Currently, we simply hang using "while (1) ;" upon any unexpected
guest traps because the default guest trap handler is guest_hang().
The above approach is not useful to anyone because KVM selftests
users will only see a hung application upon any unexpected guest
trap.
This patch improves unexpected guest trap handling for KVM RISC-V
selftests by doing the following:
1) Return to host user-space
2) Dump VCPU registers
3) Die using TEST_ASSERT(0, ...)
Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
---
.../selftests/kvm/include/riscv/processor.h | 8 +++--
.../selftests/kvm/lib/riscv/processor.c | 9 +++---
tools/testing/selftests/kvm/lib/riscv/ucall.c | 31 +++++++++++++------
3 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/tools/testing/selftests/kvm/include/riscv/processor.h b/tools/testing/selftests/kvm/include/riscv/processor.h
index eca5c622efd2..4fcfd1c0389d 100644
--- a/tools/testing/selftests/kvm/include/riscv/processor.h
+++ b/tools/testing/selftests/kvm/include/riscv/processor.h
@@ -119,10 +119,12 @@ static inline void set_reg(struct kvm_vm *vm, uint32_t vcpuid, uint64_t id,
#define SATP_ASID_SHIFT 44
#define SATP_ASID_MASK _AC(0xFFFF, UL)
-#define SBI_EXT_EXPERIMENTAL_START 0x08000000
-#define SBI_EXT_EXPERIMENTAL_END 0x08FFFFFF
+#define SBI_EXT_EXPERIMENTAL_START 0x08000000
+#define SBI_EXT_EXPERIMENTAL_END 0x08FFFFFF
-#define KVM_RISCV_SELFTESTS_SBI_EXT SBI_EXT_EXPERIMENTAL_END
+#define KVM_RISCV_SELFTESTS_SBI_EXT SBI_EXT_EXPERIMENTAL_END
+#define KVM_RISCV_SELFTESTS_SBI_UCALL 0
+#define KVM_RISCV_SELFTESTS_SBI_UNEXP 1
struct sbiret {
long error;
diff --git a/tools/testing/selftests/kvm/lib/riscv/processor.c b/tools/testing/selftests/kvm/lib/riscv/processor.c
index 3961487a4870..56e4705f7744 100644
--- a/tools/testing/selftests/kvm/lib/riscv/processor.c
+++ b/tools/testing/selftests/kvm/lib/riscv/processor.c
@@ -268,10 +268,11 @@ void vcpu_dump(FILE *stream, struct kvm_vm *vm, uint32_t vcpuid, uint8_t indent)
core.regs.t3, core.regs.t4, core.regs.t5, core.regs.t6);
}
-static void __aligned(16) guest_hang(void)
+static void __aligned(16) guest_unexp_trap(void)
{
- while (1)
- ;
+ sbi_ecall(KVM_RISCV_SELFTESTS_SBI_EXT,
+ KVM_RISCV_SELFTESTS_SBI_UNEXP,
+ 0, 0, 0, 0, 0, 0);
}
void vm_vcpu_add_default(struct kvm_vm *vm, uint32_t vcpuid, void *guest_code)
@@ -310,7 +311,7 @@ void vm_vcpu_add_default(struct kvm_vm *vm, uint32_t vcpuid, void *guest_code)
/* Setup default exception vector of guest */
set_reg(vm, vcpuid, RISCV_CSR_REG(stvec),
- (unsigned long)guest_hang);
+ (unsigned long)guest_unexp_trap);
}
void vcpu_args_set(struct kvm_vm *vm, uint32_t vcpuid, unsigned int num, ...)
diff --git a/tools/testing/selftests/kvm/lib/riscv/ucall.c b/tools/testing/selftests/kvm/lib/riscv/ucall.c
index 9e42d8248fa6..8550f424d093 100644
--- a/tools/testing/selftests/kvm/lib/riscv/ucall.c
+++ b/tools/testing/selftests/kvm/lib/riscv/ucall.c
@@ -60,8 +60,9 @@ void ucall(uint64_t cmd, int nargs, ...)
uc.args[i] = va_arg(va, uint64_t);
va_end(va);
- sbi_ecall(KVM_RISCV_SELFTESTS_SBI_EXT, 0, (vm_vaddr_t)&uc,
- 0, 0, 0, 0, 0);
+ sbi_ecall(KVM_RISCV_SELFTESTS_SBI_EXT,
+ KVM_RISCV_SELFTESTS_SBI_UCALL,
+ (vm_vaddr_t)&uc, 0, 0, 0, 0, 0);
}
uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc)
@@ -73,14 +74,24 @@ uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc)
memset(uc, 0, sizeof(*uc));
if (run->exit_reason == KVM_EXIT_RISCV_SBI &&
- run->riscv_sbi.extension_id == KVM_RISCV_SELFTESTS_SBI_EXT &&
- run->riscv_sbi.function_id == 0) {
- memcpy(&ucall, addr_gva2hva(vm, run->riscv_sbi.args[0]),
- sizeof(ucall));
-
- vcpu_run_complete_io(vm, vcpu_id);
- if (uc)
- memcpy(uc, &ucall, sizeof(ucall));
+ run->riscv_sbi.extension_id == KVM_RISCV_SELFTESTS_SBI_EXT) {
+ switch (run->riscv_sbi.function_id) {
+ case KVM_RISCV_SELFTESTS_SBI_UCALL:
+ memcpy(&ucall, addr_gva2hva(vm,
+ run->riscv_sbi.args[0]), sizeof(ucall));
+
+ vcpu_run_complete_io(vm, vcpu_id);
+ if (uc)
+ memcpy(uc, &ucall, sizeof(ucall));
+
+ break;
+ case KVM_RISCV_SELFTESTS_SBI_UNEXP:
+ vcpu_dump(stderr, vm, vcpu_id, 2);
+ TEST_ASSERT(0, "Unexpected trap taken by guest");
+ break;
+ default:
+ break;
+ }
}
return ucall.cmd;
--
2.25.1
