Re: [PATCH] selftests/kvm: add set_boot_cpu_id test

On 17/03/21 08:44, Emanuele Giuseppe Esposito wrote:

• printf("vcpu executing...\n");
• vcpu_run(vm, vcpuid);
• printf("vcpu executed\n");
• switch (get_ucall(vm, vcpuid, &uc)) {
• case UCALL_SYNC:

• printf("stage %d sync %ld\n", stage, uc.args[1]);
  

• 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]);
  

• return;
  

• case UCALL_DONE:

• printf("got done\n");
  

You can remove the printfs here.

• return;
  

• 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 void add_x86_vcpu(struct kvm_vm *vm, uint32_t vcpuid, void *code) +{

• vm_vcpu_add_default(vm, vcpuid, code);
• vcpu_set_cpuid(vm, vcpuid, kvm_get_supported_cpuid());

+}

+static void run_vm_bsp(uint32_t bsp_vcpu) +{

• struct kvm_vm *vm;
• int stage;
• void *vcpu0_code, *vcpu1_code;
• vm = create_vm();
• vcpu0_code = guest_bsp_vcpu;
• vcpu1_code = guest_not_bsp_vcpu;
• if (bsp_vcpu == VCPU_ID1) {

• vcpu0_code = guest_not_bsp_vcpu;
  

• vcpu1_code = guest_bsp_vcpu;
  

• vm_ioctl(vm, KVM_SET_BOOT_CPU_ID, (void *) VCPU_ID1);
  

• }
• add_x86_vcpu(vm, VCPU_ID0, vcpu0_code);
• add_x86_vcpu(vm, VCPU_ID1, vcpu1_code);
• for (stage = 0; stage < 2; stage++) {

• run_vcpu(vm, VCPU_ID0, stage);
  

• run_vcpu(vm, VCPU_ID1, stage);
  

• }

These are just stylistic nits, but:

1) you could pass a bool to add_x86_vcpu, like

add_x86_vcpu(vm, VCPU_ID0, bsp_vcpu == VCPU_ID0); add_x86_vcpu(vm, VCPU_ID1, bsp_vcpu == VCPU_ID1);

instead of having the vcpu0_code and vcpu1_code pointers.

2) you could move the for loop inside run_vcpu. This way you can assert that you get UCALL_DONE when stage == 2.

• 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);

Looks good! Just another small change: since this third test is not adding much, you could instead invoke KVM_SET_BOOT_CPU_ID(VCPU_ID1) *after* the creation of the vCPUs instead of before. This should fail with -EBUSY, and vcpu 0 will remain the BSP.

Paolo