selftests: kvm: add set_boot_cpu_id test

Test for the KVM_SET_BOOT_CPU_ID ioctl.
Check that it correctly allows to change the BSP vcpu.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20210318151624.490861-2-eesposit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/.gitignore

@@ -14,6 +14,7 @@
 /x86_64/hyperv_cpuid
 /x86_64/mmio_warning_test
 /x86_64/platform_info_test
+/x86_64/set_boot_cpu_id
 /x86_64/set_sregs_test
 /x86_64/smm_test
 /x86_64/state_test

tools/testing/selftests/kvm/Makefile

@@ -47,6 +47,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/hyperv_cpuid
 TEST_GEN_PROGS_x86_64 += x86_64/kvm_pv_test
 TEST_GEN_PROGS_x86_64 += x86_64/mmio_warning_test
 TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test
+TEST_GEN_PROGS_x86_64 += x86_64/set_boot_cpu_id
 TEST_GEN_PROGS_x86_64 += x86_64/set_sregs_test
 TEST_GEN_PROGS_x86_64 += x86_64/smm_test
 TEST_GEN_PROGS_x86_64 += x86_64/state_test

tools/testing/selftests/kvm/x86_64/set_boot_cpu_id.c

@@ -0,0 +1,166 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test that KVM_SET_BOOT_CPU_ID works as intended
+ *
+ * Copyright (C) 2020, Red Hat, Inc.
+ */
+#define _GNU_SOURCE /* for program_invocation_name */
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+
+#define N_VCPU 2
+#define VCPU_ID0 0
+#define VCPU_ID1 1
+
+static uint32_t get_bsp_flag(void)
+{
+	return rdmsr(MSR_IA32_APICBASE) & MSR_IA32_APICBASE_BSP;
+}
+
+static void guest_bsp_vcpu(void *arg)
+{
+	GUEST_SYNC(1);
+
+	GUEST_ASSERT(get_bsp_flag() != 0);
+
+	GUEST_DONE();
+}
+
+static void guest_not_bsp_vcpu(void *arg)
+{
+	GUEST_SYNC(1);
+
+	GUEST_ASSERT(get_bsp_flag() == 0);
+
+	GUEST_DONE();
+}
+
+static void test_set_boot_busy(struct kvm_vm *vm)
+{
+	int res;
+
+	res = _vm_ioctl(vm, KVM_SET_BOOT_CPU_ID, (void *) VCPU_ID0);
+	TEST_ASSERT(res == -1 && errno == EBUSY,
+			"KVM_SET_BOOT_CPU_ID set while running vm");
+}
+
+static void run_vcpu(struct kvm_vm *vm, uint32_t vcpuid)
+{
+	struct ucall uc;
+	int stage;
+
+	for (stage = 0; stage < 2; stage++) {
+
+		vcpu_run(vm, vcpuid);
+
+		switch (get_ucall(vm, vcpuid, &uc)) {
+		case UCALL_SYNC:
+			TEST_ASSERT(!strcmp((const char *)uc.args[0], "hello") &&
+					uc.args[1] == stage + 1,
+					"Stage %d: Unexpected register values vmexit, got %lx",
+					stage + 1, (ulong)uc.args[1]);
+			test_set_boot_busy(vm);
+			break;
+		case UCALL_DONE:
+			TEST_ASSERT(stage == 1,
+					"Expected GUEST_DONE in stage 2, got stage %d",
+					stage);
+			break;
+		case UCALL_ABORT:
+			TEST_ASSERT(false, "%s at %s:%ld\n\tvalues: %#lx, %#lx",
+						(const char *)uc.args[0], __FILE__,
+						uc.args[1], uc.args[2], uc.args[3]);
+		default:
+			TEST_ASSERT(false, "Unexpected exit: %s",
+					exit_reason_str(vcpu_state(vm, vcpuid)->exit_reason));
+		}
+	}
+}
+
+static struct kvm_vm *create_vm(void)
+{
+	struct kvm_vm *vm;
+	uint64_t vcpu_pages = (DEFAULT_STACK_PGS) * 2;
+	uint64_t extra_pg_pages = vcpu_pages / PTES_PER_MIN_PAGE * N_VCPU;
+	uint64_t pages = DEFAULT_GUEST_PHY_PAGES + vcpu_pages + extra_pg_pages;
+
+	pages = vm_adjust_num_guest_pages(VM_MODE_DEFAULT, pages);
+	vm = vm_create(VM_MODE_DEFAULT, pages, O_RDWR);
+
+	kvm_vm_elf_load(vm, program_invocation_name, 0, 0);
+	vm_create_irqchip(vm);
+
+	return vm;
+}
+
+static void add_x86_vcpu(struct kvm_vm *vm, uint32_t vcpuid, bool bsp_code)
+{
+	if (bsp_code)
+		vm_vcpu_add_default(vm, vcpuid, guest_bsp_vcpu);
+	else
+		vm_vcpu_add_default(vm, vcpuid, guest_not_bsp_vcpu);
+
+	vcpu_set_cpuid(vm, vcpuid, kvm_get_supported_cpuid());
+}
+
+static void run_vm_bsp(uint32_t bsp_vcpu)
+{
+	struct kvm_vm *vm;
+	bool is_bsp_vcpu1 = bsp_vcpu == VCPU_ID1;
+
+	vm = create_vm();
+
+	if (is_bsp_vcpu1)
+		vm_ioctl(vm, KVM_SET_BOOT_CPU_ID, (void *) VCPU_ID1);
+
+	add_x86_vcpu(vm, VCPU_ID0, !is_bsp_vcpu1);
+	add_x86_vcpu(vm, VCPU_ID1, is_bsp_vcpu1);
+
+	run_vcpu(vm, VCPU_ID0);
+	run_vcpu(vm, VCPU_ID1);
+
+	kvm_vm_free(vm);
+}
+
+static void check_set_bsp_busy(void)
+{
+	struct kvm_vm *vm;
+	int res;
+
+	vm = create_vm();
+
+	add_x86_vcpu(vm, VCPU_ID0, true);
+	add_x86_vcpu(vm, VCPU_ID1, false);
+
+	res = _vm_ioctl(vm, KVM_SET_BOOT_CPU_ID, (void *) VCPU_ID1);
+	TEST_ASSERT(res == -1 && errno == EBUSY, "KVM_SET_BOOT_CPU_ID set after adding vcpu");
+
+	run_vcpu(vm, VCPU_ID0);
+	run_vcpu(vm, VCPU_ID1);
+
+	res = _vm_ioctl(vm, KVM_SET_BOOT_CPU_ID, (void *) VCPU_ID1);
+	TEST_ASSERT(res == -1 && errno == EBUSY, "KVM_SET_BOOT_CPU_ID set to a terminated vcpu");
+
+	kvm_vm_free(vm);
+}
+
+int main(int argc, char *argv[])
+{
+	if (!kvm_check_cap(KVM_CAP_SET_BOOT_CPU_ID)) {
+		print_skip("set_boot_cpu_id not available");
+		return 0;
+	}
+
+	run_vm_bsp(VCPU_ID0);
+	run_vm_bsp(VCPU_ID1);
+	run_vm_bsp(VCPU_ID0);
+
+	check_set_bsp_busy();
+}