Commit f1c48c1e authored by Chao Du's avatar Chao Du Committed by Anup Patel
Browse files

RISC-V: KVM: selftests: Add ebreak test support 



Initial support for RISC-V KVM ebreak test. Check the exit reason and
the PC when guest debug is enabled. Also to make sure the guest could
handle the ebreak exception without exiting to the VMM when guest debug
is not enabled.

Signed-off-by: default avatarChao Du <duchao@eswincomputing.com>
Reviewed-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20240402062628.5425-4-duchao@eswincomputing.com


Signed-off-by: default avatarAnup Patel <anup@brainfault.org>
parent 1df1fb52

tools/testing/selftests/kvm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -189,6 +189,7 @@ 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/ebreak_test

TEST_GEN_PROGS_riscv += arch_timer

TEST_GEN_PROGS_riscv += demand_paging_test

TEST_GEN_PROGS_riscv += dirty_log_test

tools/testing/selftests/kvm/riscv/ebreak_test.c

0 → 100644
+82 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * RISC-V KVM ebreak test.

 *

 * Copyright 2024 Beijing ESWIN Computing Technology Co., Ltd.

 *

 */

#include "kvm_util.h"



#define LABEL_ADDRESS(v) ((uint64_t)&(v))



extern unsigned char sw_bp_1, sw_bp_2;

static uint64_t sw_bp_addr;



static void guest_code(void)

{

	asm volatile(

		".option push\n"

		".option norvc\n"

		"sw_bp_1: ebreak\n"

		"sw_bp_2: ebreak\n"

		".option pop\n"

	);

	GUEST_ASSERT_EQ(READ_ONCE(sw_bp_addr), LABEL_ADDRESS(sw_bp_2));



	GUEST_DONE();

}



static void guest_breakpoint_handler(struct ex_regs *regs)

{

	WRITE_ONCE(sw_bp_addr, regs->epc);

	regs->epc += 4;

}



int main(void)

{

	struct kvm_vm *vm;

	struct kvm_vcpu *vcpu;

	uint64_t pc;

	struct kvm_guest_debug debug = {

		.control = KVM_GUESTDBG_ENABLE,

	};



	TEST_REQUIRE(kvm_has_cap(KVM_CAP_SET_GUEST_DEBUG));



	vm = vm_create_with_one_vcpu(&vcpu, guest_code);



	vm_init_vector_tables(vm);

	vcpu_init_vector_tables(vcpu);

	vm_install_exception_handler(vm, EXC_BREAKPOINT,

					guest_breakpoint_handler);



	/*

	 * Enable the guest debug.

	 * ebreak should exit to the VMM with KVM_EXIT_DEBUG reason.

	 */

	vcpu_guest_debug_set(vcpu, &debug);

	vcpu_run(vcpu);



	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_DEBUG);



	vcpu_get_reg(vcpu, RISCV_CORE_REG(regs.pc), &pc);

	TEST_ASSERT_EQ(pc, LABEL_ADDRESS(sw_bp_1));



	/* skip sw_bp_1 */

	vcpu_set_reg(vcpu, RISCV_CORE_REG(regs.pc), pc + 4);



	/*

	 * Disable all debug controls.

	 * Guest should handle the ebreak without exiting to the VMM.

	 */

	memset(&debug, 0, sizeof(debug));

	vcpu_guest_debug_set(vcpu, &debug);



	vcpu_run(vcpu);



	TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_DONE);



	kvm_vm_free(vm);



	return 0;

}