Archipelago » qemu

/*

 * QEMU KVM support

 *

 * Copyright (C) 2006-2008 Qumranet Technologies

 * Copyright IBM, Corp. 2008

 *

 * Authors:

 *  Anthony Liguori   <aliguori@us.ibm.com>

 *

 * This work is licensed under the terms of the GNU GPL, version 2 or later.

 * See the COPYING file in the top-level directory.

 *

 */

#include <sys/types.h>

#include <sys/ioctl.h>

#include <sys/mman.h>

#include <linux/kvm.h>

#include "qemu-common.h"

#include "sysemu.h"

#include "kvm.h"

#include "cpu.h"

#include "gdbstub.h"

//#define DEBUG_KVM

#ifdef DEBUG_KVM

#define dprintf(fmt, ...) \

    do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)

#else

#define dprintf(fmt, ...) \

    do { } while (0)

#endif

int kvm_arch_init_vcpu(CPUState *env)

{

    struct {

        struct kvm_cpuid2 cpuid;

        struct kvm_cpuid_entry2 entries[100];

    } __attribute__((packed)) cpuid_data;

    uint32_t limit, i, j, cpuid_i;

    uint32_t eax, ebx, ecx, edx;

    cpuid_i = 0;

    cpu_x86_cpuid(env, 0, 0, &eax, &ebx, &ecx, &edx);

    limit = eax;

    for (i = 0; i <= limit; i++) {

        struct kvm_cpuid_entry2 *c = &cpuid_data.entries[cpuid_i++];

        switch (i) {

        case 2: {

            /* Keep reading function 2 till all the input is received */

            int times;

            cpu_x86_cpuid(env, i, 0, &eax, &ebx, &ecx, &edx);

            times = eax & 0xff;

            c->function = i;

            c->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;

            c->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;

            c->eax = eax;

            c->ebx = ebx;

            c->ecx = ecx;

            c->edx = edx;

            for (j = 1; j < times; ++j) {

                cpu_x86_cpuid(env, i, 0, &eax, &ebx, &ecx, &edx);

                c->function = i;

                c->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;

                c->eax = eax;

                c->ebx = ebx;

                c->ecx = ecx;

                c->edx = edx;

                c = &cpuid_data.entries[++cpuid_i];

            }

            break;

        }

        case 4:

        case 0xb:

        case 0xd:

            for (j = 0; ; j++) {

                cpu_x86_cpuid(env, i, j, &eax, &ebx, &ecx, &edx);

                c->function = i;

                c->flags = KVM_CPUID_FLAG_SIGNIFCANT_INDEX;

                c->index = j;

                c->eax = eax;

                c->ebx = ebx;

                c->ecx = ecx;

                c->edx = edx;

                c = &cpuid_data.entries[++cpuid_i];

                if (i == 4 && eax == 0)

                    break;

                if (i == 0xb && !(ecx & 0xff00))

                    break;

                if (i == 0xd && eax == 0)

                    break;

            }

            break;

        default:

            cpu_x86_cpuid(env, i, 0, &eax, &ebx, &ecx, &edx);

            c->function = i;

            c->eax = eax;

            c->ebx = ebx;

            c->ecx = ecx;

            c->edx = edx;

            break;

        }

    }

    cpu_x86_cpuid(env, 0x80000000, 0, &eax, &ebx, &ecx, &edx);

    limit = eax;

    for (i = 0x80000000; i <= limit; i++) {

        struct kvm_cpuid_entry2 *c = &cpuid_data.entries[cpuid_i++];

        cpu_x86_cpuid(env, i, 0, &eax, &ebx, &ecx, &edx);

        c->function = i;

        c->eax = eax;

        c->ebx = ebx;

        c->ecx = ecx;

        c->edx = edx;

    }

    cpuid_data.cpuid.nent = cpuid_i;

    return kvm_vcpu_ioctl(env, KVM_SET_CPUID2, &cpuid_data);

}

static int kvm_has_msr_star(CPUState *env)

{

    static int has_msr_star;

    int ret;

    /* first time */

    if (has_msr_star == 0) {        

        struct kvm_msr_list msr_list, *kvm_msr_list;

        has_msr_star = -1;

        /* Obtain MSR list from KVM.  These are the MSRs that we must

         * save/restore */

        msr_list.nmsrs = 0;

        ret = kvm_ioctl(env->kvm_state, KVM_GET_MSR_INDEX_LIST, &msr_list);

        if (ret < 0)

            return 0;

        kvm_msr_list = qemu_mallocz(sizeof(msr_list) +

                                    msr_list.nmsrs * sizeof(msr_list.indices[0]));

        kvm_msr_list->nmsrs = msr_list.nmsrs;

        ret = kvm_ioctl(env->kvm_state, KVM_GET_MSR_INDEX_LIST, kvm_msr_list);

        if (ret >= 0) {

            int i;

            for (i = 0; i < kvm_msr_list->nmsrs; i++) {

                if (kvm_msr_list->indices[i] == MSR_STAR) {

                    has_msr_star = 1;

                    break;

                }

            }

        }

        free(kvm_msr_list);

    }

    if (has_msr_star == 1)

        return 1;

    return 0;

}

int kvm_arch_init(KVMState *s, int smp_cpus)

{

    int ret;

    /* create vm86 tss.  KVM uses vm86 mode to emulate 16-bit code

     * directly.  In order to use vm86 mode, a TSS is needed.  Since this

     * must be part of guest physical memory, we need to allocate it.  Older

     * versions of KVM just assumed that it would be at the end of physical

     * memory but that doesn't work with more than 4GB of memory.  We simply

     * refuse to work with those older versions of KVM. */

    ret = kvm_ioctl(s, KVM_CHECK_EXTENSION, KVM_CAP_SET_TSS_ADDR);

    if (ret <= 0) {

        fprintf(stderr, "kvm does not support KVM_CAP_SET_TSS_ADDR\n");

        return ret;

    }

    /* this address is 3 pages before the bios, and the bios should present

     * as unavaible memory.  FIXME, need to ensure the e820 map deals with

     * this?

     */

    return kvm_vm_ioctl(s, KVM_SET_TSS_ADDR, 0xfffbd000);

}

static void set_v8086_seg(struct kvm_segment *lhs, const SegmentCache *rhs)

{

    lhs->selector = rhs->selector;

    lhs->base = rhs->base;

    lhs->limit = rhs->limit;

    lhs->type = 3;

    lhs->present = 1;

    lhs->dpl = 3;

    lhs->db = 0;

    lhs->s = 1;

    lhs->l = 0;

    lhs->g = 0;

    lhs->avl = 0;

    lhs->unusable = 0;

}

static void set_seg(struct kvm_segment *lhs, const SegmentCache *rhs)

{

    unsigned flags = rhs->flags;

    lhs->selector = rhs->selector;

    lhs->base = rhs->base;

    lhs->limit = rhs->limit;

    lhs->type = (flags >> DESC_TYPE_SHIFT) & 15;

    lhs->present = (flags & DESC_P_MASK) != 0;

    lhs->dpl = rhs->selector & 3;

    lhs->db = (flags >> DESC_B_SHIFT) & 1;

    lhs->s = (flags & DESC_S_MASK) != 0;

    lhs->l = (flags >> DESC_L_SHIFT) & 1;

    lhs->g = (flags & DESC_G_MASK) != 0;

    lhs->avl = (flags & DESC_AVL_MASK) != 0;

    lhs->unusable = 0;

}

static void get_seg(SegmentCache *lhs, const struct kvm_segment *rhs)

{

    lhs->selector = rhs->selector;

    lhs->base = rhs->base;

    lhs->limit = rhs->limit;

    lhs->flags =

        (rhs->type << DESC_TYPE_SHIFT)

        | (rhs->present * DESC_P_MASK)

        | (rhs->dpl << DESC_DPL_SHIFT)

        | (rhs->db << DESC_B_SHIFT)

        | (rhs->s * DESC_S_MASK)

        | (rhs->l << DESC_L_SHIFT)

        | (rhs->g * DESC_G_MASK)

        | (rhs->avl * DESC_AVL_MASK);

}

static void kvm_getput_reg(__u64 *kvm_reg, target_ulong *qemu_reg, int set)

{

    if (set)

        *kvm_reg = *qemu_reg;

    else

        *qemu_reg = *kvm_reg;

}

static int kvm_getput_regs(CPUState *env, int set)

{

    struct kvm_regs regs;

    int ret = 0;

    if (!set) {

        ret = kvm_vcpu_ioctl(env, KVM_GET_REGS, &regs);

        if (ret < 0)

            return ret;

    }

    kvm_getput_reg(&regs.rax, &env->regs[R_EAX], set);

    kvm_getput_reg(&regs.rbx, &env->regs[R_EBX], set);

    kvm_getput_reg(&regs.rcx, &env->regs[R_ECX], set);

    kvm_getput_reg(&regs.rdx, &env->regs[R_EDX], set);

    kvm_getput_reg(&regs.rsi, &env->regs[R_ESI], set);

    kvm_getput_reg(&regs.rdi, &env->regs[R_EDI], set);

    kvm_getput_reg(&regs.rsp, &env->regs[R_ESP], set);

    kvm_getput_reg(&regs.rbp, &env->regs[R_EBP], set);

#ifdef TARGET_X86_64

    kvm_getput_reg(&regs.r8, &env->regs[8], set);

    kvm_getput_reg(&regs.r9, &env->regs[9], set);

    kvm_getput_reg(&regs.r10, &env->regs[10], set);

    kvm_getput_reg(&regs.r11, &env->regs[11], set);

    kvm_getput_reg(&regs.r12, &env->regs[12], set);

    kvm_getput_reg(&regs.r13, &env->regs[13], set);

    kvm_getput_reg(&regs.r14, &env->regs[14], set);

    kvm_getput_reg(&regs.r15, &env->regs[15], set);

#endif

    kvm_getput_reg(&regs.rflags, &env->eflags, set);

    kvm_getput_reg(&regs.rip, &env->eip, set);

    if (set)

        ret = kvm_vcpu_ioctl(env, KVM_SET_REGS, &regs);

    return ret;

}

static int kvm_put_fpu(CPUState *env)

{

    struct kvm_fpu fpu;

    int i;

    memset(&fpu, 0, sizeof fpu);

    fpu.fsw = env->fpus & ~(7 << 11);

    fpu.fsw |= (env->fpstt & 7) << 11;

    fpu.fcw = env->fpuc;

    for (i = 0; i < 8; ++i)

        fpu.ftwx |= (!env->fptags[i]) << i;

    memcpy(fpu.fpr, env->fpregs, sizeof env->fpregs);

    memcpy(fpu.xmm, env->xmm_regs, sizeof env->xmm_regs);

    fpu.mxcsr = env->mxcsr;

    return kvm_vcpu_ioctl(env, KVM_SET_FPU, &fpu);

}

static int kvm_put_sregs(CPUState *env)

{

    struct kvm_sregs sregs;

    memcpy(sregs.interrupt_bitmap,

           env->interrupt_bitmap,

           sizeof(sregs.interrupt_bitmap));

    if ((env->eflags & VM_MASK)) {

            set_v8086_seg(&sregs.cs, &env->segs[R_CS]);

            set_v8086_seg(&sregs.ds, &env->segs[R_DS]);

            set_v8086_seg(&sregs.es, &env->segs[R_ES]);

            set_v8086_seg(&sregs.fs, &env->segs[R_FS]);

            set_v8086_seg(&sregs.gs, &env->segs[R_GS]);

            set_v8086_seg(&sregs.ss, &env->segs[R_SS]);

    } else {

            set_seg(&sregs.cs, &env->segs[R_CS]);

            set_seg(&sregs.ds, &env->segs[R_DS]);

            set_seg(&sregs.es, &env->segs[R_ES]);

            set_seg(&sregs.fs, &env->segs[R_FS]);

            set_seg(&sregs.gs, &env->segs[R_GS]);

            set_seg(&sregs.ss, &env->segs[R_SS]);

            if (env->cr[0] & CR0_PE_MASK) {

                /* force ss cpl to cs cpl */

                sregs.ss.selector = (sregs.ss.selector & ~3) |

                        (sregs.cs.selector & 3);

                sregs.ss.dpl = sregs.ss.selector & 3;

            }

    }

    set_seg(&sregs.tr, &env->tr);

    set_seg(&sregs.ldt, &env->ldt);

    sregs.idt.limit = env->idt.limit;

    sregs.idt.base = env->idt.base;

    sregs.gdt.limit = env->gdt.limit;

    sregs.gdt.base = env->gdt.base;

    sregs.cr0 = env->cr[0];

    sregs.cr2 = env->cr[2];

    sregs.cr3 = env->cr[3];

    sregs.cr4 = env->cr[4];

    sregs.cr8 = cpu_get_apic_tpr(env);

    sregs.apic_base = cpu_get_apic_base(env);

    sregs.efer = env->efer;

    return kvm_vcpu_ioctl(env, KVM_SET_SREGS, &sregs);

}

static void kvm_msr_entry_set(struct kvm_msr_entry *entry,

                              uint32_t index, uint64_t value)

{

    entry->index = index;

    entry->data = value;

}

static int kvm_put_msrs(CPUState *env)

{

    struct {

        struct kvm_msrs info;

        struct kvm_msr_entry entries[100];

    } msr_data;

    struct kvm_msr_entry *msrs = msr_data.entries;

    int n = 0;

    kvm_msr_entry_set(&msrs[n++], MSR_IA32_SYSENTER_CS, env->sysenter_cs);

    kvm_msr_entry_set(&msrs[n++], MSR_IA32_SYSENTER_ESP, env->sysenter_esp);

    kvm_msr_entry_set(&msrs[n++], MSR_IA32_SYSENTER_EIP, env->sysenter_eip);

    if (kvm_has_msr_star(env))

        kvm_msr_entry_set(&msrs[n++], MSR_STAR, env->star);

    kvm_msr_entry_set(&msrs[n++], MSR_IA32_TSC, env->tsc);

#ifdef TARGET_X86_64

    /* FIXME if lm capable */

    kvm_msr_entry_set(&msrs[n++], MSR_CSTAR, env->cstar);

    kvm_msr_entry_set(&msrs[n++], MSR_KERNELGSBASE, env->kernelgsbase);

    kvm_msr_entry_set(&msrs[n++], MSR_FMASK, env->fmask);

    kvm_msr_entry_set(&msrs[n++], MSR_LSTAR, env->lstar);

#endif

    msr_data.info.nmsrs = n;

    return kvm_vcpu_ioctl(env, KVM_SET_MSRS, &msr_data);

}

static int kvm_get_fpu(CPUState *env)

{

    struct kvm_fpu fpu;

    int i, ret;

    ret = kvm_vcpu_ioctl(env, KVM_GET_FPU, &fpu);

    if (ret < 0)

        return ret;

    env->fpstt = (fpu.fsw >> 11) & 7;

    env->fpus = fpu.fsw;

    env->fpuc = fpu.fcw;

    for (i = 0; i < 8; ++i)

        env->fptags[i] = !((fpu.ftwx >> i) & 1);

    memcpy(env->fpregs, fpu.fpr, sizeof env->fpregs);

    memcpy(env->xmm_regs, fpu.xmm, sizeof env->xmm_regs);

    env->mxcsr = fpu.mxcsr;

    return 0;

}

static int kvm_get_sregs(CPUState *env)

{

    struct kvm_sregs sregs;

    uint32_t hflags;

    int ret;

    ret = kvm_vcpu_ioctl(env, KVM_GET_SREGS, &sregs);

    if (ret < 0)

        return ret;

    memcpy(env->interrupt_bitmap, 

           sregs.interrupt_bitmap,

           sizeof(sregs.interrupt_bitmap));

    get_seg(&env->segs[R_CS], &sregs.cs);

    get_seg(&env->segs[R_DS], &sregs.ds);

    get_seg(&env->segs[R_ES], &sregs.es);

    get_seg(&env->segs[R_FS], &sregs.fs);

    get_seg(&env->segs[R_GS], &sregs.gs);

    get_seg(&env->segs[R_SS], &sregs.ss);

    get_seg(&env->tr, &sregs.tr);

    get_seg(&env->ldt, &sregs.ldt);

    env->idt.limit = sregs.idt.limit;

    env->idt.base = sregs.idt.base;

    env->gdt.limit = sregs.gdt.limit;

    env->gdt.base = sregs.gdt.base;

    env->cr[0] = sregs.cr0;

    env->cr[2] = sregs.cr2;

    env->cr[3] = sregs.cr3;

    env->cr[4] = sregs.cr4;

    cpu_set_apic_base(env, sregs.apic_base);

    env->efer = sregs.efer;

    //cpu_set_apic_tpr(env, sregs.cr8);

#define HFLAG_COPY_MASK ~( \

                        HF_CPL_MASK | HF_PE_MASK | HF_MP_MASK | HF_EM_MASK | \

                        HF_TS_MASK | HF_TF_MASK | HF_VM_MASK | HF_IOPL_MASK | \

                        HF_OSFXSR_MASK | HF_LMA_MASK | HF_CS32_MASK | \

                        HF_SS32_MASK | HF_CS64_MASK | HF_ADDSEG_MASK)

    hflags = (env->segs[R_CS].flags >> DESC_DPL_SHIFT) & HF_CPL_MASK;

    hflags |= (env->cr[0] & CR0_PE_MASK) << (HF_PE_SHIFT - CR0_PE_SHIFT);

    hflags |= (env->cr[0] << (HF_MP_SHIFT - CR0_MP_SHIFT)) &

            (HF_MP_MASK | HF_EM_MASK | HF_TS_MASK);

    hflags |= (env->eflags & (HF_TF_MASK | HF_VM_MASK | HF_IOPL_MASK));

    hflags |= (env->cr[4] & CR4_OSFXSR_MASK) <<

            (HF_OSFXSR_SHIFT - CR4_OSFXSR_SHIFT);

    if (env->efer & MSR_EFER_LMA) {

        hflags |= HF_LMA_MASK;

    }

    if ((hflags & HF_LMA_MASK) && (env->segs[R_CS].flags & DESC_L_MASK)) {

        hflags |= HF_CS32_MASK | HF_SS32_MASK | HF_CS64_MASK;

    } else {

        hflags |= (env->segs[R_CS].flags & DESC_B_MASK) >>

                (DESC_B_SHIFT - HF_CS32_SHIFT);

        hflags |= (env->segs[R_SS].flags & DESC_B_MASK) >>

                (DESC_B_SHIFT - HF_SS32_SHIFT);

        if (!(env->cr[0] & CR0_PE_MASK) ||

                   (env->eflags & VM_MASK) ||

                   !(hflags & HF_CS32_MASK)) {

                hflags |= HF_ADDSEG_MASK;

            } else {

                hflags |= ((env->segs[R_DS].base |

                                env->segs[R_ES].base |

                                env->segs[R_SS].base) != 0) <<

                    HF_ADDSEG_SHIFT;

            }

    }

    env->hflags = (env->hflags & HFLAG_COPY_MASK) | hflags;

    return 0;

}

static int kvm_get_msrs(CPUState *env)

{

    struct {

        struct kvm_msrs info;

        struct kvm_msr_entry entries[100];

    } msr_data;

    struct kvm_msr_entry *msrs = msr_data.entries;

    int ret, i, n;

    n = 0;

    msrs[n++].index = MSR_IA32_SYSENTER_CS;

    msrs[n++].index = MSR_IA32_SYSENTER_ESP;

    msrs[n++].index = MSR_IA32_SYSENTER_EIP;

    if (kvm_has_msr_star(env))

        msrs[n++].index = MSR_STAR;

    msrs[n++].index = MSR_IA32_TSC;

#ifdef TARGET_X86_64

    /* FIXME lm_capable_kernel */

    msrs[n++].index = MSR_CSTAR;

    msrs[n++].index = MSR_KERNELGSBASE;

    msrs[n++].index = MSR_FMASK;

    msrs[n++].index = MSR_LSTAR;

#endif

    msr_data.info.nmsrs = n;

    ret = kvm_vcpu_ioctl(env, KVM_GET_MSRS, &msr_data);

    if (ret < 0)

        return ret;

    for (i = 0; i < ret; i++) {

        switch (msrs[i].index) {

        case MSR_IA32_SYSENTER_CS:

            env->sysenter_cs = msrs[i].data;

            break;

        case MSR_IA32_SYSENTER_ESP:

            env->sysenter_esp = msrs[i].data;

            break;

        case MSR_IA32_SYSENTER_EIP:

            env->sysenter_eip = msrs[i].data;

            break;

        case MSR_STAR:

            env->star = msrs[i].data;

            break;

#ifdef TARGET_X86_64

        case MSR_CSTAR:

            env->cstar = msrs[i].data;

            break;

        case MSR_KERNELGSBASE:

            env->kernelgsbase = msrs[i].data;

            break;

        case MSR_FMASK:

            env->fmask = msrs[i].data;

            break;

        case MSR_LSTAR:

            env->lstar = msrs[i].data;

            break;

#endif

        case MSR_IA32_TSC:

            env->tsc = msrs[i].data;

            break;

        }

    }

    return 0;

}

int kvm_arch_put_registers(CPUState *env)

{

    int ret;

    ret = kvm_getput_regs(env, 1);

    if (ret < 0)

        return ret;

    ret = kvm_put_fpu(env);

    if (ret < 0)

        return ret;

    ret = kvm_put_sregs(env);

    if (ret < 0)

        return ret;

    ret = kvm_put_msrs(env);

    if (ret < 0)

        return ret;

    return 0;

}

int kvm_arch_get_registers(CPUState *env)

{

    int ret;

    ret = kvm_getput_regs(env, 0);

    if (ret < 0)

        return ret;

    ret = kvm_get_fpu(env);

    if (ret < 0)

        return ret;

    ret = kvm_get_sregs(env);

    if (ret < 0)

        return ret;

    ret = kvm_get_msrs(env);

    if (ret < 0)

        return ret;

    return 0;

}

int kvm_arch_pre_run(CPUState *env, struct kvm_run *run)

{

    /* Try to inject an interrupt if the guest can accept it */

    if (run->ready_for_interrupt_injection &&

        (env->interrupt_request & CPU_INTERRUPT_HARD) &&

        (env->eflags & IF_MASK)) {

        int irq;

        env->interrupt_request &= ~CPU_INTERRUPT_HARD;

        irq = cpu_get_pic_interrupt(env);

        if (irq >= 0) {

            struct kvm_interrupt intr;

            intr.irq = irq;

            /* FIXME: errors */

            dprintf("injected interrupt %d\n", irq);

            kvm_vcpu_ioctl(env, KVM_INTERRUPT, &intr);

        }

    }

    /* If we have an interrupt but the guest is not ready to receive an

     * interrupt, request an interrupt window exit.  This will

     * cause a return to userspace as soon as the guest is ready to

     * receive interrupts. */

    if ((env->interrupt_request & CPU_INTERRUPT_HARD))

        run->request_interrupt_window = 1;

    else

        run->request_interrupt_window = 0;

    dprintf("setting tpr\n");

    run->cr8 = cpu_get_apic_tpr(env);

    return 0;

}

int kvm_arch_post_run(CPUState *env, struct kvm_run *run)

{

    if (run->if_flag)

        env->eflags |= IF_MASK;

    else

        env->eflags &= ~IF_MASK;

    cpu_set_apic_tpr(env, run->cr8);

    cpu_set_apic_base(env, run->apic_base);

    return 0;

}

static int kvm_handle_halt(CPUState *env)

{

    if (!((env->interrupt_request & CPU_INTERRUPT_HARD) &&

          (env->eflags & IF_MASK)) &&

        !(env->interrupt_request & CPU_INTERRUPT_NMI)) {

        env->halted = 1;

        env->exception_index = EXCP_HLT;

        return 0;

    }

    return 1;

}

int kvm_arch_handle_exit(CPUState *env, struct kvm_run *run)

{

    int ret = 0;

    switch (run->exit_reason) {

    case KVM_EXIT_HLT:

        dprintf("handle_hlt\n");

        ret = kvm_handle_halt(env);

        break;

    }

    return ret;

}

#ifdef KVM_CAP_SET_GUEST_DEBUG

int kvm_arch_insert_sw_breakpoint(CPUState *env, struct kvm_sw_breakpoint *bp)

{

    const static uint8_t int3 = 0xcc;

    if (cpu_memory_rw_debug(env, bp->pc, (uint8_t *)&bp->saved_insn, 1, 0) ||

        cpu_memory_rw_debug(env, bp->pc, (uint8_t *)&int3, 1, 1))

        return -EINVAL;

    return 0;

}

int kvm_arch_remove_sw_breakpoint(CPUState *env, struct kvm_sw_breakpoint *bp)

{

    uint8_t int3;

    if (cpu_memory_rw_debug(env, bp->pc, &int3, 1, 0) || int3 != 0xcc ||

        cpu_memory_rw_debug(env, bp->pc, (uint8_t *)&bp->saved_insn, 1, 1))

        return -EINVAL;

    return 0;

}

static struct {

    target_ulong addr;

    int len;

    int type;

} hw_breakpoint[4];

static int nb_hw_breakpoint;

static int find_hw_breakpoint(target_ulong addr, int len, int type)

{

    int n;

    for (n = 0; n < nb_hw_breakpoint; n++)

        if (hw_breakpoint[n].addr == addr && hw_breakpoint[n].type == type &&

            (hw_breakpoint[n].len == len || len == -1))

            return n;

    return -1;

}

int kvm_arch_insert_hw_breakpoint(target_ulong addr,

                                  target_ulong len, int type)

{

    switch (type) {

    case GDB_BREAKPOINT_HW:

        len = 1;

        break;

    case GDB_WATCHPOINT_WRITE:

    case GDB_WATCHPOINT_ACCESS:

        switch (len) {

        case 1:

            break;

        case 2:

        case 4:

        case 8:

            if (addr & (len - 1))

                return -EINVAL;

            break;

        default:

            return -EINVAL;

        }

        break;

    default:

        return -ENOSYS;

    }

    if (nb_hw_breakpoint == 4)

        return -ENOBUFS;

    if (find_hw_breakpoint(addr, len, type) >= 0)

        return -EEXIST;

    hw_breakpoint[nb_hw_breakpoint].addr = addr;

    hw_breakpoint[nb_hw_breakpoint].len = len;

    hw_breakpoint[nb_hw_breakpoint].type = type;

    nb_hw_breakpoint++;

    return 0;

}

int kvm_arch_remove_hw_breakpoint(target_ulong addr,

                                  target_ulong len, int type)

{

    int n;

    n = find_hw_breakpoint(addr, (type == GDB_BREAKPOINT_HW) ? 1 : len, type);

    if (n < 0)

        return -ENOENT;

    nb_hw_breakpoint--;

    hw_breakpoint[n] = hw_breakpoint[nb_hw_breakpoint];

    return 0;

}

void kvm_arch_remove_all_hw_breakpoints(void)

{

    nb_hw_breakpoint = 0;

}

static CPUWatchpoint hw_watchpoint;

int kvm_arch_debug(struct kvm_debug_exit_arch *arch_info)

{

    int handle = 0;

    int n;

    if (arch_info->exception == 1) {

        if (arch_info->dr6 & (1 << 14)) {

            if (cpu_single_env->singlestep_enabled)

                handle = 1;

        } else {

            for (n = 0; n < 4; n++)

                if (arch_info->dr6 & (1 << n))

                    switch ((arch_info->dr7 >> (16 + n*4)) & 0x3) {

                    case 0x0:

                        handle = 1;

                        break;

                    case 0x1:

                        handle = 1;

                        cpu_single_env->watchpoint_hit = &hw_watchpoint;

                        hw_watchpoint.vaddr = hw_breakpoint[n].addr;

                        hw_watchpoint.flags = BP_MEM_WRITE;

                        break;

                    case 0x3:

                        handle = 1;

                        cpu_single_env->watchpoint_hit = &hw_watchpoint;

                        hw_watchpoint.vaddr = hw_breakpoint[n].addr;

                        hw_watchpoint.flags = BP_MEM_ACCESS;

                        break;

                    }

        }

    } else if (kvm_find_sw_breakpoint(cpu_single_env, arch_info->pc))

        handle = 1;

    if (!handle)

        kvm_update_guest_debug(cpu_single_env,

                        (arch_info->exception == 1) ?

                        KVM_GUESTDBG_INJECT_DB : KVM_GUESTDBG_INJECT_BP);

    return handle;

}

void kvm_arch_update_guest_debug(CPUState *env, struct kvm_guest_debug *dbg)

{

    const uint8_t type_code[] = {

        [GDB_BREAKPOINT_HW] = 0x0,

        [GDB_WATCHPOINT_WRITE] = 0x1,

        [GDB_WATCHPOINT_ACCESS] = 0x3

    };

    const uint8_t len_code[] = {

        [1] = 0x0, [2] = 0x1, [4] = 0x3, [8] = 0x2

    };

    int n;

    if (kvm_sw_breakpoints_active(env))

        dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP;

    if (nb_hw_breakpoint > 0) {

        dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;

        dbg->arch.debugreg[7] = 0x0600;

        for (n = 0; n < nb_hw_breakpoint; n++) {

            dbg->arch.debugreg[n] = hw_breakpoint[n].addr;

            dbg->arch.debugreg[7] |= (2 << (n * 2)) |

                (type_code[hw_breakpoint[n].type] << (16 + n*4)) |

                (len_code[hw_breakpoint[n].len] << (18 + n*4));

        }

    }

}

#endif /* KVM_CAP_SET_GUEST_DEBUG */