/* * TPR optimization for 32-bit Windows guests (XP and Server 2003) * * Copyright (C) 2007-2008 Qumranet Technologies * Copyright (C) 2012 Jan Kiszka, Siemens AG * * This work is licensed under the terms of the GNU GPL version 2, or * (at your option) any later version. See the COPYING file in the * top-level directory. */ #include "sysemu/sysemu.h" #include "sysemu/cpus.h" #include "sysemu/kvm.h" #include "hw/i386/apic_internal.h" #define VAPIC_IO_PORT 0x7e #define VAPIC_CPU_SHIFT 7 #define ROM_BLOCK_SIZE 512 #define ROM_BLOCK_MASK (~(ROM_BLOCK_SIZE - 1)) typedef enum VAPICMode { VAPIC_INACTIVE = 0, VAPIC_ACTIVE = 1, VAPIC_STANDBY = 2, } VAPICMode; typedef struct VAPICHandlers { uint32_t set_tpr; uint32_t set_tpr_eax; uint32_t get_tpr[8]; uint32_t get_tpr_stack; } QEMU_PACKED VAPICHandlers; typedef struct GuestROMState { char signature[8]; uint32_t vaddr; uint32_t fixup_start; uint32_t fixup_end; uint32_t vapic_vaddr; uint32_t vapic_size; uint32_t vcpu_shift; uint32_t real_tpr_addr; VAPICHandlers up; VAPICHandlers mp; } QEMU_PACKED GuestROMState; typedef struct VAPICROMState { SysBusDevice busdev; MemoryRegion io; MemoryRegion rom; uint32_t state; uint32_t rom_state_paddr; uint32_t rom_state_vaddr; uint32_t vapic_paddr; uint32_t real_tpr_addr; GuestROMState rom_state; size_t rom_size; bool rom_mapped_writable; } VAPICROMState; #define TYPE_VAPIC "kvmvapic" #define VAPIC(obj) OBJECT_CHECK(VAPICROMState, (obj), TYPE_VAPIC) #define TPR_INSTR_ABS_MODRM 0x1 #define TPR_INSTR_MATCH_MODRM_REG 0x2 typedef struct TPRInstruction { uint8_t opcode; uint8_t modrm_reg; unsigned int flags; TPRAccess access; size_t length; off_t addr_offset; } TPRInstruction; /* must be sorted by length, shortest first */ static const TPRInstruction tpr_instr[] = { { /* mov abs to eax */ .opcode = 0xa1, .access = TPR_ACCESS_READ, .length = 5, .addr_offset = 1, }, { /* mov eax to abs */ .opcode = 0xa3, .access = TPR_ACCESS_WRITE, .length = 5, .addr_offset = 1, }, { /* mov r32 to r/m32 */ .opcode = 0x89, .flags = TPR_INSTR_ABS_MODRM, .access = TPR_ACCESS_WRITE, .length = 6, .addr_offset = 2, }, { /* mov r/m32 to r32 */ .opcode = 0x8b, .flags = TPR_INSTR_ABS_MODRM, .access = TPR_ACCESS_READ, .length = 6, .addr_offset = 2, }, { /* push r/m32 */ .opcode = 0xff, .modrm_reg = 6, .flags = TPR_INSTR_ABS_MODRM | TPR_INSTR_MATCH_MODRM_REG, .access = TPR_ACCESS_READ, .length = 6, .addr_offset = 2, }, { /* mov imm32, r/m32 (c7/0) */ .opcode = 0xc7, .modrm_reg = 0, .flags = TPR_INSTR_ABS_MODRM | TPR_INSTR_MATCH_MODRM_REG, .access = TPR_ACCESS_WRITE, .length = 10, .addr_offset = 2, }, }; static void read_guest_rom_state(VAPICROMState *s) { cpu_physical_memory_rw(s->rom_state_paddr, (void *)&s->rom_state, sizeof(GuestROMState), 0); } static void write_guest_rom_state(VAPICROMState *s) { cpu_physical_memory_rw(s->rom_state_paddr, (void *)&s->rom_state, sizeof(GuestROMState), 1); } static void update_guest_rom_state(VAPICROMState *s) { read_guest_rom_state(s); s->rom_state.real_tpr_addr = cpu_to_le32(s->real_tpr_addr); s->rom_state.vcpu_shift = cpu_to_le32(VAPIC_CPU_SHIFT); write_guest_rom_state(s); } static int find_real_tpr_addr(VAPICROMState *s, CPUX86State *env) { hwaddr paddr; target_ulong addr; if (s->state == VAPIC_ACTIVE) { return 0; } /* * If there is no prior TPR access instruction we could analyze (which is * the case after resume from hibernation), we need to scan the possible * virtual address space for the APIC mapping. */ for (addr = 0xfffff000; addr >= 0x80000000; addr -= TARGET_PAGE_SIZE) { paddr = cpu_get_phys_page_debug(env, addr); if (paddr != APIC_DEFAULT_ADDRESS) { continue; } s->real_tpr_addr = addr + 0x80; update_guest_rom_state(s); return 0; } return -1; } static uint8_t modrm_reg(uint8_t modrm) { return (modrm >> 3) & 7; } static bool is_abs_modrm(uint8_t modrm) { return (modrm & 0xc7) == 0x05; } static bool opcode_matches(uint8_t *opcode, const TPRInstruction *instr) { return opcode[0] == instr->opcode && (!(instr->flags & TPR_INSTR_ABS_MODRM) || is_abs_modrm(opcode[1])) && (!(instr->flags & TPR_INSTR_MATCH_MODRM_REG) || modrm_reg(opcode[1]) == instr->modrm_reg); } static int evaluate_tpr_instruction(VAPICROMState *s, CPUX86State *env, target_ulong *pip, TPRAccess access) { const TPRInstruction *instr; target_ulong ip = *pip; uint8_t opcode[2]; uint32_t real_tpr_addr; int i; if ((ip & 0xf0000000ULL) != 0x80000000ULL && (ip & 0xf0000000ULL) != 0xe0000000ULL) { return -1; } /* * Early Windows 2003 SMP initialization contains a * * mov imm32, r/m32 * * instruction that is patched by TPR optimization. The problem is that * RSP, used by the patched instruction, is zero, so the guest gets a * double fault and dies. */ if (env->regs[R_ESP] == 0) { return -1; } if (kvm_enabled() && !kvm_irqchip_in_kernel()) { /* * KVM without kernel-based TPR access reporting will pass an IP that * points after the accessing instruction. So we need to look backward * to find the reason. */ for (i = 0; i < ARRAY_SIZE(tpr_instr); i++) { instr = &tpr_instr[i]; if (instr->access != access) { continue; } if (cpu_memory_rw_debug(env, ip - instr->length, opcode, sizeof(opcode), 0) < 0) { return -1; } if (opcode_matches(opcode, instr)) { ip -= instr->length; goto instruction_ok; } } return -1; } else { if (cpu_memory_rw_debug(env, ip, opcode, sizeof(opcode), 0) < 0) { return -1; } for (i = 0; i < ARRAY_SIZE(tpr_instr); i++) { instr = &tpr_instr[i]; if (opcode_matches(opcode, instr)) { goto instruction_ok; } } return -1; } instruction_ok: /* * Grab the virtual TPR address from the instruction * and update the cached values. */ if (cpu_memory_rw_debug(env, ip + instr->addr_offset, (void *)&real_tpr_addr, sizeof(real_tpr_addr), 0) < 0) { return -1; } real_tpr_addr = le32_to_cpu(real_tpr_addr); if ((real_tpr_addr & 0xfff) != 0x80) { return -1; } s->real_tpr_addr = real_tpr_addr; update_guest_rom_state(s); *pip = ip; return 0; } static int update_rom_mapping(VAPICROMState *s, CPUX86State *env, target_ulong ip) { hwaddr paddr; uint32_t rom_state_vaddr; uint32_t pos, patch, offset; /* nothing to do if already activated */ if (s->state == VAPIC_ACTIVE) { return 0; } /* bail out if ROM init code was not executed (missing ROM?) */ if (s->state == VAPIC_INACTIVE) { return -1; } /* find out virtual address of the ROM */ rom_state_vaddr = s->rom_state_paddr + (ip & 0xf0000000); paddr = cpu_get_phys_page_debug(env, rom_state_vaddr); if (paddr == -1) { return -1; } paddr += rom_state_vaddr & ~TARGET_PAGE_MASK; if (paddr != s->rom_state_paddr) { return -1; } read_guest_rom_state(s); if (memcmp(s->rom_state.signature, "kvm aPiC", 8) != 0) { return -1; } s->rom_state_vaddr = rom_state_vaddr; /* fixup addresses in ROM if needed */ if (rom_state_vaddr == le32_to_cpu(s->rom_state.vaddr)) { return 0; } for (pos = le32_to_cpu(s->rom_state.fixup_start); pos < le32_to_cpu(s->rom_state.fixup_end); pos += 4) { cpu_physical_memory_rw(paddr + pos - s->rom_state.vaddr, (void *)&offset, sizeof(offset), 0); offset = le32_to_cpu(offset); cpu_physical_memory_rw(paddr + offset, (void *)&patch, sizeof(patch), 0); patch = le32_to_cpu(patch); patch += rom_state_vaddr - le32_to_cpu(s->rom_state.vaddr); patch = cpu_to_le32(patch); cpu_physical_memory_rw(paddr + offset, (void *)&patch, sizeof(patch), 1); } read_guest_rom_state(s); s->vapic_paddr = paddr + le32_to_cpu(s->rom_state.vapic_vaddr) - le32_to_cpu(s->rom_state.vaddr); return 0; } /* * Tries to read the unique processor number from the Kernel Processor Control * Region (KPCR) of 32-bit Windows XP and Server 2003. Returns -1 if the KPCR * cannot be accessed or is considered invalid. This also ensures that we are * not patching the wrong guest. */ static int get_kpcr_number(CPUX86State *env) { struct kpcr { uint8_t fill1[0x1c]; uint32_t self; uint8_t fill2[0x31]; uint8_t number; } QEMU_PACKED kpcr; if (cpu_memory_rw_debug(env, env->segs[R_FS].base, (void *)&kpcr, sizeof(kpcr), 0) < 0 || kpcr.self != env->segs[R_FS].base) { return -1; } return kpcr.number; } static int vapic_enable(VAPICROMState *s, CPUX86State *env) { int cpu_number = get_kpcr_number(env); hwaddr vapic_paddr; static const uint8_t enabled = 1; if (cpu_number < 0) { return -1; } vapic_paddr = s->vapic_paddr + (((hwaddr)cpu_number) << VAPIC_CPU_SHIFT); cpu_physical_memory_rw(vapic_paddr + offsetof(VAPICState, enabled), (void *)&enabled, sizeof(enabled), 1); apic_enable_vapic(env->apic_state, vapic_paddr); s->state = VAPIC_ACTIVE; return 0; } static void patch_byte(CPUX86State *env, target_ulong addr, uint8_t byte) { cpu_memory_rw_debug(env, addr, &byte, 1, 1); } static void patch_call(VAPICROMState *s, CPUX86State *env, target_ulong ip, uint32_t target) { uint32_t offset; offset = cpu_to_le32(target - ip - 5); patch_byte(env, ip, 0xe8); /* call near */ cpu_memory_rw_debug(env, ip + 1, (void *)&offset, sizeof(offset), 1); } static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong ip) { CPUState *cs = CPU(cpu); CPUX86State *env = &cpu->env; VAPICHandlers *handlers; uint8_t opcode[2]; uint32_t imm32; target_ulong current_pc = 0; target_ulong current_cs_base = 0; int current_flags = 0; if (smp_cpus == 1) { handlers = &s->rom_state.up; } else { handlers = &s->rom_state.mp; } if (!kvm_enabled()) { cpu_restore_state(env, env->mem_io_pc); cpu_get_tb_cpu_state(env, ¤t_pc, ¤t_cs_base, ¤t_flags); } pause_all_vcpus(); cpu_memory_rw_debug(env, ip, opcode, sizeof(opcode), 0); switch (opcode[0]) { case 0x89: /* mov r32 to r/m32 */ patch_byte(env, ip, 0x50 + modrm_reg(opcode[1])); /* push reg */ patch_call(s, env, ip + 1, handlers->set_tpr); break; case 0x8b: /* mov r/m32 to r32 */ patch_byte(env, ip, 0x90); patch_call(s, env, ip + 1, handlers->get_tpr[modrm_reg(opcode[1])]); break; case 0xa1: /* mov abs to eax */ patch_call(s, env, ip, handlers->get_tpr[0]); break; case 0xa3: /* mov eax to abs */ patch_call(s, env, ip, handlers->set_tpr_eax); break; case 0xc7: /* mov imm32, r/m32 (c7/0) */ patch_byte(env, ip, 0x68); /* push imm32 */ cpu_memory_rw_debug(env, ip + 6, (void *)&imm32, sizeof(imm32), 0); cpu_memory_rw_debug(env, ip + 1, (void *)&imm32, sizeof(imm32), 1); patch_call(s, env, ip + 5, handlers->set_tpr); break; case 0xff: /* push r/m32 */ patch_byte(env, ip, 0x50); /* push eax */ patch_call(s, env, ip + 1, handlers->get_tpr_stack); break; default: abort(); } resume_all_vcpus(); if (!kvm_enabled()) { cs->current_tb = NULL; tb_gen_code(env, current_pc, current_cs_base, current_flags, 1); cpu_resume_from_signal(env, NULL); } } void vapic_report_tpr_access(DeviceState *dev, CPUState *cs, target_ulong ip, TPRAccess access) { VAPICROMState *s = DO_UPCAST(VAPICROMState, busdev.qdev, dev); X86CPU *cpu = X86_CPU(cs); CPUX86State *env = &cpu->env; cpu_synchronize_state(env); if (evaluate_tpr_instruction(s, env, &ip, access) < 0) { if (s->state == VAPIC_ACTIVE) { vapic_enable(s, env); } return; } if (update_rom_mapping(s, env, ip) < 0) { return; } if (vapic_enable(s, env) < 0) { return; } patch_instruction(s, cpu, ip); } typedef struct VAPICEnableTPRReporting { DeviceState *apic; bool enable; } VAPICEnableTPRReporting; static void vapic_do_enable_tpr_reporting(void *data) { VAPICEnableTPRReporting *info = data; apic_enable_tpr_access_reporting(info->apic, info->enable); } static void vapic_enable_tpr_reporting(bool enable) { VAPICEnableTPRReporting info = { .enable = enable, }; X86CPU *cpu; CPUX86State *env; for (env = first_cpu; env != NULL; env = env->next_cpu) { cpu = x86_env_get_cpu(env); info.apic = env->apic_state; run_on_cpu(CPU(cpu), vapic_do_enable_tpr_reporting, &info); } } static void vapic_reset(DeviceState *dev) { VAPICROMState *s = DO_UPCAST(VAPICROMState, busdev.qdev, dev); if (s->state == VAPIC_ACTIVE) { s->state = VAPIC_STANDBY; } vapic_enable_tpr_reporting(false); } /* * Set the IRQ polling hypercalls to the supported variant: * - vmcall if using KVM in-kernel irqchip * - 32-bit VAPIC port write otherwise */ static int patch_hypercalls(VAPICROMState *s) { hwaddr rom_paddr = s->rom_state_paddr & ROM_BLOCK_MASK; static const uint8_t vmcall_pattern[] = { /* vmcall */ 0xb8, 0x1, 0, 0, 0, 0xf, 0x1, 0xc1 }; static const uint8_t outl_pattern[] = { /* nop; outl %eax,0x7e */ 0xb8, 0x1, 0, 0, 0, 0x90, 0xe7, 0x7e }; uint8_t alternates[2]; const uint8_t *pattern; const uint8_t *patch; int patches = 0; off_t pos; uint8_t *rom; rom = g_malloc(s->rom_size); cpu_physical_memory_rw(rom_paddr, rom, s->rom_size, 0); for (pos = 0; pos < s->rom_size - sizeof(vmcall_pattern); pos++) { if (kvm_irqchip_in_kernel()) { pattern = outl_pattern; alternates[0] = outl_pattern[7]; alternates[1] = outl_pattern[7]; patch = &vmcall_pattern[5]; } else { pattern = vmcall_pattern; alternates[0] = vmcall_pattern[7]; alternates[1] = 0xd9; /* AMD's VMMCALL */ patch = &outl_pattern[5]; } if (memcmp(rom + pos, pattern, 7) == 0 && (rom[pos + 7] == alternates[0] || rom[pos + 7] == alternates[1])) { cpu_physical_memory_rw(rom_paddr + pos + 5, (uint8_t *)patch, 3, 1); /* * Don't flush the tb here. Under ordinary conditions, the patched * calls are miles away from the current IP. Under malicious * conditions, the guest could trick us to crash. */ } } g_free(rom); if (patches != 0 && patches != 2) { return -1; } return 0; } /* * For TCG mode or the time KVM honors read-only memory regions, we need to * enable write access to the option ROM so that variables can be updated by * the guest. */ static void vapic_map_rom_writable(VAPICROMState *s) { hwaddr rom_paddr = s->rom_state_paddr & ROM_BLOCK_MASK; MemoryRegionSection section; MemoryRegion *as; size_t rom_size; uint8_t *ram; as = sysbus_address_space(&s->busdev); if (s->rom_mapped_writable) { memory_region_del_subregion(as, &s->rom); memory_region_destroy(&s->rom); } /* grab RAM memory region (region @rom_paddr may still be pc.rom) */ section = memory_region_find(as, 0, 1); /* read ROM size from RAM region */ ram = memory_region_get_ram_ptr(section.mr); rom_size = ram[rom_paddr + 2] * ROM_BLOCK_SIZE; s->rom_size = rom_size; /* We need to round to avoid creating subpages * from which we cannot run code. */ rom_size += rom_paddr & ~TARGET_PAGE_MASK; rom_paddr &= TARGET_PAGE_MASK; rom_size = TARGET_PAGE_ALIGN(rom_size); memory_region_init_alias(&s->rom, "kvmvapic-rom", section.mr, rom_paddr, rom_size); memory_region_add_subregion_overlap(as, rom_paddr, &s->rom, 1000); s->rom_mapped_writable = true; } static int vapic_prepare(VAPICROMState *s) { vapic_map_rom_writable(s); if (patch_hypercalls(s) < 0) { return -1; } vapic_enable_tpr_reporting(true); return 0; } static void vapic_write(void *opaque, hwaddr addr, uint64_t data, unsigned int size) { CPUX86State *env = cpu_single_env; hwaddr rom_paddr; VAPICROMState *s = opaque; cpu_synchronize_state(env); /* * The VAPIC supports two PIO-based hypercalls, both via port 0x7E. * o 16-bit write access: * Reports the option ROM initialization to the hypervisor. Written * value is the offset of the state structure in the ROM. * o 8-bit write access: * Reactivates the VAPIC after a guest hibernation, i.e. after the * option ROM content has been re-initialized by a guest power cycle. * o 32-bit write access: * Poll for pending IRQs, considering the current VAPIC state. */ switch (size) { case 2: if (s->state == VAPIC_INACTIVE) { rom_paddr = (env->segs[R_CS].base + env->eip) & ROM_BLOCK_MASK; s->rom_state_paddr = rom_paddr + data; s->state = VAPIC_STANDBY; } if (vapic_prepare(s) < 0) { s->state = VAPIC_INACTIVE; break; } break; case 1: if (kvm_enabled()) { /* * Disable triggering instruction in ROM by writing a NOP. * * We cannot do this in TCG mode as the reported IP is not * accurate. */ pause_all_vcpus(); patch_byte(env, env->eip - 2, 0x66); patch_byte(env, env->eip - 1, 0x90); resume_all_vcpus(); } if (s->state == VAPIC_ACTIVE) { break; } if (update_rom_mapping(s, env, env->eip) < 0) { break; } if (find_real_tpr_addr(s, env) < 0) { break; } vapic_enable(s, env); break; default: case 4: if (!kvm_irqchip_in_kernel()) { apic_poll_irq(env->apic_state); } break; } } static const MemoryRegionOps vapic_ops = { .write = vapic_write, .endianness = DEVICE_NATIVE_ENDIAN, }; static int vapic_init(SysBusDevice *dev) { VAPICROMState *s = VAPIC(dev); memory_region_init_io(&s->io, &vapic_ops, s, "kvmvapic", 2); sysbus_add_io(dev, VAPIC_IO_PORT, &s->io); sysbus_init_ioports(dev, VAPIC_IO_PORT, 2); option_rom[nb_option_roms].name = "kvmvapic.bin"; option_rom[nb_option_roms].bootindex = -1; nb_option_roms++; return 0; } static void do_vapic_enable(void *data) { VAPICROMState *s = data; vapic_enable(s, first_cpu); } static int vapic_post_load(void *opaque, int version_id) { VAPICROMState *s = opaque; uint8_t *zero; /* * The old implementation of qemu-kvm did not provide the state * VAPIC_STANDBY. Reconstruct it. */ if (s->state == VAPIC_INACTIVE && s->rom_state_paddr != 0) { s->state = VAPIC_STANDBY; } if (s->state != VAPIC_INACTIVE) { if (vapic_prepare(s) < 0) { return -1; } } if (s->state == VAPIC_ACTIVE) { if (smp_cpus == 1) { run_on_cpu(ENV_GET_CPU(first_cpu), do_vapic_enable, s); } else { zero = g_malloc0(s->rom_state.vapic_size); cpu_physical_memory_rw(s->vapic_paddr, zero, s->rom_state.vapic_size, 1); g_free(zero); } } return 0; } static const VMStateDescription vmstate_handlers = { .name = "kvmvapic-handlers", .version_id = 1, .minimum_version_id = 1, .minimum_version_id_old = 1, .fields = (VMStateField[]) { VMSTATE_UINT32(set_tpr, VAPICHandlers), VMSTATE_UINT32(set_tpr_eax, VAPICHandlers), VMSTATE_UINT32_ARRAY(get_tpr, VAPICHandlers, 8), VMSTATE_UINT32(get_tpr_stack, VAPICHandlers), VMSTATE_END_OF_LIST() } }; static const VMStateDescription vmstate_guest_rom = { .name = "kvmvapic-guest-rom", .version_id = 1, .minimum_version_id = 1, .minimum_version_id_old = 1, .fields = (VMStateField[]) { VMSTATE_UNUSED(8), /* signature */ VMSTATE_UINT32(vaddr, GuestROMState), VMSTATE_UINT32(fixup_start, GuestROMState), VMSTATE_UINT32(fixup_end, GuestROMState), VMSTATE_UINT32(vapic_vaddr, GuestROMState), VMSTATE_UINT32(vapic_size, GuestROMState), VMSTATE_UINT32(vcpu_shift, GuestROMState), VMSTATE_UINT32(real_tpr_addr, GuestROMState), VMSTATE_STRUCT(up, GuestROMState, 0, vmstate_handlers, VAPICHandlers), VMSTATE_STRUCT(mp, GuestROMState, 0, vmstate_handlers, VAPICHandlers), VMSTATE_END_OF_LIST() } }; static const VMStateDescription vmstate_vapic = { .name = "kvm-tpr-opt", /* compatible with qemu-kvm VAPIC */ .version_id = 1, .minimum_version_id = 1, .minimum_version_id_old = 1, .post_load = vapic_post_load, .fields = (VMStateField[]) { VMSTATE_STRUCT(rom_state, VAPICROMState, 0, vmstate_guest_rom, GuestROMState), VMSTATE_UINT32(state, VAPICROMState), VMSTATE_UINT32(real_tpr_addr, VAPICROMState), VMSTATE_UINT32(rom_state_vaddr, VAPICROMState), VMSTATE_UINT32(vapic_paddr, VAPICROMState), VMSTATE_UINT32(rom_state_paddr, VAPICROMState), VMSTATE_END_OF_LIST() } }; static void vapic_class_init(ObjectClass *klass, void *data) { SysBusDeviceClass *sc = SYS_BUS_DEVICE_CLASS(klass); DeviceClass *dc = DEVICE_CLASS(klass); dc->no_user = 1; dc->reset = vapic_reset; dc->vmsd = &vmstate_vapic; sc->init = vapic_init; } static const TypeInfo vapic_type = { .name = TYPE_VAPIC, .parent = TYPE_SYS_BUS_DEVICE, .instance_size = sizeof(VAPICROMState), .class_init = vapic_class_init, }; static void vapic_register(void) { type_register_static(&vapic_type); } type_init(vapic_register);