1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * vmx_apic_access_test 4 * 5 * Copyright (C) 2020, Google LLC. 6 * 7 * This work is licensed under the terms of the GNU GPL, version 2. 8 * 9 * The first subtest simply checks to see that an L2 guest can be 10 * launched with a valid APIC-access address that is backed by a 11 * page of L1 physical memory. 12 * 13 * The second subtest sets the APIC-access address to a (valid) L1 14 * physical address that is not backed by memory. KVM can't handle 15 * this situation, so resuming L2 should result in a KVM exit for 16 * internal error (emulation). This is not an architectural 17 * requirement. It is just a shortcoming of KVM. The internal error 18 * is unfortunate, but it's better than what used to happen! 19 */ 20 21 #include "test_util.h" 22 #include "kvm_util.h" 23 #include "processor.h" 24 #include "vmx.h" 25 26 #include <string.h> 27 #include <sys/ioctl.h> 28 29 #include "kselftest.h" 30 31 #define VCPU_ID 0 32 33 /* The virtual machine object. */ 34 static struct kvm_vm *vm; 35 36 static void l2_guest_code(void) 37 { 38 /* Exit to L1 */ 39 __asm__ __volatile__("vmcall"); 40 } 41 42 static void l1_guest_code(struct vmx_pages *vmx_pages, unsigned long high_gpa) 43 { 44 #define L2_GUEST_STACK_SIZE 64 45 unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE]; 46 uint32_t control; 47 48 GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages)); 49 GUEST_ASSERT(load_vmcs(vmx_pages)); 50 51 /* Prepare the VMCS for L2 execution. */ 52 prepare_vmcs(vmx_pages, l2_guest_code, 53 &l2_guest_stack[L2_GUEST_STACK_SIZE]); 54 control = vmreadz(CPU_BASED_VM_EXEC_CONTROL); 55 control |= CPU_BASED_ACTIVATE_SECONDARY_CONTROLS; 56 vmwrite(CPU_BASED_VM_EXEC_CONTROL, control); 57 control = vmreadz(SECONDARY_VM_EXEC_CONTROL); 58 control |= SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES; 59 vmwrite(SECONDARY_VM_EXEC_CONTROL, control); 60 vmwrite(APIC_ACCESS_ADDR, vmx_pages->apic_access_gpa); 61 62 /* Try to launch L2 with the memory-backed APIC-access address. */ 63 GUEST_SYNC(vmreadz(APIC_ACCESS_ADDR)); 64 GUEST_ASSERT(!vmlaunch()); 65 GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL); 66 67 vmwrite(APIC_ACCESS_ADDR, high_gpa); 68 69 /* Try to resume L2 with the unbacked APIC-access address. */ 70 GUEST_SYNC(vmreadz(APIC_ACCESS_ADDR)); 71 GUEST_ASSERT(!vmresume()); 72 GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL); 73 74 GUEST_DONE(); 75 } 76 77 int main(int argc, char *argv[]) 78 { 79 unsigned long apic_access_addr = ~0ul; 80 unsigned int paddr_width; 81 unsigned int vaddr_width; 82 vm_vaddr_t vmx_pages_gva; 83 unsigned long high_gpa; 84 struct vmx_pages *vmx; 85 bool done = false; 86 87 nested_vmx_check_supported(); 88 89 vm = vm_create_default(VCPU_ID, 0, (void *) l1_guest_code); 90 91 kvm_get_cpu_address_width(&paddr_width, &vaddr_width); 92 high_gpa = (1ul << paddr_width) - getpagesize(); 93 if ((unsigned long)DEFAULT_GUEST_PHY_PAGES * getpagesize() > high_gpa) { 94 print_skip("No unbacked physical page available"); 95 exit(KSFT_SKIP); 96 } 97 98 vmx = vcpu_alloc_vmx(vm, &vmx_pages_gva); 99 prepare_virtualize_apic_accesses(vmx, vm); 100 vcpu_args_set(vm, VCPU_ID, 2, vmx_pages_gva, high_gpa); 101 102 while (!done) { 103 volatile struct kvm_run *run = vcpu_state(vm, VCPU_ID); 104 struct ucall uc; 105 106 vcpu_run(vm, VCPU_ID); 107 if (apic_access_addr == high_gpa) { 108 TEST_ASSERT(run->exit_reason == 109 KVM_EXIT_INTERNAL_ERROR, 110 "Got exit reason other than KVM_EXIT_INTERNAL_ERROR: %u (%s)\n", 111 run->exit_reason, 112 exit_reason_str(run->exit_reason)); 113 TEST_ASSERT(run->internal.suberror == 114 KVM_INTERNAL_ERROR_EMULATION, 115 "Got internal suberror other than KVM_INTERNAL_ERROR_EMULATION: %u\n", 116 run->internal.suberror); 117 break; 118 } 119 TEST_ASSERT(run->exit_reason == KVM_EXIT_IO, 120 "Got exit_reason other than KVM_EXIT_IO: %u (%s)\n", 121 run->exit_reason, 122 exit_reason_str(run->exit_reason)); 123 124 switch (get_ucall(vm, VCPU_ID, &uc)) { 125 case UCALL_ABORT: 126 TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0], 127 __FILE__, uc.args[1]); 128 /* NOT REACHED */ 129 case UCALL_SYNC: 130 apic_access_addr = uc.args[1]; 131 break; 132 case UCALL_DONE: 133 done = true; 134 break; 135 default: 136 TEST_ASSERT(false, "Unknown ucall %lu", uc.cmd); 137 } 138 } 139 kvm_vm_free(vm); 140 return 0; 141 } 142