Commit ac6c85e9 authored by Anup Patel's avatar Anup Patel Committed by Anup Patel
Browse files

KVM: selftests: riscv: Improve unexpected guest trap handling 



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: default avatarAnup Patel <apatel@ventanamicro.com>
Tested-by: default avatarMayuresh Chitale <mchitale@ventanamicro.com>
Signed-off-by: default avatarAnup Patel <anup@brainfault.org>
parent 42226c98

tools/testing/selftests/kvm/include/riscv/processor.h

+5 −3
Original line number Diff line number Diff line
@@ -123,6 +123,8 @@ static inline void set_reg(struct kvm_vm *vm, uint32_t vcpuid, uint64_t id, 
#define SBI_EXT_EXPERIMENTAL_END		0x08FFFFFF



#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;

tools/testing/selftests/kvm/lib/riscv/processor.c

+5 −4
Original line number Diff line number Diff line
@@ -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, ...)

tools/testing/selftests/kvm/lib/riscv/ucall.c

+21 −10
Original line number Diff line number Diff line
@@ -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));

	    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;