xref: /openbmc/qemu/hw/i386/vapic.c (revision 4921d0a7)
1 /*
2  * TPR optimization for 32-bit Windows guests (XP and Server 2003)
3  *
4  * Copyright (C) 2007-2008 Qumranet Technologies
5  * Copyright (C) 2012      Jan Kiszka, Siemens AG
6  *
7  * This work is licensed under the terms of the GNU GPL version 2, or
8  * (at your option) any later version. See the COPYING file in the
9  * top-level directory.
10  */
11 
12 #include "qemu/osdep.h"
13 #include "qemu/module.h"
14 #include "sysemu/sysemu.h"
15 #include "sysemu/cpus.h"
16 #include "sysemu/hw_accel.h"
17 #include "sysemu/kvm.h"
18 #include "sysemu/runstate.h"
19 #include "exec/address-spaces.h"
20 #include "hw/i386/apic_internal.h"
21 #include "hw/sysbus.h"
22 #include "hw/boards.h"
23 #include "migration/vmstate.h"
24 #include "qom/object.h"
25 
26 #define VAPIC_IO_PORT           0x7e
27 
28 #define VAPIC_CPU_SHIFT         7
29 
30 #define ROM_BLOCK_SIZE          512
31 #define ROM_BLOCK_MASK          (~(ROM_BLOCK_SIZE - 1))
32 
33 typedef enum VAPICMode {
34     VAPIC_INACTIVE = 0,
35     VAPIC_ACTIVE   = 1,
36     VAPIC_STANDBY  = 2,
37 } VAPICMode;
38 
39 typedef struct VAPICHandlers {
40     uint32_t set_tpr;
41     uint32_t set_tpr_eax;
42     uint32_t get_tpr[8];
43     uint32_t get_tpr_stack;
44 } QEMU_PACKED VAPICHandlers;
45 
46 typedef struct GuestROMState {
47     char signature[8];
48     uint32_t vaddr;
49     uint32_t fixup_start;
50     uint32_t fixup_end;
51     uint32_t vapic_vaddr;
52     uint32_t vapic_size;
53     uint32_t vcpu_shift;
54     uint32_t real_tpr_addr;
55     VAPICHandlers up;
56     VAPICHandlers mp;
57 } QEMU_PACKED GuestROMState;
58 
59 struct VAPICROMState {
60     SysBusDevice busdev;
61 
62     MemoryRegion io;
63     MemoryRegion rom;
64     uint32_t state;
65     uint32_t rom_state_paddr;
66     uint32_t rom_state_vaddr;
67     uint32_t vapic_paddr;
68     uint32_t real_tpr_addr;
69     GuestROMState rom_state;
70     size_t rom_size;
71     bool rom_mapped_writable;
72     VMChangeStateEntry *vmsentry;
73 };
74 
75 #define TYPE_VAPIC "kvmvapic"
76 OBJECT_DECLARE_SIMPLE_TYPE(VAPICROMState, VAPIC)
77 
78 #define TPR_INSTR_ABS_MODRM             0x1
79 #define TPR_INSTR_MATCH_MODRM_REG       0x2
80 
81 typedef struct TPRInstruction {
82     uint8_t opcode;
83     uint8_t modrm_reg;
84     unsigned int flags;
85     TPRAccess access;
86     size_t length;
87     off_t addr_offset;
88 } TPRInstruction;
89 
90 /* must be sorted by length, shortest first */
91 static const TPRInstruction tpr_instr[] = {
92     { /* mov abs to eax */
93         .opcode = 0xa1,
94         .access = TPR_ACCESS_READ,
95         .length = 5,
96         .addr_offset = 1,
97     },
98     { /* mov eax to abs */
99         .opcode = 0xa3,
100         .access = TPR_ACCESS_WRITE,
101         .length = 5,
102         .addr_offset = 1,
103     },
104     { /* mov r32 to r/m32 */
105         .opcode = 0x89,
106         .flags = TPR_INSTR_ABS_MODRM,
107         .access = TPR_ACCESS_WRITE,
108         .length = 6,
109         .addr_offset = 2,
110     },
111     { /* mov r/m32 to r32 */
112         .opcode = 0x8b,
113         .flags = TPR_INSTR_ABS_MODRM,
114         .access = TPR_ACCESS_READ,
115         .length = 6,
116         .addr_offset = 2,
117     },
118     { /* push r/m32 */
119         .opcode = 0xff,
120         .modrm_reg = 6,
121         .flags = TPR_INSTR_ABS_MODRM | TPR_INSTR_MATCH_MODRM_REG,
122         .access = TPR_ACCESS_READ,
123         .length = 6,
124         .addr_offset = 2,
125     },
126     { /* mov imm32, r/m32 (c7/0) */
127         .opcode = 0xc7,
128         .modrm_reg = 0,
129         .flags = TPR_INSTR_ABS_MODRM | TPR_INSTR_MATCH_MODRM_REG,
130         .access = TPR_ACCESS_WRITE,
131         .length = 10,
132         .addr_offset = 2,
133     },
134 };
135 
136 static void read_guest_rom_state(VAPICROMState *s)
137 {
138     cpu_physical_memory_read(s->rom_state_paddr, &s->rom_state,
139                              sizeof(GuestROMState));
140 }
141 
142 static void write_guest_rom_state(VAPICROMState *s)
143 {
144     cpu_physical_memory_write(s->rom_state_paddr, &s->rom_state,
145                               sizeof(GuestROMState));
146 }
147 
148 static void update_guest_rom_state(VAPICROMState *s)
149 {
150     read_guest_rom_state(s);
151 
152     s->rom_state.real_tpr_addr = cpu_to_le32(s->real_tpr_addr);
153     s->rom_state.vcpu_shift = cpu_to_le32(VAPIC_CPU_SHIFT);
154 
155     write_guest_rom_state(s);
156 }
157 
158 static int find_real_tpr_addr(VAPICROMState *s, CPUX86State *env)
159 {
160     CPUState *cs = env_cpu(env);
161     hwaddr paddr;
162     target_ulong addr;
163 
164     if (s->state == VAPIC_ACTIVE) {
165         return 0;
166     }
167     /*
168      * If there is no prior TPR access instruction we could analyze (which is
169      * the case after resume from hibernation), we need to scan the possible
170      * virtual address space for the APIC mapping.
171      */
172     for (addr = 0xfffff000; addr >= 0x80000000; addr -= TARGET_PAGE_SIZE) {
173         paddr = cpu_get_phys_page_debug(cs, addr);
174         if (paddr != APIC_DEFAULT_ADDRESS) {
175             continue;
176         }
177         s->real_tpr_addr = addr + 0x80;
178         update_guest_rom_state(s);
179         return 0;
180     }
181     return -1;
182 }
183 
184 static uint8_t modrm_reg(uint8_t modrm)
185 {
186     return (modrm >> 3) & 7;
187 }
188 
189 static bool is_abs_modrm(uint8_t modrm)
190 {
191     return (modrm & 0xc7) == 0x05;
192 }
193 
194 static bool opcode_matches(uint8_t *opcode, const TPRInstruction *instr)
195 {
196     return opcode[0] == instr->opcode &&
197         (!(instr->flags & TPR_INSTR_ABS_MODRM) || is_abs_modrm(opcode[1])) &&
198         (!(instr->flags & TPR_INSTR_MATCH_MODRM_REG) ||
199          modrm_reg(opcode[1]) == instr->modrm_reg);
200 }
201 
202 static int evaluate_tpr_instruction(VAPICROMState *s, X86CPU *cpu,
203                                     target_ulong *pip, TPRAccess access)
204 {
205     CPUState *cs = CPU(cpu);
206     const TPRInstruction *instr;
207     target_ulong ip = *pip;
208     uint8_t opcode[2];
209     uint32_t real_tpr_addr;
210     int i;
211 
212     if ((ip & 0xf0000000ULL) != 0x80000000ULL &&
213         (ip & 0xf0000000ULL) != 0xe0000000ULL) {
214         return -1;
215     }
216 
217     /*
218      * Early Windows 2003 SMP initialization contains a
219      *
220      *   mov imm32, r/m32
221      *
222      * instruction that is patched by TPR optimization. The problem is that
223      * RSP, used by the patched instruction, is zero, so the guest gets a
224      * double fault and dies.
225      */
226     if (cpu->env.regs[R_ESP] == 0) {
227         return -1;
228     }
229 
230     if (kvm_enabled() && !kvm_irqchip_in_kernel()) {
231         /*
232          * KVM without kernel-based TPR access reporting will pass an IP that
233          * points after the accessing instruction. So we need to look backward
234          * to find the reason.
235          */
236         for (i = 0; i < ARRAY_SIZE(tpr_instr); i++) {
237             instr = &tpr_instr[i];
238             if (instr->access != access) {
239                 continue;
240             }
241             if (cpu_memory_rw_debug(cs, ip - instr->length, opcode,
242                                     sizeof(opcode), 0) < 0) {
243                 return -1;
244             }
245             if (opcode_matches(opcode, instr)) {
246                 ip -= instr->length;
247                 goto instruction_ok;
248             }
249         }
250         return -1;
251     } else {
252         if (cpu_memory_rw_debug(cs, ip, opcode, sizeof(opcode), 0) < 0) {
253             return -1;
254         }
255         for (i = 0; i < ARRAY_SIZE(tpr_instr); i++) {
256             instr = &tpr_instr[i];
257             if (opcode_matches(opcode, instr)) {
258                 goto instruction_ok;
259             }
260         }
261         return -1;
262     }
263 
264 instruction_ok:
265     /*
266      * Grab the virtual TPR address from the instruction
267      * and update the cached values.
268      */
269     if (cpu_memory_rw_debug(cs, ip + instr->addr_offset,
270                             (void *)&real_tpr_addr,
271                             sizeof(real_tpr_addr), 0) < 0) {
272         return -1;
273     }
274     real_tpr_addr = le32_to_cpu(real_tpr_addr);
275     if ((real_tpr_addr & 0xfff) != 0x80) {
276         return -1;
277     }
278     s->real_tpr_addr = real_tpr_addr;
279     update_guest_rom_state(s);
280 
281     *pip = ip;
282     return 0;
283 }
284 
285 static int update_rom_mapping(VAPICROMState *s, CPUX86State *env, target_ulong ip)
286 {
287     CPUState *cs = env_cpu(env);
288     hwaddr paddr;
289     uint32_t rom_state_vaddr;
290     uint32_t pos, patch, offset;
291 
292     /* nothing to do if already activated */
293     if (s->state == VAPIC_ACTIVE) {
294         return 0;
295     }
296 
297     /* bail out if ROM init code was not executed (missing ROM?) */
298     if (s->state == VAPIC_INACTIVE) {
299         return -1;
300     }
301 
302     /* find out virtual address of the ROM */
303     rom_state_vaddr = s->rom_state_paddr + (ip & 0xf0000000);
304     paddr = cpu_get_phys_page_debug(cs, rom_state_vaddr);
305     if (paddr == -1) {
306         return -1;
307     }
308     paddr += rom_state_vaddr & ~TARGET_PAGE_MASK;
309     if (paddr != s->rom_state_paddr) {
310         return -1;
311     }
312     read_guest_rom_state(s);
313     if (memcmp(s->rom_state.signature, "kvm aPiC", 8) != 0) {
314         return -1;
315     }
316     s->rom_state_vaddr = rom_state_vaddr;
317 
318     /* fixup addresses in ROM if needed */
319     if (rom_state_vaddr == le32_to_cpu(s->rom_state.vaddr)) {
320         return 0;
321     }
322     for (pos = le32_to_cpu(s->rom_state.fixup_start);
323          pos < le32_to_cpu(s->rom_state.fixup_end);
324          pos += 4) {
325         cpu_physical_memory_read(paddr + pos - s->rom_state.vaddr,
326                                  &offset, sizeof(offset));
327         offset = le32_to_cpu(offset);
328         cpu_physical_memory_read(paddr + offset, &patch, sizeof(patch));
329         patch = le32_to_cpu(patch);
330         patch += rom_state_vaddr - le32_to_cpu(s->rom_state.vaddr);
331         patch = cpu_to_le32(patch);
332         cpu_physical_memory_write(paddr + offset, &patch, sizeof(patch));
333     }
334     read_guest_rom_state(s);
335     s->vapic_paddr = paddr + le32_to_cpu(s->rom_state.vapic_vaddr) -
336         le32_to_cpu(s->rom_state.vaddr);
337 
338     return 0;
339 }
340 
341 /*
342  * Tries to read the unique processor number from the Kernel Processor Control
343  * Region (KPCR) of 32-bit Windows XP and Server 2003. Returns -1 if the KPCR
344  * cannot be accessed or is considered invalid. This also ensures that we are
345  * not patching the wrong guest.
346  */
347 static int get_kpcr_number(X86CPU *cpu)
348 {
349     CPUX86State *env = &cpu->env;
350     struct kpcr {
351         uint8_t  fill1[0x1c];
352         uint32_t self;
353         uint8_t  fill2[0x31];
354         uint8_t  number;
355     } QEMU_PACKED kpcr;
356 
357     if (cpu_memory_rw_debug(CPU(cpu), env->segs[R_FS].base,
358                             (void *)&kpcr, sizeof(kpcr), 0) < 0 ||
359         kpcr.self != env->segs[R_FS].base) {
360         return -1;
361     }
362     return kpcr.number;
363 }
364 
365 static int vapic_enable(VAPICROMState *s, X86CPU *cpu)
366 {
367     int cpu_number = get_kpcr_number(cpu);
368     hwaddr vapic_paddr;
369     static const uint8_t enabled = 1;
370 
371     if (cpu_number < 0) {
372         return -1;
373     }
374     vapic_paddr = s->vapic_paddr +
375         (((hwaddr)cpu_number) << VAPIC_CPU_SHIFT);
376     cpu_physical_memory_write(vapic_paddr + offsetof(VAPICState, enabled),
377                               &enabled, sizeof(enabled));
378     apic_enable_vapic(cpu->apic_state, vapic_paddr);
379 
380     s->state = VAPIC_ACTIVE;
381 
382     return 0;
383 }
384 
385 static void patch_byte(X86CPU *cpu, target_ulong addr, uint8_t byte)
386 {
387     cpu_memory_rw_debug(CPU(cpu), addr, &byte, 1, 1);
388 }
389 
390 static void patch_call(X86CPU *cpu, target_ulong ip, uint32_t target)
391 {
392     uint32_t offset;
393 
394     offset = cpu_to_le32(target - ip - 5);
395     patch_byte(cpu, ip, 0xe8); /* call near */
396     cpu_memory_rw_debug(CPU(cpu), ip + 1, (void *)&offset, sizeof(offset), 1);
397 }
398 
399 typedef struct PatchInfo {
400     VAPICHandlers *handler;
401     target_ulong ip;
402 } PatchInfo;
403 
404 static void do_patch_instruction(CPUState *cs, run_on_cpu_data data)
405 {
406     X86CPU *x86_cpu = X86_CPU(cs);
407     PatchInfo *info = (PatchInfo *) data.host_ptr;
408     VAPICHandlers *handlers = info->handler;
409     target_ulong ip = info->ip;
410     uint8_t opcode[2];
411     uint32_t imm32 = 0;
412 
413     cpu_memory_rw_debug(cs, ip, opcode, sizeof(opcode), 0);
414 
415     switch (opcode[0]) {
416     case 0x89: /* mov r32 to r/m32 */
417         patch_byte(x86_cpu, ip, 0x50 + modrm_reg(opcode[1]));  /* push reg */
418         patch_call(x86_cpu, ip + 1, handlers->set_tpr);
419         break;
420     case 0x8b: /* mov r/m32 to r32 */
421         patch_byte(x86_cpu, ip, 0x90);
422         patch_call(x86_cpu, ip + 1, handlers->get_tpr[modrm_reg(opcode[1])]);
423         break;
424     case 0xa1: /* mov abs to eax */
425         patch_call(x86_cpu, ip, handlers->get_tpr[0]);
426         break;
427     case 0xa3: /* mov eax to abs */
428         patch_call(x86_cpu, ip, handlers->set_tpr_eax);
429         break;
430     case 0xc7: /* mov imm32, r/m32 (c7/0) */
431         patch_byte(x86_cpu, ip, 0x68);  /* push imm32 */
432         cpu_memory_rw_debug(cs, ip + 6, (void *)&imm32, sizeof(imm32), 0);
433         cpu_memory_rw_debug(cs, ip + 1, (void *)&imm32, sizeof(imm32), 1);
434         patch_call(x86_cpu, ip + 5, handlers->set_tpr);
435         break;
436     case 0xff: /* push r/m32 */
437         patch_byte(x86_cpu, ip, 0x50); /* push eax */
438         patch_call(x86_cpu, ip + 1, handlers->get_tpr_stack);
439         break;
440     default:
441         abort();
442     }
443 
444     g_free(info);
445 }
446 
447 static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong ip)
448 {
449     MachineState *ms = MACHINE(qdev_get_machine());
450     CPUState *cs = CPU(cpu);
451     VAPICHandlers *handlers;
452     PatchInfo *info;
453 
454     if (ms->smp.cpus == 1) {
455         handlers = &s->rom_state.up;
456     } else {
457         handlers = &s->rom_state.mp;
458     }
459 
460     info  = g_new(PatchInfo, 1);
461     info->handler = handlers;
462     info->ip = ip;
463 
464     async_safe_run_on_cpu(cs, do_patch_instruction, RUN_ON_CPU_HOST_PTR(info));
465 }
466 
467 void vapic_report_tpr_access(DeviceState *dev, CPUState *cs, target_ulong ip,
468                              TPRAccess access)
469 {
470     VAPICROMState *s = VAPIC(dev);
471     X86CPU *cpu = X86_CPU(cs);
472     CPUX86State *env = &cpu->env;
473 
474     cpu_synchronize_state(cs);
475 
476     if (evaluate_tpr_instruction(s, cpu, &ip, access) < 0) {
477         if (s->state == VAPIC_ACTIVE) {
478             vapic_enable(s, cpu);
479         }
480         return;
481     }
482     if (update_rom_mapping(s, env, ip) < 0) {
483         return;
484     }
485     if (vapic_enable(s, cpu) < 0) {
486         return;
487     }
488     patch_instruction(s, cpu, ip);
489 }
490 
491 typedef struct VAPICEnableTPRReporting {
492     DeviceState *apic;
493     bool enable;
494 } VAPICEnableTPRReporting;
495 
496 static void vapic_do_enable_tpr_reporting(CPUState *cpu, run_on_cpu_data data)
497 {
498     VAPICEnableTPRReporting *info = data.host_ptr;
499     apic_enable_tpr_access_reporting(info->apic, info->enable);
500 }
501 
502 static void vapic_enable_tpr_reporting(bool enable)
503 {
504     VAPICEnableTPRReporting info = {
505         .enable = enable,
506     };
507     CPUState *cs;
508     X86CPU *cpu;
509 
510     CPU_FOREACH(cs) {
511         cpu = X86_CPU(cs);
512         info.apic = cpu->apic_state;
513         run_on_cpu(cs, vapic_do_enable_tpr_reporting, RUN_ON_CPU_HOST_PTR(&info));
514     }
515 }
516 
517 static void vapic_reset(DeviceState *dev)
518 {
519     VAPICROMState *s = VAPIC(dev);
520 
521     s->state = VAPIC_INACTIVE;
522     s->rom_state_paddr = 0;
523     vapic_enable_tpr_reporting(false);
524 }
525 
526 /*
527  * Set the IRQ polling hypercalls to the supported variant:
528  *  - vmcall if using KVM in-kernel irqchip
529  *  - 32-bit VAPIC port write otherwise
530  */
531 static int patch_hypercalls(VAPICROMState *s)
532 {
533     hwaddr rom_paddr = s->rom_state_paddr & ROM_BLOCK_MASK;
534     static const uint8_t vmcall_pattern[] = { /* vmcall */
535         0xb8, 0x1, 0, 0, 0, 0xf, 0x1, 0xc1
536     };
537     static const uint8_t outl_pattern[] = { /* nop; outl %eax,0x7e */
538         0xb8, 0x1, 0, 0, 0, 0x90, 0xe7, 0x7e
539     };
540     uint8_t alternates[2];
541     const uint8_t *pattern;
542     const uint8_t *patch;
543     off_t pos;
544     uint8_t *rom;
545 
546     rom = g_malloc(s->rom_size);
547     cpu_physical_memory_read(rom_paddr, rom, s->rom_size);
548 
549     for (pos = 0; pos < s->rom_size - sizeof(vmcall_pattern); pos++) {
550         if (kvm_irqchip_in_kernel()) {
551             pattern = outl_pattern;
552             alternates[0] = outl_pattern[7];
553             alternates[1] = outl_pattern[7];
554             patch = &vmcall_pattern[5];
555         } else {
556             pattern = vmcall_pattern;
557             alternates[0] = vmcall_pattern[7];
558             alternates[1] = 0xd9; /* AMD's VMMCALL */
559             patch = &outl_pattern[5];
560         }
561         if (memcmp(rom + pos, pattern, 7) == 0 &&
562             (rom[pos + 7] == alternates[0] || rom[pos + 7] == alternates[1])) {
563             cpu_physical_memory_write(rom_paddr + pos + 5, patch, 3);
564             /*
565              * Don't flush the tb here. Under ordinary conditions, the patched
566              * calls are miles away from the current IP. Under malicious
567              * conditions, the guest could trick us to crash.
568              */
569         }
570     }
571 
572     g_free(rom);
573     return 0;
574 }
575 
576 /*
577  * For TCG mode or the time KVM honors read-only memory regions, we need to
578  * enable write access to the option ROM so that variables can be updated by
579  * the guest.
580  */
581 static int vapic_map_rom_writable(VAPICROMState *s)
582 {
583     hwaddr rom_paddr = s->rom_state_paddr & ROM_BLOCK_MASK;
584     MemoryRegionSection section;
585     MemoryRegion *mr = get_system_memory();
586     size_t rom_size;
587     uint8_t *ram;
588 
589     if (s->rom_mapped_writable) {
590         memory_region_del_subregion(mr, &s->rom);
591         object_unparent(OBJECT(&s->rom));
592     }
593 
594     /* grab RAM memory region (region @rom_paddr may still be pc.rom) */
595     section = memory_region_find(mr, 0, 1);
596 
597     /* read ROM size from RAM region */
598     if (rom_paddr + 2 >= memory_region_size(section.mr)) {
599         return -1;
600     }
601     ram = memory_region_get_ram_ptr(section.mr);
602     rom_size = ram[rom_paddr + 2] * ROM_BLOCK_SIZE;
603     if (rom_size == 0) {
604         return -1;
605     }
606     s->rom_size = rom_size;
607 
608     /* We need to round to avoid creating subpages
609      * from which we cannot run code. */
610     rom_size += rom_paddr & ~TARGET_PAGE_MASK;
611     rom_paddr &= TARGET_PAGE_MASK;
612     rom_size = TARGET_PAGE_ALIGN(rom_size);
613 
614     memory_region_init_alias(&s->rom, OBJECT(s), "kvmvapic-rom", section.mr,
615                              rom_paddr, rom_size);
616     memory_region_add_subregion_overlap(mr, rom_paddr, &s->rom, 1000);
617     s->rom_mapped_writable = true;
618     memory_region_unref(section.mr);
619 
620     return 0;
621 }
622 
623 static int vapic_prepare(VAPICROMState *s)
624 {
625     if (vapic_map_rom_writable(s) < 0) {
626         return -1;
627     }
628 
629     if (patch_hypercalls(s) < 0) {
630         return -1;
631     }
632 
633     vapic_enable_tpr_reporting(true);
634 
635     return 0;
636 }
637 
638 static void vapic_write(void *opaque, hwaddr addr, uint64_t data,
639                         unsigned int size)
640 {
641     VAPICROMState *s = opaque;
642     X86CPU *cpu;
643     CPUX86State *env;
644     hwaddr rom_paddr;
645 
646     if (!current_cpu) {
647         return;
648     }
649 
650     cpu_synchronize_state(current_cpu);
651     cpu = X86_CPU(current_cpu);
652     env = &cpu->env;
653 
654     /*
655      * The VAPIC supports two PIO-based hypercalls, both via port 0x7E.
656      *  o 16-bit write access:
657      *    Reports the option ROM initialization to the hypervisor. Written
658      *    value is the offset of the state structure in the ROM.
659      *  o 8-bit write access:
660      *    Reactivates the VAPIC after a guest hibernation, i.e. after the
661      *    option ROM content has been re-initialized by a guest power cycle.
662      *  o 32-bit write access:
663      *    Poll for pending IRQs, considering the current VAPIC state.
664      */
665     switch (size) {
666     case 2:
667         if (s->state == VAPIC_INACTIVE) {
668             rom_paddr = (env->segs[R_CS].base + env->eip) & ROM_BLOCK_MASK;
669             s->rom_state_paddr = rom_paddr + data;
670 
671             s->state = VAPIC_STANDBY;
672         }
673         if (vapic_prepare(s) < 0) {
674             s->state = VAPIC_INACTIVE;
675             s->rom_state_paddr = 0;
676             break;
677         }
678         break;
679     case 1:
680         if (kvm_enabled()) {
681             /*
682              * Disable triggering instruction in ROM by writing a NOP.
683              *
684              * We cannot do this in TCG mode as the reported IP is not
685              * accurate.
686              */
687             pause_all_vcpus();
688             patch_byte(cpu, env->eip - 2, 0x66);
689             patch_byte(cpu, env->eip - 1, 0x90);
690             resume_all_vcpus();
691         }
692 
693         if (s->state == VAPIC_ACTIVE) {
694             break;
695         }
696         if (update_rom_mapping(s, env, env->eip) < 0) {
697             break;
698         }
699         if (find_real_tpr_addr(s, env) < 0) {
700             break;
701         }
702         vapic_enable(s, cpu);
703         break;
704     default:
705     case 4:
706         if (!kvm_irqchip_in_kernel()) {
707             apic_poll_irq(cpu->apic_state);
708         }
709         break;
710     }
711 }
712 
713 static uint64_t vapic_read(void *opaque, hwaddr addr, unsigned size)
714 {
715     return 0xffffffff;
716 }
717 
718 static const MemoryRegionOps vapic_ops = {
719     .write = vapic_write,
720     .read = vapic_read,
721     .endianness = DEVICE_NATIVE_ENDIAN,
722 };
723 
724 static void vapic_realize(DeviceState *dev, Error **errp)
725 {
726     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
727     VAPICROMState *s = VAPIC(dev);
728 
729     memory_region_init_io(&s->io, OBJECT(s), &vapic_ops, s, "kvmvapic", 2);
730     memory_region_add_subregion(get_system_io(), VAPIC_IO_PORT, &s->io);
731     sysbus_init_ioports(sbd, VAPIC_IO_PORT, 2);
732 
733     option_rom[nb_option_roms].name = "kvmvapic.bin";
734     option_rom[nb_option_roms].bootindex = -1;
735     nb_option_roms++;
736 }
737 
738 static void do_vapic_enable(CPUState *cs, run_on_cpu_data data)
739 {
740     VAPICROMState *s = data.host_ptr;
741     X86CPU *cpu = X86_CPU(cs);
742 
743     static const uint8_t enabled = 1;
744     cpu_physical_memory_write(s->vapic_paddr + offsetof(VAPICState, enabled),
745                               &enabled, sizeof(enabled));
746     apic_enable_vapic(cpu->apic_state, s->vapic_paddr);
747     s->state = VAPIC_ACTIVE;
748 }
749 
750 static void vapic_vm_state_change(void *opaque, bool running, RunState state)
751 {
752     MachineState *ms = MACHINE(qdev_get_machine());
753     VAPICROMState *s = opaque;
754     uint8_t *zero;
755 
756     if (!running) {
757         return;
758     }
759 
760     if (s->state == VAPIC_ACTIVE) {
761         if (ms->smp.cpus == 1) {
762             run_on_cpu(first_cpu, do_vapic_enable, RUN_ON_CPU_HOST_PTR(s));
763         } else {
764             zero = g_malloc0(s->rom_state.vapic_size);
765             cpu_physical_memory_write(s->vapic_paddr, zero,
766                                       s->rom_state.vapic_size);
767             g_free(zero);
768         }
769     }
770 
771     qemu_del_vm_change_state_handler(s->vmsentry);
772     s->vmsentry = NULL;
773 }
774 
775 static int vapic_post_load(void *opaque, int version_id)
776 {
777     VAPICROMState *s = opaque;
778 
779     /*
780      * The old implementation of qemu-kvm did not provide the state
781      * VAPIC_STANDBY. Reconstruct it.
782      */
783     if (s->state == VAPIC_INACTIVE && s->rom_state_paddr != 0) {
784         s->state = VAPIC_STANDBY;
785     }
786 
787     if (s->state != VAPIC_INACTIVE) {
788         if (vapic_prepare(s) < 0) {
789             return -1;
790         }
791     }
792 
793     if (!s->vmsentry) {
794         s->vmsentry =
795             qemu_add_vm_change_state_handler(vapic_vm_state_change, s);
796     }
797     return 0;
798 }
799 
800 static const VMStateDescription vmstate_handlers = {
801     .name = "kvmvapic-handlers",
802     .version_id = 1,
803     .minimum_version_id = 1,
804     .fields = (const VMStateField[]) {
805         VMSTATE_UINT32(set_tpr, VAPICHandlers),
806         VMSTATE_UINT32(set_tpr_eax, VAPICHandlers),
807         VMSTATE_UINT32_ARRAY(get_tpr, VAPICHandlers, 8),
808         VMSTATE_UINT32(get_tpr_stack, VAPICHandlers),
809         VMSTATE_END_OF_LIST()
810     }
811 };
812 
813 static const VMStateDescription vmstate_guest_rom = {
814     .name = "kvmvapic-guest-rom",
815     .version_id = 1,
816     .minimum_version_id = 1,
817     .fields = (const VMStateField[]) {
818         VMSTATE_UNUSED(8),     /* signature */
819         VMSTATE_UINT32(vaddr, GuestROMState),
820         VMSTATE_UINT32(fixup_start, GuestROMState),
821         VMSTATE_UINT32(fixup_end, GuestROMState),
822         VMSTATE_UINT32(vapic_vaddr, GuestROMState),
823         VMSTATE_UINT32(vapic_size, GuestROMState),
824         VMSTATE_UINT32(vcpu_shift, GuestROMState),
825         VMSTATE_UINT32(real_tpr_addr, GuestROMState),
826         VMSTATE_STRUCT(up, GuestROMState, 0, vmstate_handlers, VAPICHandlers),
827         VMSTATE_STRUCT(mp, GuestROMState, 0, vmstate_handlers, VAPICHandlers),
828         VMSTATE_END_OF_LIST()
829     }
830 };
831 
832 static const VMStateDescription vmstate_vapic = {
833     .name = "kvm-tpr-opt",      /* compatible with qemu-kvm VAPIC */
834     .version_id = 1,
835     .minimum_version_id = 1,
836     .post_load = vapic_post_load,
837     .fields = (const VMStateField[]) {
838         VMSTATE_STRUCT(rom_state, VAPICROMState, 0, vmstate_guest_rom,
839                        GuestROMState),
840         VMSTATE_UINT32(state, VAPICROMState),
841         VMSTATE_UINT32(real_tpr_addr, VAPICROMState),
842         VMSTATE_UINT32(rom_state_vaddr, VAPICROMState),
843         VMSTATE_UINT32(vapic_paddr, VAPICROMState),
844         VMSTATE_UINT32(rom_state_paddr, VAPICROMState),
845         VMSTATE_END_OF_LIST()
846     }
847 };
848 
849 static void vapic_class_init(ObjectClass *klass, void *data)
850 {
851     DeviceClass *dc = DEVICE_CLASS(klass);
852 
853     dc->reset   = vapic_reset;
854     dc->vmsd    = &vmstate_vapic;
855     dc->realize = vapic_realize;
856 }
857 
858 static const TypeInfo vapic_type = {
859     .name          = TYPE_VAPIC,
860     .parent        = TYPE_SYS_BUS_DEVICE,
861     .instance_size = sizeof(VAPICROMState),
862     .class_init    = vapic_class_init,
863 };
864 
865 static void vapic_register(void)
866 {
867     type_register_static(&vapic_type);
868 }
869 
870 type_init(vapic_register);
871