| // Copyright 2017 syzkaller project authors. All rights reserved. |
| // Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file. |
| |
| #include <error.h> |
| #include <stdint.h> |
| #include <sys/utsname.h> |
| |
| static unsigned host_kernel_version(); |
| static void dump_cpu_state(int cpufd, char* vm_mem); |
| |
| #ifdef GOARCH_amd64 |
| static int cpu_feature_enabled(uint32_t function, uint32_t eax_bits, uint32_t ebx_bits, uint32_t ecx_bits, uint32_t edx_bits); |
| |
| #define FEATURE_INTEL 0x00000001 |
| #define FEATURE_INTEL_ECX_VMX (1 << 5) |
| |
| #define FEATURE_AMD 0x800000001 |
| #define FEATURE_AMD_ECX_SVM (1 << 2) |
| #endif |
| |
| static int test_one(int text_type, const char* text, int text_size, int flags, unsigned reason, bool check_rax) |
| { |
| printf("=== testing text %d, text size 0x%x, flags 0x%x\n", text_type, text_size, flags); |
| int kvmfd = open("/dev/kvm", O_RDWR); |
| if (kvmfd == -1) { |
| if (errno == ENOENT) { |
| printf("/dev/kvm is not present\n"); |
| return -1; |
| } |
| if (errno == EPERM || errno == EACCES) { |
| printf("no permissions to open /dev/kvm\n"); |
| return -1; |
| } |
| printf("failed to open /dev/kvm (%d)\n", errno); |
| return 1; |
| } |
| int vmfd = ioctl(kvmfd, KVM_CREATE_VM, 0); |
| if (vmfd == -1) { |
| printf("KVM_CREATE_VM failed (%d)\n", errno); |
| return 1; |
| } |
| int cpufd = ioctl(vmfd, KVM_CREATE_VCPU, 0); |
| if (cpufd == -1) { |
| printf("KVM_CREATE_VCPU failed (%d)\n", errno); |
| return 1; |
| } |
| int cpu_mem_size = ioctl(kvmfd, KVM_GET_VCPU_MMAP_SIZE, 0); |
| if (cpu_mem_size <= 0) { |
| printf("KVM_GET_VCPU_MMAP_SIZE failed (%d)\n", errno); |
| return 1; |
| } |
| struct kvm_run* cpu_mem = (struct kvm_run*)mmap(0, cpu_mem_size, |
| PROT_READ | PROT_WRITE, MAP_SHARED, cpufd, 0); |
| if (cpu_mem == MAP_FAILED) { |
| printf("cpu mmap failed (%d)\n", errno); |
| return 1; |
| } |
| int vm_mem_size = 24 * SYZ_PAGE_SIZE; // Allocate what executor allocates for vma[24] |
| void* vm_mem = mmap(0, vm_mem_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
| if (vm_mem == MAP_FAILED) { |
| printf("mmap failed (%d)\n", errno); |
| return 1; |
| } |
| struct kvm_text kvm_text; |
| kvm_text.typ = text_type; |
| kvm_text.text = text; |
| kvm_text.size = text_size; |
| if (syz_kvm_setup_cpu(vmfd, cpufd, (uintptr_t)vm_mem, (uintptr_t)&kvm_text, 1, flags, 0, 0)) { |
| printf("syz_kvm_setup_cpu failed (%d)\n", errno); |
| return 1; |
| } |
| |
| int ret = ioctl(cpufd, KVM_RUN, 0); |
| // KVM_RUN returns positive values on PPC64 |
| if (ret < 0) { |
| printf("KVM_RUN returned %d, errno=%d\n", ret, errno); |
| return 1; |
| } |
| struct kvm_regs regs; |
| if (ioctl(cpufd, KVM_GET_REGS, ®s)) { |
| printf("KVM_GET_REGS failed (%d)\n", errno); |
| dump_cpu_state(cpufd, (char*)vm_mem); |
| return 1; |
| } |
| if (cpu_mem->exit_reason != reason) { |
| printf("KVM_RUN exit reason %d, expect %d\n", cpu_mem->exit_reason, reason); |
| if (cpu_mem->exit_reason == KVM_EXIT_FAIL_ENTRY) |
| printf("hardware exit reason 0x%llx\n", |
| (unsigned long long)cpu_mem->fail_entry.hardware_entry_failure_reason); |
| dump_cpu_state(cpufd, (char*)vm_mem); |
| return 1; |
| } |
| #ifdef GOARCH_amd64 |
| if (check_rax && regs.rax != 0xbadc0de) { |
| printf("wrong result: rax=0x%llx\n", (long long)regs.rax); |
| dump_cpu_state(cpufd, (char*)vm_mem); |
| return 1; |
| } |
| #elif GOARCH_ppc64le |
| if (check_rax && regs.gpr[3] != 0xbadc0de) { |
| printf("wrong result: gps[3]=0x%llx\n", (long long)regs.gpr[3]); |
| dump_cpu_state(cpufd, (char*)vm_mem); |
| return 1; |
| } |
| #endif |
| munmap(vm_mem, vm_mem_size); |
| munmap(cpu_mem, cpu_mem_size); |
| close(cpufd); |
| close(vmfd); |
| close(kvmfd); |
| return 0; |
| } |
| |
| static int test_kvm() |
| { |
| int res = 0; |
| |
| unsigned ver = host_kernel_version(); |
| printf("host kernel version %u\n", ver); |
| |
| // TODO: test VM mode. |
| // const char text16_vm[] = "\x48\xc7\xc3\xde\xc0\xad\x0b\x90\x90\x48\xc7\xc0\xef\xcd\xab\x00\xf4"; |
| // if (res = test_one(64, text16_vm, sizeof(text16_vm) - 1, KVM_SETUP_VM, KVM_EXIT_HLT, true)) |
| // return res; |
| |
| // TODO: test code executed in interrupt handlers. |
| // const char text32_div0[] = "\x31\xc0\xf7\xf0"; |
| // if (res = test_one(32, text32_div0, sizeof(text32_div0)-1, 0, KVM_EXIT_HLT, true)) |
| // return res; |
| |
| #ifdef GOARCH_amd64 |
| // Note: VIRT86 and CPL3 prefix seems to work with vmx only |
| if (cpu_feature_enabled(FEATURE_INTEL, 0, 0, FEATURE_INTEL_ECX_VMX, 0) == 1) { |
| const char text8[] = "\x66\xb8\xde\xc0\xad\x0b"; |
| if ((res = test_one(8, text8, sizeof(text8) - 1, 0, KVM_EXIT_HLT, true))) |
| return res; |
| if ((res = test_one(8, text8, sizeof(text8) - 1, KVM_SETUP_VIRT86, KVM_EXIT_SHUTDOWN, true))) |
| return res; |
| if ((res = test_one(8, text8, sizeof(text8) - 1, KVM_SETUP_VIRT86 | KVM_SETUP_PAGING, KVM_EXIT_SHUTDOWN, true))) |
| return res; |
| |
| const char text16[] = "\x66\xb8\xde\xc0\xad\x0b"; |
| if ((res = test_one(16, text16, sizeof(text16) - 1, 0, KVM_EXIT_HLT, true))) |
| return res; |
| if ((res = test_one(16, text16, sizeof(text16) - 1, KVM_SETUP_CPL3, KVM_EXIT_SHUTDOWN, true))) |
| return res; |
| |
| const char text32[] = "\xb8\xde\xc0\xad\x0b"; |
| if ((res = test_one(32, text32, sizeof(text32) - 1, 0, KVM_EXIT_HLT, true))) |
| return res; |
| if ((res = test_one(32, text32, sizeof(text32) - 1, KVM_SETUP_PAGING, KVM_EXIT_HLT, true))) |
| return res; |
| if ((res = test_one(32, text32, sizeof(text32) - 1, KVM_SETUP_CPL3, KVM_EXIT_SHUTDOWN, true))) |
| return res; |
| |
| const char text64[] = "\x90\xb8\xde\xc0\xad\x0b"; |
| if ((res = test_one(64, text64, sizeof(text64) - 1, 0, KVM_EXIT_HLT, true))) |
| return res; |
| if ((res = test_one(64, text64, sizeof(text64) - 1, KVM_SETUP_PAGING, KVM_EXIT_HLT, true))) |
| return res; |
| if ((res = test_one(64, text64, sizeof(text64) - 1, KVM_SETUP_CPL3, KVM_EXIT_SHUTDOWN, true))) |
| return res; |
| |
| const char text64_sysenter[] = "\xb8\xde\xc0\xad\x0b\x0f\x34"; |
| if ((res = test_one(64, text64_sysenter, sizeof(text64_sysenter) - 1, KVM_SETUP_CPL3, KVM_EXIT_SHUTDOWN, true))) |
| return res; |
| } |
| |
| // Note: SMM does not work on 3.13 kernels. |
| if (ver >= 404) { |
| const char text8_smm[] = "\x66\xb8\xde\xc0\xad\x0b"; |
| if ((res = test_one(8, text8_smm, sizeof(text8_smm) - 1, KVM_SETUP_SMM, KVM_EXIT_HLT, true))) |
| return res; |
| if ((res = test_one(8, text8_smm, sizeof(text8_smm) - 1, KVM_SETUP_SMM | KVM_SETUP_PROTECTED, KVM_EXIT_HLT, true))) |
| return res; |
| |
| // const char text32_smm[] = "\xb8\xde\xc0\xad\x0b"; |
| if ((res = test_one(32, text8_smm, sizeof(text8_smm) - 1, KVM_SETUP_SMM, KVM_EXIT_HLT, true))) |
| return res; |
| |
| // Also ensure that we are actually in SMM. |
| // If we do MOV to RAX and then RSM, RAX will be restored to host value so RAX check will fail. |
| // So instead we execute just RSM, if we are in SMM we will get KVM_EXIT_HLT, |
| // otherwise KVM_EXIT_INTERNAL_ERROR. |
| const char text_rsm[] = "\x0f\xaa"; |
| if ((res = test_one(8, text_rsm, sizeof(text_rsm) - 1, KVM_SETUP_SMM, KVM_EXIT_HLT, false))) |
| return res; |
| if ((res = test_one(32, text_rsm, sizeof(text_rsm) - 1, KVM_SETUP_SMM, KVM_EXIT_HLT, false))) |
| return res; |
| } |
| #elif GOARCH_ppc64le |
| for (unsigned i = 0; i < (1 << 5); ++i) { |
| res = test_one(8, kvm_ppc64_mr, sizeof(kvm_ppc64_mr) - 1, i, KVM_EXIT_DEBUG, true); |
| if (res) |
| return res; |
| res = test_one(8, kvm_ppc64_ld, sizeof(kvm_ppc64_ld) - 1, i, KVM_EXIT_DEBUG, true); |
| if (res) |
| return res; |
| } |
| #else |
| // Keeping gcc happy |
| const char text8[] = "\x66\xb8\xde\xc0\xad\x0b"; |
| if ((res = test_one(8, text8, sizeof(text8) - 1, 0, KVM_EXIT_HLT, true))) |
| return res; |
| #endif |
| |
| return 0; |
| } |
| |
| static unsigned host_kernel_version() |
| { |
| struct utsname name; |
| if (uname(&name)) { |
| printf("uname failed (%d)\n", errno); |
| doexit(1); |
| } |
| unsigned major = atoi(name.release); |
| unsigned minor = 0; |
| if (strchr(name.release, '.')) |
| minor = atoi(strchr(name.release, '.') + 1); |
| return major * 100 + minor; |
| } |
| |
| #ifdef GOARCH_amd64 |
| static void dump_seg(const char* name, struct kvm_segment* seg) |
| { |
| printf("%s: base=0x%llx limit=0x%x sel=0x%x type=%d p=%d dpl=%d, db=%d s=%d l=%d g=%d\n", |
| name, seg->base, seg->limit, seg->selector, seg->type, seg->present, seg->dpl, seg->db, seg->s, seg->l, seg->g); |
| } |
| #endif |
| |
| static void dump_cpu_state(int cpufd, char* vm_mem) |
| { |
| struct kvm_sregs sregs; |
| if (ioctl(cpufd, KVM_GET_SREGS, &sregs)) { |
| printf("KVM_GET_SREGS failed (%d)\n", errno); |
| return; |
| } |
| struct kvm_regs regs; |
| if (ioctl(cpufd, KVM_GET_REGS, ®s)) { |
| printf("KVM_GET_REGS failed (%d)\n", errno); |
| return; |
| } |
| #ifdef GOARCH_amd64 |
| printf("RIP=0x%llx RAX=0x%llx RDX=0x%llx RCX=0x%llx RBX=0x%llx CF=%d ZF=%d\n", |
| regs.rip, regs.rax, regs.rdx, regs.rcx, regs.rbx, !!(regs.rflags & (1 << 0)), !!(regs.rflags & (1 << 6))); |
| printf("CR0=0x%llx CR2=0x%llx CR4=0x%llx EFER=0x%llx\n", |
| sregs.cr0, sregs.cr2, sregs.cr4, sregs.efer); |
| dump_seg("CS", &sregs.cs); |
| dump_seg("SS", &sregs.ss); |
| dump_seg("DS", &sregs.ds); |
| |
| if (false) { |
| printf("memory:\n"); |
| for (int i = 0; i < 0x80; i++) |
| printf("0x%02x: 0x%02x\n", i, ((unsigned char*)vm_mem)[i]); |
| } |
| |
| if (false) { |
| printf("vmcs:\n"); |
| const int vmcs_size = 0x1000; |
| for (int i = 0; i < vmcs_size / 8; i += 4) { |
| printf("0x%04x: 0x%016llx 0x%016llx 0x%016llx 0x%016llx\n", i, |
| ((long long*)vm_mem)[i], ((long long*)vm_mem)[i + 1], ((long long*)vm_mem)[i + 2], ((long long*)vm_mem)[i + 3]); |
| } |
| } |
| #elif GOARCH_ppc64 || GOARCH_ppc64le |
| printf("NIP %016lx\n", regs.pc); |
| printf("MSR %016lx\n", regs.msr); |
| printf("GPR00 %016lx %016lx %016lx %016lx\n", regs.gpr[0], regs.gpr[1], regs.gpr[2], regs.gpr[3]); |
| printf("GPR04 %016lx %016lx %016lx %016lx\n", regs.gpr[4], regs.gpr[5], regs.gpr[6], regs.gpr[7]); |
| printf("GPR08 %016lx %016lx %016lx %016lx\n", regs.gpr[8], regs.gpr[9], regs.gpr[10], regs.gpr[11]); |
| printf("GPR12 %016lx %016lx %016lx %016lx\n", regs.gpr[12], regs.gpr[13], regs.gpr[14], regs.gpr[15]); |
| printf("GPR16 %016lx %016lx %016lx %016lx\n", regs.gpr[16], regs.gpr[17], regs.gpr[18], regs.gpr[19]); |
| printf("GPR20 %016lx %016lx %016lx %016lx\n", regs.gpr[20], regs.gpr[21], regs.gpr[22], regs.gpr[23]); |
| printf("GPR24 %016lx %016lx %016lx %016lx\n", regs.gpr[24], regs.gpr[25], regs.gpr[26], regs.gpr[27]); |
| printf("GPR28 %016lx %016lx %016lx %016lx\n", regs.gpr[28], regs.gpr[29], regs.gpr[30], regs.gpr[31]); |
| printf(" SRR0 %016lx SRR1 %016lx\n", regs.srr0, regs.srr1); |
| #endif |
| } |
| |
| #ifdef GOARCH_amd64 |
| // retcodes: |
| // 0 : feature disabled |
| // 1 : feature enabled |
| // -1 : error getting feature state |
| static int cpu_feature_enabled(uint32_t function, uint32_t eax_bits, uint32_t ebx_bits, uint32_t ecx_bits, uint32_t edx_bits) |
| { |
| int kvmfd = open("/dev/kvm", O_RDWR); |
| if (kvmfd == -1) { |
| printf("failed to open /dev/kvm (%d)\n", errno); |
| return -1; |
| } |
| char buf[sizeof(struct kvm_cpuid2) + 128 * sizeof(struct kvm_cpuid_entry2)]; |
| memset(buf, 0, sizeof(buf)); |
| struct kvm_cpuid2* cpuid = (struct kvm_cpuid2*)buf; |
| cpuid->nent = 128; |
| ioctl(kvmfd, KVM_GET_SUPPORTED_CPUID, cpuid); |
| close(kvmfd); |
| for (uint32_t i = 0; i < cpuid->nent; i++) { |
| struct kvm_cpuid_entry2* entry = &cpuid->entries[i]; |
| if (entry->function == function && (!eax_bits || (entry->eax & eax_bits)) && (!ebx_bits || (entry->ebx & ebx_bits)) && (!ecx_bits || (entry->ecx & ecx_bits)) && (!edx_bits || (entry->edx & edx_bits))) |
| return 1; |
| } |
| return 0; |
| } |
| #endif |