
>
> -
ditto
> struct ubsan_values {
> void *lval;
> void *rval;
> @@ -18,6 +17,7 @@ struct ubsan_values {
>
> struct kvm_ubsan_info {
> enum {
> + UBSAN_NONE,
This also looks like it should have been in a previous patch. The code assumes
that 'type == 0' means 'empty slot'. So presumably this is fixing a bug?
> UBSAN_OUT_OF_BOUNDS,
> UBSAN_UNREACHABLE_DATA,
> UBSAN_SHIFT_OUT_OF_BOUNDS,
> diff --git a/arch/arm64/kvm/hyp/include/hyp/test_ubsan.h b/arch/arm64/kvm/hyp/include/hyp/test_ubsan.h
> new file mode 100644
> index 000000000000..07759c0d1e0e
> --- /dev/null
> +++ b/arch/arm64/kvm/hyp/include/hyp/test_ubsan.h
> @@ -0,0 +1,112 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +
> +#include <linux/ctype.h>
> +
> +typedef void(*test_ubsan_fp)(void);
> +
> +static void test_ubsan_add_overflow(void)
> +{
> + volatile int val = INT_MAX;
> +
> + val += 2;
> +}
> +
> +static void test_ubsan_sub_overflow(void)
> +{
> + volatile int val = INT_MIN;
> + volatile int val2 = 2;
> +
> + val -= val2;
> +}
> +
> +static void test_ubsan_mul_overflow(void)
> +{
> + volatile int val = INT_MAX / 2;
> +
> + val *= 3;
> +}
> +
> +static void test_ubsan_negate_overflow(void)
> +{
> + volatile int val = INT_MIN;
> +
> + val = -val;
> +}
> +
> +static void test_ubsan_divrem_overflow(void)
> +{
> + volatile int val = 16;
> + volatile int val2 = 0;
> +
> + val /= val2;
> +}
> +
> +static void test_ubsan_shift_out_of_bounds(void)
> +{
> + volatile int val = -1;
> + int val2 = 10;
> +
> + val2 <<= val;
> +}
> +
> +static void test_ubsan_out_of_bounds(void)
> +{
> + volatile int i = 4, j = 5;
> + volatile int arr[4];
> +
> + arr[j] = i;
> +}
> +
> +static void test_ubsan_load_invalid_value(void)
> +{
> + volatile char *dst, *src;
> + bool val, val2, *ptr;
> + char c = 4;
> +
> + dst = (char *)&val;
> + src = &c;
> + *dst = *src;
> +
> + ptr = &val2;
> + val2 = val;
> +}
> +
> +static void test_ubsan_misaligned_access(void)
> +{
> + volatile char arr[5] __aligned(4) = {1, 2, 3, 4, 5};
> + volatile int *ptr, val = 6;
> +
> + ptr = (int *)(arr + 1);
> + *ptr = val;
> +}
> +
> +static void test_ubsan_object_size_mismatch(void)
> +{
> + /* "((aligned(8)))" helps this not into be misaligned for ptr-access. */
> + volatile int val __aligned(8) = 4;
> + volatile long long *ptr, val2;
> +
> + ptr = (long long *)&val;
> + val2 = *ptr;
> +}
> +
> +static const test_ubsan_fp test_ubsan_array[] = {
> + test_ubsan_out_of_bounds,
> + test_ubsan_add_overflow,
> + test_ubsan_sub_overflow,
> + test_ubsan_mul_overflow,
> + test_ubsan_negate_overflow,
> + test_ubsan_divrem_overflow,
> + test_ubsan_shift_out_of_bounds,
> + test_ubsan_load_invalid_value,
> + test_ubsan_misaligned_access,
> + test_ubsan_object_size_mismatch,
> +};
> +
> +static void test_ubsan(void)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < ARRAY_SIZE(test_ubsan_array); i++)
> + test_ubsan_array[i]();
> +}
> diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> index a906f9e2ff34..939600e9fdd6 100644
> --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> @@ -13,6 +13,7 @@
> #include <asm/kvm_mmu.h>
>
> #include <nvhe/trap_handler.h>
> +#include <hyp/test_ubsan.h>
>
> DEFINE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);
>
> @@ -90,6 +91,8 @@ static void handle___vgic_v3_init_lrs(struct kvm_cpu_context *host_ctxt)
> static void handle___kvm_get_mdcr_el2(struct kvm_cpu_context *host_ctxt)
> {
> cpu_reg(host_ctxt, 1) = __kvm_get_mdcr_el2();
> + if (IS_ENABLED(CONFIG_TEST_UBSAN))
> + test_ubsan();
> }
We cannot keep this in here. It's useful to exercise your code in development
but not something you should upstream. I would either remove this completely or
implement it as a separate hypercall.
>
> static void handle___vgic_v3_save_aprs(struct kvm_cpu_context *host_ctxt)
> diff --git a/arch/arm64/kvm/kvm_ubsan_buffer.c b/arch/arm64/kvm/kvm_ubsan_buffer.c
> index 2c7060cbb48b..49bedc9de139 100644
> --- a/arch/arm64/kvm/kvm_ubsan_buffer.c
> +++ b/arch/arm64/kvm/kvm_ubsan_buffer.c
> @@ -11,7 +11,6 @@
> #include <asm/kvm_asm.h>
> #include <kvm/arm_pmu.h>
>
> -#include <ubsan.h>
ditto
> #include <asm/kvm_ubsan.h>
>
> DECLARE_KVM_DEBUG_BUFFER(struct kvm_ubsan_info, kvm_ubsan_buffer,
> --
> 2.30.0.296.g2bfb1c46d8-goog
>
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