Commit cb97cf95 authored by Oliver Upton's avatar Oliver Upton Committed by Marc Zyngier
Browse files

selftests: KVM: Introduce psci_cpu_on_test 



Introduce a test for aarch64 that ensures CPU resets induced by PSCI are
reflected in the target vCPU's state, even if the target is never run
again. This is a regression test for a race between vCPU migration and
PSCI.

Reviewed-by: default avatarAndrew Jones <drjones@redhat.com>
Signed-off-by: default avatarOliver Upton <oupton@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210818202133.1106786-5-oupton@google.com
parent e10ecb4d

tools/testing/selftests/kvm/.gitignore

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# SPDX-License-Identifier: GPL-2.0-only

/aarch64/debug-exceptions

/aarch64/get-reg-list

/aarch64/psci_cpu_on_test

/aarch64/vgic_init

/s390x/memop

/s390x/resets

tools/testing/selftests/kvm/Makefile

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@@ -86,6 +86,7 @@ TEST_GEN_PROGS_x86_64 += kvm_binary_stats_test 


TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions

TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list

TEST_GEN_PROGS_aarch64 += aarch64/psci_cpu_on_test

TEST_GEN_PROGS_aarch64 += aarch64/vgic_init

TEST_GEN_PROGS_aarch64 += demand_paging_test

TEST_GEN_PROGS_aarch64 += dirty_log_test

tools/testing/selftests/kvm/aarch64/psci_cpu_on_test.c

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// SPDX-License-Identifier: GPL-2.0-only

/*

 * psci_cpu_on_test - Test that the observable state of a vCPU targeted by the

 * CPU_ON PSCI call matches what the caller requested.

 *

 * Copyright (c) 2021 Google LLC.

 *

 * This is a regression test for a race between KVM servicing the PSCI call and

 * userspace reading the vCPUs registers.

 */



#define _GNU_SOURCE



#include <linux/psci.h>



#include "kvm_util.h"

#include "processor.h"

#include "test_util.h"



#define VCPU_ID_SOURCE 0

#define VCPU_ID_TARGET 1



#define CPU_ON_ENTRY_ADDR 0xfeedf00dul

#define CPU_ON_CONTEXT_ID 0xdeadc0deul



static uint64_t psci_cpu_on(uint64_t target_cpu, uint64_t entry_addr,

			    uint64_t context_id)

{

	register uint64_t x0 asm("x0") = PSCI_0_2_FN64_CPU_ON;

	register uint64_t x1 asm("x1") = target_cpu;

	register uint64_t x2 asm("x2") = entry_addr;

	register uint64_t x3 asm("x3") = context_id;



	asm("hvc #0"

	    : "=r"(x0)

	    : "r"(x0), "r"(x1), "r"(x2), "r"(x3)

	    : "memory");



	return x0;

}



static uint64_t psci_affinity_info(uint64_t target_affinity,

				   uint64_t lowest_affinity_level)

{

	register uint64_t x0 asm("x0") = PSCI_0_2_FN64_AFFINITY_INFO;

	register uint64_t x1 asm("x1") = target_affinity;

	register uint64_t x2 asm("x2") = lowest_affinity_level;



	asm("hvc #0"

	    : "=r"(x0)

	    : "r"(x0), "r"(x1), "r"(x2)

	    : "memory");



	return x0;

}



static void guest_main(uint64_t target_cpu)

{

	GUEST_ASSERT(!psci_cpu_on(target_cpu, CPU_ON_ENTRY_ADDR, CPU_ON_CONTEXT_ID));

	uint64_t target_state;



	do {

		target_state = psci_affinity_info(target_cpu, 0);



		GUEST_ASSERT((target_state == PSCI_0_2_AFFINITY_LEVEL_ON) ||

			     (target_state == PSCI_0_2_AFFINITY_LEVEL_OFF));

	} while (target_state != PSCI_0_2_AFFINITY_LEVEL_ON);



	GUEST_DONE();

}



int main(void)

{

	uint64_t target_mpidr, obs_pc, obs_x0;

	struct kvm_vcpu_init init;

	struct kvm_vm *vm;

	struct ucall uc;



	vm = vm_create(VM_MODE_DEFAULT, DEFAULT_GUEST_PHY_PAGES, O_RDWR);

	kvm_vm_elf_load(vm, program_invocation_name);

	ucall_init(vm, NULL);



	vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init);

	init.features[0] |= (1 << KVM_ARM_VCPU_PSCI_0_2);



	aarch64_vcpu_add_default(vm, VCPU_ID_SOURCE, &init, guest_main);



	/*

	 * make sure the target is already off when executing the test.

	 */

	init.features[0] |= (1 << KVM_ARM_VCPU_POWER_OFF);

	aarch64_vcpu_add_default(vm, VCPU_ID_TARGET, &init, guest_main);



	get_reg(vm, VCPU_ID_TARGET, ARM64_SYS_REG(MPIDR_EL1), &target_mpidr);

	vcpu_args_set(vm, VCPU_ID_SOURCE, 1, target_mpidr & MPIDR_HWID_BITMASK);

	vcpu_run(vm, VCPU_ID_SOURCE);



	switch (get_ucall(vm, VCPU_ID_SOURCE, &uc)) {

	case UCALL_DONE:

		break;

	case UCALL_ABORT:

		TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0], __FILE__,

			  uc.args[1]);

		break;

	default:

		TEST_FAIL("Unhandled ucall: %lu", uc.cmd);

	}



	get_reg(vm, VCPU_ID_TARGET, ARM64_CORE_REG(regs.pc), &obs_pc);

	get_reg(vm, VCPU_ID_TARGET, ARM64_CORE_REG(regs.regs[0]), &obs_x0);



	TEST_ASSERT(obs_pc == CPU_ON_ENTRY_ADDR,

		    "unexpected target cpu pc: %lx (expected: %lx)",

		    obs_pc, CPU_ON_ENTRY_ADDR);

	TEST_ASSERT(obs_x0 == CPU_ON_CONTEXT_ID,

		    "unexpected target context id: %lx (expected: %lx)",

		    obs_x0, CPU_ON_CONTEXT_ID);



	kvm_vm_free(vm);

	return 0;

}

tools/testing/selftests/kvm/include/aarch64/processor.h

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Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#define CPACR_EL1               3, 0,  1, 0, 2

#define TCR_EL1                 3, 0,  2, 0, 2

#define MAIR_EL1                3, 0, 10, 2, 0

#define MPIDR_EL1               3, 0,  0, 0, 5

#define TTBR0_EL1               3, 0,  2, 0, 0

#define SCTLR_EL1               3, 0,  1, 0, 0

#define VBAR_EL1                3, 0, 12, 0, 0
@@ -40,6 +41,8 @@ 
			  (0xfful << (4 * 8)) | \

			  (0xbbul << (5 * 8)))



#define MPIDR_HWID_BITMASK (0xff00fffffful)



static inline void get_reg(struct kvm_vm *vm, uint32_t vcpuid, uint64_t id, uint64_t *addr)

{

	struct kvm_one_reg reg;