Archipelago » qemu

/*

 * ARM implementation of KVM hooks, 32 bit specific code.

 *

 * Copyright Christoffer Dall 2009-2010

 *

 * 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 <stdio.h>

#include <sys/types.h>

#include <sys/ioctl.h>

#include <sys/mman.h>

#include <linux/kvm.h>

#include "qemu-common.h"

#include "qemu/timer.h"

#include "sysemu/sysemu.h"

#include "sysemu/kvm.h"

#include "kvm_arm.h"

#include "cpu.h"

#include "hw/arm/arm.h"

static inline void set_feature(uint64_t *features, int feature)

{

    *features |= 1ULL << feature;

}

bool kvm_arm_get_host_cpu_features(ARMHostCPUClass *ahcc)

{

    /* Identify the feature bits corresponding to the host CPU, and

     * fill out the ARMHostCPUClass fields accordingly. To do this

     * we have to create a scratch VM, create a single CPU inside it,

     * and then query that CPU for the relevant ID registers.

     */

    int i, ret, fdarray[3];

    uint32_t midr, id_pfr0, id_isar0, mvfr1;

    uint64_t features = 0;

    /* Old kernels may not know about the PREFERRED_TARGET ioctl: however

     * we know these will only support creating one kind of guest CPU,

     * which is its preferred CPU type.

     */

    static const uint32_t cpus_to_try[] = {

        QEMU_KVM_ARM_TARGET_CORTEX_A15,

        QEMU_KVM_ARM_TARGET_NONE

    };

    struct kvm_vcpu_init init;

    struct kvm_one_reg idregs[] = {

        {

            .id = KVM_REG_ARM | KVM_REG_SIZE_U32

            | ENCODE_CP_REG(15, 0, 0, 0, 0, 0),

            .addr = (uintptr_t)&midr,

        },

        {

            .id = KVM_REG_ARM | KVM_REG_SIZE_U32

            | ENCODE_CP_REG(15, 0, 0, 1, 0, 0),

            .addr = (uintptr_t)&id_pfr0,

        },

        {

            .id = KVM_REG_ARM | KVM_REG_SIZE_U32

            | ENCODE_CP_REG(15, 0, 0, 2, 0, 0),

            .addr = (uintptr_t)&id_isar0,

        },

        {

            .id = KVM_REG_ARM | KVM_REG_SIZE_U32

            | KVM_REG_ARM_VFP | KVM_REG_ARM_VFP_MVFR1,

            .addr = (uintptr_t)&mvfr1,

        },

    };

    if (!kvm_arm_create_scratch_host_vcpu(cpus_to_try, fdarray, &init)) {

        return false;

    }

    ahcc->target = init.target;

    /* This is not strictly blessed by the device tree binding docs yet,

     * but in practice the kernel does not care about this string so

     * there is no point maintaining an KVM_ARM_TARGET_* -> string table.

     */

    ahcc->dtb_compatible = "arm,arm-v7";

    for (i = 0; i < ARRAY_SIZE(idregs); i++) {

        ret = ioctl(fdarray[2], KVM_GET_ONE_REG, &idregs[i]);

        if (ret) {

            break;

        }

    }

    kvm_arm_destroy_scratch_host_vcpu(fdarray);

    if (ret) {

        return false;

    }

    /* Now we've retrieved all the register information we can

     * set the feature bits based on the ID register fields.

     * We can assume any KVM supporting CPU is at least a v7

     * with VFPv3, LPAE and the generic timers; this in turn implies

     * most of the other feature bits, but a few must be tested.

     */

    set_feature(&features, ARM_FEATURE_V7);

    set_feature(&features, ARM_FEATURE_VFP3);

    set_feature(&features, ARM_FEATURE_LPAE);

    set_feature(&features, ARM_FEATURE_GENERIC_TIMER);

    switch (extract32(id_isar0, 24, 4)) {

    case 1:

        set_feature(&features, ARM_FEATURE_THUMB_DIV);

        break;

    case 2:

        set_feature(&features, ARM_FEATURE_ARM_DIV);

        set_feature(&features, ARM_FEATURE_THUMB_DIV);

        break;

    default:

        break;

    }

    if (extract32(id_pfr0, 12, 4) == 1) {

        set_feature(&features, ARM_FEATURE_THUMB2EE);

    }

    if (extract32(mvfr1, 20, 4) == 1) {

        set_feature(&features, ARM_FEATURE_VFP_FP16);

    }

    if (extract32(mvfr1, 12, 4) == 1) {

        set_feature(&features, ARM_FEATURE_NEON);

    }

    if (extract32(mvfr1, 28, 4) == 1) {

        /* FMAC support implies VFPv4 */

        set_feature(&features, ARM_FEATURE_VFP4);

    }

    ahcc->features = features;

    return true;

}

static bool reg_syncs_via_tuple_list(uint64_t regidx)

{

    /* Return true if the regidx is a register we should synchronize

     * via the cpreg_tuples array (ie is not a core reg we sync by

     * hand in kvm_arch_get/put_registers())

     */

    switch (regidx & KVM_REG_ARM_COPROC_MASK) {

    case KVM_REG_ARM_CORE:

    case KVM_REG_ARM_VFP:

        return false;

    default:

        return true;

    }

}

static int compare_u64(const void *a, const void *b)

{

    if (*(uint64_t *)a > *(uint64_t *)b) {

        return 1;

    }

    if (*(uint64_t *)a < *(uint64_t *)b) {

        return -1;

    }

    return 0;

}

int kvm_arch_init_vcpu(CPUState *cs)

{

    struct kvm_vcpu_init init;

    int i, ret, arraylen;

    uint64_t v;

    struct kvm_one_reg r;

    struct kvm_reg_list rl;

    struct kvm_reg_list *rlp;

    ARMCPU *cpu = ARM_CPU(cs);

    if (cpu->kvm_target == QEMU_KVM_ARM_TARGET_NONE) {

        fprintf(stderr, "KVM is not supported for this guest CPU type\n");

        return -EINVAL;

    }

    init.target = cpu->kvm_target;

    memset(init.features, 0, sizeof(init.features));

    if (cpu->start_powered_off) {

        init.features[0] = 1 << KVM_ARM_VCPU_POWER_OFF;

    }

    ret = kvm_vcpu_ioctl(cs, KVM_ARM_VCPU_INIT, &init);

    if (ret) {

        return ret;

    }

    /* Query the kernel to make sure it supports 32 VFP

     * registers: QEMU's "cortex-a15" CPU is always a

     * VFP-D32 core. The simplest way to do this is just

     * to attempt to read register d31.

     */

    r.id = KVM_REG_ARM | KVM_REG_SIZE_U64 | KVM_REG_ARM_VFP | 31;

    r.addr = (uintptr_t)(&v);

    ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &r);

    if (ret == -ENOENT) {

        return -EINVAL;

    }

    /* Populate the cpreg list based on the kernel's idea

     * of what registers exist (and throw away the TCG-created list).

     */

    rl.n = 0;

    ret = kvm_vcpu_ioctl(cs, KVM_GET_REG_LIST, &rl);

    if (ret != -E2BIG) {

        return ret;

    }

    rlp = g_malloc(sizeof(struct kvm_reg_list) + rl.n * sizeof(uint64_t));

    rlp->n = rl.n;

    ret = kvm_vcpu_ioctl(cs, KVM_GET_REG_LIST, rlp);

    if (ret) {

        goto out;

    }

    /* Sort the list we get back from the kernel, since cpreg_tuples

     * must be in strictly ascending order.

     */

    qsort(&rlp->reg, rlp->n, sizeof(rlp->reg[0]), compare_u64);

    for (i = 0, arraylen = 0; i < rlp->n; i++) {

        if (!reg_syncs_via_tuple_list(rlp->reg[i])) {

            continue;

        }

        switch (rlp->reg[i] & KVM_REG_SIZE_MASK) {

        case KVM_REG_SIZE_U32:

        case KVM_REG_SIZE_U64:

            break;

        default:

            fprintf(stderr, "Can't handle size of register in kernel list\n");

            ret = -EINVAL;

            goto out;

        }

        arraylen++;

    }

    cpu->cpreg_indexes = g_renew(uint64_t, cpu->cpreg_indexes, arraylen);

    cpu->cpreg_values = g_renew(uint64_t, cpu->cpreg_values, arraylen);

    cpu->cpreg_vmstate_indexes = g_renew(uint64_t, cpu->cpreg_vmstate_indexes,

                                         arraylen);

    cpu->cpreg_vmstate_values = g_renew(uint64_t, cpu->cpreg_vmstate_values,

                                        arraylen);

    cpu->cpreg_array_len = arraylen;

    cpu->cpreg_vmstate_array_len = arraylen;

    for (i = 0, arraylen = 0; i < rlp->n; i++) {

        uint64_t regidx = rlp->reg[i];

        if (!reg_syncs_via_tuple_list(regidx)) {

            continue;

        }

        cpu->cpreg_indexes[arraylen] = regidx;

        arraylen++;

    }

    assert(cpu->cpreg_array_len == arraylen);

    if (!write_kvmstate_to_list(cpu)) {

        /* Shouldn't happen unless kernel is inconsistent about

         * what registers exist.

         */

        fprintf(stderr, "Initial read of kernel register state failed\n");

        ret = -EINVAL;

        goto out;

    }

    /* Save a copy of the initial register values so that we can

     * feed it back to the kernel on VCPU reset.

     */

    cpu->cpreg_reset_values = g_memdup(cpu->cpreg_values,

                                       cpu->cpreg_array_len *

                                       sizeof(cpu->cpreg_values[0]));

out:

    g_free(rlp);

    return ret;

}

typedef struct Reg {

    uint64_t id;

    int offset;

} Reg;

#define COREREG(KERNELNAME, QEMUFIELD)                       \

    {                                                        \

        KVM_REG_ARM | KVM_REG_SIZE_U32 |                     \

        KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(KERNELNAME), \

        offsetof(CPUARMState, QEMUFIELD)                     \

    }

#define VFPSYSREG(R)                                       \

    {                                                      \

        KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_VFP | \

        KVM_REG_ARM_VFP_##R,                               \

        offsetof(CPUARMState, vfp.xregs[ARM_VFP_##R])      \

    }

static const Reg regs[] = {

    /* R0_usr .. R14_usr */

    COREREG(usr_regs.uregs[0], regs[0]),

    COREREG(usr_regs.uregs[1], regs[1]),

    COREREG(usr_regs.uregs[2], regs[2]),

    COREREG(usr_regs.uregs[3], regs[3]),

    COREREG(usr_regs.uregs[4], regs[4]),

    COREREG(usr_regs.uregs[5], regs[5]),

    COREREG(usr_regs.uregs[6], regs[6]),

    COREREG(usr_regs.uregs[7], regs[7]),

    COREREG(usr_regs.uregs[8], usr_regs[0]),

    COREREG(usr_regs.uregs[9], usr_regs[1]),

    COREREG(usr_regs.uregs[10], usr_regs[2]),

    COREREG(usr_regs.uregs[11], usr_regs[3]),

    COREREG(usr_regs.uregs[12], usr_regs[4]),

    COREREG(usr_regs.uregs[13], banked_r13[0]),

    COREREG(usr_regs.uregs[14], banked_r14[0]),

    /* R13, R14, SPSR for SVC, ABT, UND, IRQ banks */

    COREREG(svc_regs[0], banked_r13[1]),

    COREREG(svc_regs[1], banked_r14[1]),

    COREREG(svc_regs[2], banked_spsr[1]),

    COREREG(abt_regs[0], banked_r13[2]),

    COREREG(abt_regs[1], banked_r14[2]),

    COREREG(abt_regs[2], banked_spsr[2]),

    COREREG(und_regs[0], banked_r13[3]),

    COREREG(und_regs[1], banked_r14[3]),

    COREREG(und_regs[2], banked_spsr[3]),

    COREREG(irq_regs[0], banked_r13[4]),

    COREREG(irq_regs[1], banked_r14[4]),

    COREREG(irq_regs[2], banked_spsr[4]),

    /* R8_fiq .. R14_fiq and SPSR_fiq */

    COREREG(fiq_regs[0], fiq_regs[0]),

    COREREG(fiq_regs[1], fiq_regs[1]),

    COREREG(fiq_regs[2], fiq_regs[2]),

    COREREG(fiq_regs[3], fiq_regs[3]),

    COREREG(fiq_regs[4], fiq_regs[4]),

    COREREG(fiq_regs[5], banked_r13[5]),

    COREREG(fiq_regs[6], banked_r14[5]),

    COREREG(fiq_regs[7], banked_spsr[5]),

    /* R15 */

    COREREG(usr_regs.uregs[15], regs[15]),

    /* VFP system registers */

    VFPSYSREG(FPSID),

    VFPSYSREG(MVFR1),

    VFPSYSREG(MVFR0),

    VFPSYSREG(FPEXC),

    VFPSYSREG(FPINST),

    VFPSYSREG(FPINST2),

};

int kvm_arch_put_registers(CPUState *cs, int level)

{

    ARMCPU *cpu = ARM_CPU(cs);

    CPUARMState *env = &cpu->env;

    struct kvm_one_reg r;

    int mode, bn;

    int ret, i;

    uint32_t cpsr, fpscr;

    /* Make sure the banked regs are properly set */

    mode = env->uncached_cpsr & CPSR_M;

    bn = bank_number(mode);

    if (mode == ARM_CPU_MODE_FIQ) {

        memcpy(env->fiq_regs, env->regs + 8, 5 * sizeof(uint32_t));

    } else {

        memcpy(env->usr_regs, env->regs + 8, 5 * sizeof(uint32_t));

    }

    env->banked_r13[bn] = env->regs[13];

    env->banked_r14[bn] = env->regs[14];

    env->banked_spsr[bn] = env->spsr;

    /* Now we can safely copy stuff down to the kernel */

    for (i = 0; i < ARRAY_SIZE(regs); i++) {

        r.id = regs[i].id;

        r.addr = (uintptr_t)(env) + regs[i].offset;

        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &r);

        if (ret) {

            return ret;

        }

    }

    /* Special cases which aren't a single CPUARMState field */

    cpsr = cpsr_read(env);

    r.id = KVM_REG_ARM | KVM_REG_SIZE_U32 |

        KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(usr_regs.ARM_cpsr);

    r.addr = (uintptr_t)(&cpsr);

    ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &r);

    if (ret) {

        return ret;

    }

    /* VFP registers */

    r.id = KVM_REG_ARM | KVM_REG_SIZE_U64 | KVM_REG_ARM_VFP;

    for (i = 0; i < 32; i++) {

        r.addr = (uintptr_t)(&env->vfp.regs[i]);

        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &r);

        if (ret) {

            return ret;

        }

        r.id++;

    }

    r.id = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_VFP |

        KVM_REG_ARM_VFP_FPSCR;

    fpscr = vfp_get_fpscr(env);

    r.addr = (uintptr_t)&fpscr;

    ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &r);

    if (ret) {

        return ret;

    }

    /* Note that we do not call write_cpustate_to_list()

     * here, so we are only writing the tuple list back to

     * KVM. This is safe because nothing can change the

     * CPUARMState cp15 fields (in particular gdb accesses cannot)

     * and so there are no changes to sync. In fact syncing would

     * be wrong at this point: for a constant register where TCG and

     * KVM disagree about its value, the preceding write_list_to_cpustate()

     * would not have had any effect on the CPUARMState value (since the

     * register is read-only), and a write_cpustate_to_list() here would

     * then try to write the TCG value back into KVM -- this would either

     * fail or incorrectly change the value the guest sees.

     *

     * If we ever want to allow the user to modify cp15 registers via

     * the gdb stub, we would need to be more clever here (for instance

     * tracking the set of registers kvm_arch_get_registers() successfully

     * managed to update the CPUARMState with, and only allowing those

     * to be written back up into the kernel).

     */

    if (!write_list_to_kvmstate(cpu)) {

        return EINVAL;

    }

    return ret;

}

int kvm_arch_get_registers(CPUState *cs)

{

    ARMCPU *cpu = ARM_CPU(cs);

    CPUARMState *env = &cpu->env;

    struct kvm_one_reg r;

    int mode, bn;

    int ret, i;

    uint32_t cpsr, fpscr;

    for (i = 0; i < ARRAY_SIZE(regs); i++) {

        r.id = regs[i].id;

        r.addr = (uintptr_t)(env) + regs[i].offset;

        ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &r);

        if (ret) {

            return ret;

        }

    }

    /* Special cases which aren't a single CPUARMState field */

    r.id = KVM_REG_ARM | KVM_REG_SIZE_U32 |

        KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(usr_regs.ARM_cpsr);

    r.addr = (uintptr_t)(&cpsr);

    ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &r);

    if (ret) {

        return ret;

    }

    cpsr_write(env, cpsr, 0xffffffff);

    /* Make sure the current mode regs are properly set */

    mode = env->uncached_cpsr & CPSR_M;

    bn = bank_number(mode);

    if (mode == ARM_CPU_MODE_FIQ) {

        memcpy(env->regs + 8, env->fiq_regs, 5 * sizeof(uint32_t));

    } else {

        memcpy(env->regs + 8, env->usr_regs, 5 * sizeof(uint32_t));

    }

    env->regs[13] = env->banked_r13[bn];

    env->regs[14] = env->banked_r14[bn];

    env->spsr = env->banked_spsr[bn];

    /* VFP registers */

    r.id = KVM_REG_ARM | KVM_REG_SIZE_U64 | KVM_REG_ARM_VFP;

    for (i = 0; i < 32; i++) {

        r.addr = (uintptr_t)(&env->vfp.regs[i]);

        ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &r);

        if (ret) {

            return ret;

        }

        r.id++;

    }

    r.id = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_VFP |

        KVM_REG_ARM_VFP_FPSCR;

    r.addr = (uintptr_t)&fpscr;

    ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &r);

    if (ret) {

        return ret;

    }

    vfp_set_fpscr(env, fpscr);

    if (!write_kvmstate_to_list(cpu)) {

        return EINVAL;

    }

    /* Note that it's OK to have registers which aren't in CPUState,

     * so we can ignore a failure return here.

     */

    write_list_to_cpustate(cpu);

    return 0;

}

void kvm_arch_reset_vcpu(CPUState *cs)

{

    /* Feed the kernel back its initial register state */

    ARMCPU *cpu = ARM_CPU(cs);

    memmove(cpu->cpreg_values, cpu->cpreg_reset_values,

            cpu->cpreg_array_len * sizeof(cpu->cpreg_values[0]));

    if (!write_list_to_kvmstate(cpu)) {

        abort();

    }

}