[PATCH v2 3/3] RISC-V: KVM: selftests: Add breakpoints test support

[Anup Patel]

This is actually a ebreak test so subject should be:
"RISC-V: KVM: selftests: Add ebreak test support"

On Fri, Mar 1, 2024 at 7:08 AM Chao Du <duchao at eswincomputing.com> wrote:
>
> Initial support for RISC-V KVM breakpoint test. Check the exit reason
> and the PC when guest debug is enabled.

s/breakpoint/ebreak/

>
> Signed-off-by: Chao Du <duchao at eswincomputing.com>
> ---
>  tools/testing/selftests/kvm/Makefile          |  1 +
>  .../testing/selftests/kvm/riscv/breakpoints.c | 49 +++++++++++++++++++

Rename riscv/breakpoints.c to riscv/ebreak_test.c

>  2 files changed, 50 insertions(+)
>  create mode 100644 tools/testing/selftests/kvm/riscv/breakpoints.c
>
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index 492e937fab00..5f9048a740b0 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -184,6 +184,7 @@ TEST_GEN_PROGS_s390x += rseq_test
>  TEST_GEN_PROGS_s390x += set_memory_region_test
>  TEST_GEN_PROGS_s390x += kvm_binary_stats_test
>
> +TEST_GEN_PROGS_riscv += riscv/breakpoints
>  TEST_GEN_PROGS_riscv += demand_paging_test
>  TEST_GEN_PROGS_riscv += dirty_log_test
>  TEST_GEN_PROGS_riscv += get-reg-list
> diff --git a/tools/testing/selftests/kvm/riscv/breakpoints.c b/tools/testing/selftests/kvm/riscv/breakpoints.c
> new file mode 100644
> index 000000000000..be2d94837c83
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/riscv/breakpoints.c
> @@ -0,0 +1,49 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * RISC-V KVM breakpoint tests.

s/breakpoint tests/ebreak test/

> + *
> + * Copyright 2024 Beijing ESWIN Computing Technology Co., Ltd.
> + *
> + */
> +#include "kvm_util.h"
> +
> +#define PC(v) ((uint64_t)&(v))
> +
> +extern unsigned char sw_bp;
> +
> +static void guest_code(void)
> +{
> +       asm volatile("sw_bp: ebreak");
> +       asm volatile("nop");
> +       asm volatile("nop");
> +       asm volatile("nop");
> +
> +       GUEST_DONE();
> +}
> +
> +int main(void)
> +{
> +       struct kvm_vm *vm;
> +       struct kvm_vcpu *vcpu;
> +       struct kvm_guest_debug debug;
> +       uint64_t pc;
> +
> +       TEST_REQUIRE(kvm_has_cap(KVM_CAP_SET_GUEST_DEBUG));
> +
> +       vm = vm_create_with_one_vcpu(&vcpu, guest_code);
> +
> +       memset(&debug, 0, sizeof(debug));
> +       debug.control = KVM_GUESTDBG_ENABLE;
> +       vcpu_guest_debug_set(vcpu, &debug);
> +       vcpu_run(vcpu);
> +
> +       TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_DEBUG);

This is only testing the case where KVM_GUESTDBG_ENABLE is set.

This test should be enhanced to:
1) First test "ebreak" executed by Guest when KVM_GUESTDBG_ENABLE
    is not set. Here, we would expect main() to receive KVM_EXIT_DEBUG.
2) Second test "ebreak" executed by Guest when KVM_GUESTDBG_ENABLE
   is set. Here, we would expect main() will not receive KVM_EXIT_DEBUG.

> +
> +       vcpu_get_reg(vcpu, RISCV_CORE_REG(regs.pc), &pc);
> +
> +       TEST_ASSERT_EQ(pc, PC(sw_bp));
> +
> +       kvm_vm_free(vm);
> +
> +       return 0;
> +}
> --
> 2.17.1
>

Regards,
Anup