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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * KVM_GET/SET_* tests
   4  *
   5  * Copyright (C) 2018, Red Hat, Inc.
   6  *
   7  * Tests for vCPU state save/restore, including nested guest state.
   8  */
   9 #define _GNU_SOURCE /* for program_invocation_short_name */
  10 #include <fcntl.h>
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14 #include <sys/ioctl.h>
  15
  16 #include "test_util.h"
  17
  18 #include "kvm_util.h"
  19 #include "processor.h"
  20 #include "vmx.h"
  21 #include "svm_util.h"
  22
  23 #define L2_GUEST_STACK_SIZE 256
  24
  25 void svm_l2_guest_code(void)
  26 {
  27         GUEST_SYNC(4);
  28         /* Exit to L1 */
  29         vmcall();
  30         GUEST_SYNC(6);
  31         /* Done, exit to L1 and never come back.  */
  32         vmcall();
  33 }
  34
  35 static void svm_l1_guest_code(struct svm_test_data *svm)
  36 {
  37         unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
  38         struct vmcb *vmcb = svm->vmcb;
  39
  40         GUEST_ASSERT(svm->vmcb_gpa);
  41         /* Prepare for L2 execution. */
  42         generic_svm_setup(svm, svm_l2_guest_code,
  43                           &l2_guest_stack[L2_GUEST_STACK_SIZE]);
  44
  45         GUEST_SYNC(3);
  46         run_guest(vmcb, svm->vmcb_gpa);
  47         GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
  48         GUEST_SYNC(5);
  49         vmcb->save.rip += 3;
  50         run_guest(vmcb, svm->vmcb_gpa);
  51         GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
  52         GUEST_SYNC(7);
  53 }
  54
  55 void vmx_l2_guest_code(void)
  56 {
  57         GUEST_SYNC(6);
  58
  59         /* Exit to L1 */
  60         vmcall();
  61
  62         /* L1 has now set up a shadow VMCS for us.  */
  63         GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);
  64         GUEST_SYNC(10);
  65         GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);
  66         GUEST_ASSERT(!vmwrite(GUEST_RIP, 0xc0fffee));
  67         GUEST_SYNC(11);
  68         GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0fffee);
  69         GUEST_ASSERT(!vmwrite(GUEST_RIP, 0xc0ffffee));
  70         GUEST_SYNC(12);
  71
  72         /* Done, exit to L1 and never come back.  */
  73         vmcall();
  74 }
  75
  76 static void vmx_l1_guest_code(struct vmx_pages *vmx_pages)
  77 {
  78         unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
  79
  80         GUEST_ASSERT(vmx_pages->vmcs_gpa);
  81         GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
  82         GUEST_SYNC(3);
  83         GUEST_ASSERT(load_vmcs(vmx_pages));
  84         GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
  85
  86         GUEST_SYNC(4);
  87         GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
  88
  89         prepare_vmcs(vmx_pages, vmx_l2_guest_code,
  90                      &l2_guest_stack[L2_GUEST_STACK_SIZE]);
  91
  92         GUEST_SYNC(5);
  93         GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
  94         GUEST_ASSERT(!vmlaunch());
  95         GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
  96         GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
  97
  98         /* Check that the launched state is preserved.  */
  99         GUEST_ASSERT(vmlaunch());
 100
 101         GUEST_ASSERT(!vmresume());
 102         GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
 103
 104         GUEST_SYNC(7);
 105         GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
 106
 107         GUEST_ASSERT(!vmresume());
 108         GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
 109
 110         vmwrite(GUEST_RIP, vmreadz(GUEST_RIP) + 3);
 111
 112         vmwrite(SECONDARY_VM_EXEC_CONTROL, SECONDARY_EXEC_SHADOW_VMCS);
 113         vmwrite(VMCS_LINK_POINTER, vmx_pages->shadow_vmcs_gpa);
 114
 115         GUEST_ASSERT(!vmptrld(vmx_pages->shadow_vmcs_gpa));
 116         GUEST_ASSERT(vmlaunch());
 117         GUEST_SYNC(8);
 118         GUEST_ASSERT(vmlaunch());
 119         GUEST_ASSERT(vmresume());
 120
 121         vmwrite(GUEST_RIP, 0xc0ffee);
 122         GUEST_SYNC(9);
 123         GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);
 124
 125         GUEST_ASSERT(!vmptrld(vmx_pages->vmcs_gpa));
 126         GUEST_ASSERT(!vmresume());
 127         GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
 128
 129         GUEST_ASSERT(!vmptrld(vmx_pages->shadow_vmcs_gpa));
 130         GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffffee);
 131         GUEST_ASSERT(vmlaunch());
 132         GUEST_ASSERT(vmresume());
 133         GUEST_SYNC(13);
 134         GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffffee);
 135         GUEST_ASSERT(vmlaunch());
 136         GUEST_ASSERT(vmresume());
 137 }
 138
 139 static void __attribute__((__flatten__)) guest_code(void *arg)
 140 {
 141         GUEST_SYNC(1);
 142
 143         if (this_cpu_has(X86_FEATURE_XSAVE)) {
 144                 uint64_t supported_xcr0 = this_cpu_supported_xcr0();
 145                 uint8_t buffer[4096];
 146
 147                 memset(buffer, 0xcc, sizeof(buffer));
 148
 149                 set_cr4(get_cr4() | X86_CR4_OSXSAVE);
 150                 GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSXSAVE));
 151
 152                 xsetbv(0, xgetbv(0) | supported_xcr0);
 153
 154                 /*
 155                  * Modify state for all supported xfeatures to take them out of
 156                  * their "init" state, i.e. to make them show up in XSTATE_BV.
 157                  *
 158                  * Note off-by-default features, e.g. AMX, are out of scope for
 159                  * this particular testcase as they have a different ABI.
 160                  */
 161                 GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_FP);
 162                 asm volatile ("fincstp");
 163
 164                 GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_SSE);
 165                 asm volatile ("vmovdqu %0, %%xmm0" :: "m" (buffer));
 166
 167                 if (supported_xcr0 & XFEATURE_MASK_YMM)
 168                         asm volatile ("vmovdqu %0, %%ymm0" :: "m" (buffer));
 169
 170                 if (supported_xcr0 & XFEATURE_MASK_AVX512) {
 171                         asm volatile ("kmovq %0, %%k1" :: "r" (-1ull));
 172                         asm volatile ("vmovupd %0, %%zmm0" :: "m" (buffer));
 173                         asm volatile ("vmovupd %0, %%zmm16" :: "m" (buffer));
 174                 }
 175
 176                 if (this_cpu_has(X86_FEATURE_MPX)) {
 177                         uint64_t bounds[2] = { 10, 0xffffffffull };
 178                         uint64_t output[2] = { };
 179
 180                         GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_BNDREGS);
 181                         GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_BNDCSR);
 182
 183                         /*
 184                          * Don't bother trying to get BNDCSR into the INUSE
 185                          * state.  MSR_IA32_BNDCFGS doesn't count as it isn't
 186                          * managed via XSAVE/XRSTOR, and BNDCFGU can only be
 187                          * modified by XRSTOR.  Stuffing XSTATE_BV in the host
 188                          * is simpler than doing XRSTOR here in the guest.
 189                          *
 190                          * However, temporarily enable MPX in BNDCFGS so that
 191                          * BNDMOV actually loads BND1.  If MPX isn't *fully*
 192                          * enabled, all MPX instructions are treated as NOPs.
 193                          *
 194                          * Hand encode "bndmov (%rax),%bnd1" as support for MPX
 195                          * mnemonics/registers has been removed from gcc and
 196                          * clang (and was never fully supported by clang).
 197                          */
 198                         wrmsr(MSR_IA32_BNDCFGS, BIT_ULL(0));
 199                         asm volatile (".byte 0x66,0x0f,0x1a,0x08" :: "a" (bounds));
 200                         /*
 201                          * Hand encode "bndmov %bnd1, (%rax)" to sanity check
 202                          * that BND1 actually got loaded.
 203                          */
 204                         asm volatile (".byte 0x66,0x0f,0x1b,0x08" :: "a" (output));
 205                         wrmsr(MSR_IA32_BNDCFGS, 0);
 206
 207                         GUEST_ASSERT_EQ(bounds[0], output[0]);
 208                         GUEST_ASSERT_EQ(bounds[1], output[1]);
 209                 }
 210                 if (this_cpu_has(X86_FEATURE_PKU)) {
 211                         GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_PKRU);
 212                         set_cr4(get_cr4() | X86_CR4_PKE);
 213                         GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSPKE));
 214
 215                         wrpkru(-1u);
 216                 }
 217         }
 218
 219         GUEST_SYNC(2);
 220
 221         if (arg) {
 222                 if (this_cpu_has(X86_FEATURE_SVM))
 223                         svm_l1_guest_code(arg);
 224                 else
 225                         vmx_l1_guest_code(arg);
 226         }
 227
 228         GUEST_DONE();
 229 }
 230
 231 int main(int argc, char *argv[])
 232 {
 233         uint64_t *xstate_bv, saved_xstate_bv;
 234         vm_vaddr_t nested_gva = 0;
 235         struct kvm_cpuid2 empty_cpuid = {};
 236         struct kvm_regs regs1, regs2;
 237         struct kvm_vcpu *vcpu, *vcpuN;
 238         struct kvm_vm *vm;
 239         struct kvm_x86_state *state;
 240         struct ucall uc;
 241         int stage;
 242
 243         /* Create VM */
 244         vm = vm_create_with_one_vcpu(&vcpu, guest_code);
 245
 246         vcpu_regs_get(vcpu, &regs1);
 247
 248         if (kvm_has_cap(KVM_CAP_NESTED_STATE)) {
 249                 if (kvm_cpu_has(X86_FEATURE_SVM))
 250                         vcpu_alloc_svm(vm, &nested_gva);
 251                 else if (kvm_cpu_has(X86_FEATURE_VMX))
 252                         vcpu_alloc_vmx(vm, &nested_gva);
 253         }
 254
 255         if (!nested_gva)
 256                 pr_info("will skip nested state checks\n");
 257
 258         vcpu_args_set(vcpu, 1, nested_gva);
 259
 260         for (stage = 1;; stage++) {
 261                 vcpu_run(vcpu);
 262                 TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
 263
 264                 switch (get_ucall(vcpu, &uc)) {
 265                 case UCALL_ABORT:
 266                         REPORT_GUEST_ASSERT(uc);
 267                         /* NOT REACHED */
 268                 case UCALL_SYNC:
 269                         break;
 270                 case UCALL_DONE:
 271                         goto done;
 272                 default:
 273                         TEST_FAIL("Unknown ucall %lu", uc.cmd);
 274                 }
 275
 276                 /* UCALL_SYNC is handled here.  */
 277                 TEST_ASSERT(!strcmp((const char *)uc.args[0], "hello") &&
 278                             uc.args[1] == stage, "Stage %d: Unexpected register values vmexit, got %lx",
 279                             stage, (ulong)uc.args[1]);
 280
 281                 state = vcpu_save_state(vcpu);
 282                 memset(&regs1, 0, sizeof(regs1));
 283                 vcpu_regs_get(vcpu, &regs1);
 284
 285                 kvm_vm_release(vm);
 286
 287                 /* Restore state in a new VM.  */
 288                 vcpu = vm_recreate_with_one_vcpu(vm);
 289                 vcpu_load_state(vcpu, state);
 290
 291                 /*
 292                  * Restore XSAVE state in a dummy vCPU, first without doing
 293                  * KVM_SET_CPUID2, and then with an empty guest CPUID.  Except
 294                  * for off-by-default xfeatures, e.g. AMX, KVM is supposed to
 295                  * allow KVM_SET_XSAVE regardless of guest CPUID.  Manually
 296                  * load only XSAVE state, MSRs in particular have a much more
 297                  * convoluted ABI.
 298                  *
 299                  * Load two versions of XSAVE state: one with the actual guest
 300                  * XSAVE state, and one with all supported features forced "on"
 301                  * in xstate_bv, e.g. to ensure that KVM allows loading all
 302                  * supported features, even if something goes awry in saving
 303                  * the original snapshot.
 304                  */
 305                 xstate_bv = (void *)&((uint8_t *)state->xsave->region)[512];
 306                 saved_xstate_bv = *xstate_bv;
 307
 308                 vcpuN = __vm_vcpu_add(vm, vcpu->id + 1);
 309                 vcpu_xsave_set(vcpuN, state->xsave);
 310                 *xstate_bv = kvm_cpu_supported_xcr0();
 311                 vcpu_xsave_set(vcpuN, state->xsave);
 312
 313                 vcpu_init_cpuid(vcpuN, &empty_cpuid);
 314                 vcpu_xsave_set(vcpuN, state->xsave);
 315                 *xstate_bv = saved_xstate_bv;
 316                 vcpu_xsave_set(vcpuN, state->xsave);
 317
 318                 kvm_x86_state_cleanup(state);
 319
 320                 memset(&regs2, 0, sizeof(regs2));
 321                 vcpu_regs_get(vcpu, &regs2);
 322                 TEST_ASSERT(!memcmp(&regs1, &regs2, sizeof(regs2)),
 323                             "Unexpected register values after vcpu_load_state; rdi: %lx rsi: %lx",
 324                             (ulong) regs2.rdi, (ulong) regs2.rsi);
 325         }
 326
 327 done:
 328         kvm_vm_free(vm);
 329 }