priv.c

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/*
 * handling privileged instructions
 *
 * Copyright IBM Corp. 2008
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (version 2 only)
 * as published by the Free Software Foundation.
 *
 *    Author(s): Carsten Otte <[email protected]>
 *               Christian Borntraeger <[email protected]>
 */

#include <linux/kvm.h>
#include <linux/gfp.h>
#include <linux/errno.h>
#include <asm/current.h>
#include <asm/debug.h>
#include <asm/ebcdic.h>
#include <asm/sysinfo.h>
#include "gaccess.h"
#include "kvm-s390.h"
#include "trace.h"

static int handle_set_prefix(struct kvm_vcpu *vcpu)
{
    int base2 = vcpu->arch.sie_block->ipb >> 28;
    int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
    u64 operand2;
    u32 address = 0;
    u8 tmp;

    vcpu->stat.instruction_spx++;

    operand2 = disp2;
    if (base2)
        operand2 += vcpu->run->s.regs.gprs[base2];

    /* must be word boundary */
    if (operand2 & 3) {
        kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
        goto out;
    }

    /* get the value */
    if (get_guest_u32(vcpu, operand2, &address)) {
        kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
        goto out;
    }

    address = address & 0x7fffe000u;

    /* make sure that the new value is valid memory */
    if (copy_from_guest_absolute(vcpu, &tmp, address, 1) ||
       (copy_from_guest_absolute(vcpu, &tmp, address + PAGE_SIZE, 1))) {
        kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
        goto out;
    }

    kvm_s390_set_prefix(vcpu, address);

    VCPU_EVENT(vcpu, 5, "setting prefix to %x", address);
    trace_kvm_s390_handle_prefix(vcpu, 1, address);
out:
    return 0;
}

static int handle_store_prefix(struct kvm_vcpu *vcpu)
{
    int base2 = vcpu->arch.sie_block->ipb >> 28;
    int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
    u64 operand2;
    u32 address;

    vcpu->stat.instruction_stpx++;
    operand2 = disp2;
    if (base2)
        operand2 += vcpu->run->s.regs.gprs[base2];

    /* must be word boundary */
    if (operand2 & 3) {
        kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
        goto out;
    }

    address = vcpu->arch.sie_block->prefix;
    address = address & 0x7fffe000u;

    /* get the value */
    if (put_guest_u32(vcpu, operand2, address)) {
        kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
        goto out;
    }

    VCPU_EVENT(vcpu, 5, "storing prefix to %x", address);
    trace_kvm_s390_handle_prefix(vcpu, 0, address);
out:
    return 0;
}

static int handle_store_cpu_address(struct kvm_vcpu *vcpu)
{
    int base2 = vcpu->arch.sie_block->ipb >> 28;
    int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
    u64 useraddr;
    int rc;

    vcpu->stat.instruction_stap++;
    useraddr = disp2;
    if (base2)
        useraddr += vcpu->run->s.regs.gprs[base2];

    if (useraddr & 1) {
        kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
        goto out;
    }

    rc = put_guest_u16(vcpu, useraddr, vcpu->vcpu_id);
    if (rc == -EFAULT) {
        kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
        goto out;
    }

    VCPU_EVENT(vcpu, 5, "storing cpu address to %llx", useraddr);
    trace_kvm_s390_handle_stap(vcpu, useraddr);
out:
    return 0;
}

static int handle_skey(struct kvm_vcpu *vcpu)
{
    vcpu->stat.instruction_storage_key++;
    vcpu->arch.sie_block->gpsw.addr -= 4;
    VCPU_EVENT(vcpu, 4, "%s", "retrying storage key operation");
    return 0;
}

static int handle_stsch(struct kvm_vcpu *vcpu)
{
    vcpu->stat.instruction_stsch++;
    VCPU_EVENT(vcpu, 4, "%s", "store subchannel - CC3");
    /* condition code 3 */
    vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
    vcpu->arch.sie_block->gpsw.mask |= (3 & 3ul) << 44;
    return 0;
}

static int handle_chsc(struct kvm_vcpu *vcpu)
{
    vcpu->stat.instruction_chsc++;
    VCPU_EVENT(vcpu, 4, "%s", "channel subsystem call - CC3");
    /* condition code 3 */
    vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
    vcpu->arch.sie_block->gpsw.mask |= (3 & 3ul) << 44;
    return 0;
}

static int handle_stfl(struct kvm_vcpu *vcpu)
{
    unsigned int facility_list;
    int rc;

    vcpu->stat.instruction_stfl++;
    /* only pass the facility bits, which we can handle */
    facility_list = S390_lowcore.stfl_fac_list & 0xff00fff3;

    rc = copy_to_guest(vcpu, offsetof(struct _lowcore, stfl_fac_list),
               &facility_list, sizeof(facility_list));
    if (rc == -EFAULT)
        kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
    else {
        VCPU_EVENT(vcpu, 5, "store facility list value %x",
               facility_list);
        trace_kvm_s390_handle_stfl(vcpu, facility_list);
    }
    return 0;
}

static int handle_stidp(struct kvm_vcpu *vcpu)
{
    int base2 = vcpu->arch.sie_block->ipb >> 28;
    int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
    u64 operand2;
    int rc;

    vcpu->stat.instruction_stidp++;
    operand2 = disp2;
    if (base2)
        operand2 += vcpu->run->s.regs.gprs[base2];

    if (operand2 & 7) {
        kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
        goto out;
    }

    rc = put_guest_u64(vcpu, operand2, vcpu->arch.stidp_data);
    if (rc == -EFAULT) {
        kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
        goto out;
    }

    VCPU_EVENT(vcpu, 5, "%s", "store cpu id");
out:
    return 0;
}

static void handle_stsi_3_2_2(struct kvm_vcpu *vcpu, struct sysinfo_3_2_2 *mem)
{
    struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
    int cpus = 0;
    int n;

    spin_lock(&fi->lock);
    for (n = 0; n < KVM_MAX_VCPUS; n++)
        if (fi->local_int[n])
            cpus++;
    spin_unlock(&fi->lock);

    /* deal with other level 3 hypervisors */
    if (stsi(mem, 3, 2, 2))
        mem->count = 0;
    if (mem->count < 8)
        mem->count++;
    for (n = mem->count - 1; n > 0 ; n--)
        memcpy(&mem->vm[n], &mem->vm[n - 1], sizeof(mem->vm[0]));

    mem->vm[0].cpus_total = cpus;
    mem->vm[0].cpus_configured = cpus;
    mem->vm[0].cpus_standby = 0;
    mem->vm[0].cpus_reserved = 0;
    mem->vm[0].caf = 1000;
    memcpy(mem->vm[0].name, "KVMguest", 8);
    ASCEBC(mem->vm[0].name, 8);
    memcpy(mem->vm[0].cpi, "KVM/Linux       ", 16);
    ASCEBC(mem->vm[0].cpi, 16);
}

static int handle_stsi(struct kvm_vcpu *vcpu)
{
    int fc = (vcpu->run->s.regs.gprs[0] & 0xf0000000) >> 28;
    int sel1 = vcpu->run->s.regs.gprs[0] & 0xff;
    int sel2 = vcpu->run->s.regs.gprs[1] & 0xffff;
    int base2 = vcpu->arch.sie_block->ipb >> 28;
    int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
    u64 operand2;
    unsigned long mem;

    vcpu->stat.instruction_stsi++;
    VCPU_EVENT(vcpu, 4, "stsi: fc: %x sel1: %x sel2: %x", fc, sel1, sel2);

    operand2 = disp2;
    if (base2)
        operand2 += vcpu->run->s.regs.gprs[base2];

    if (operand2 & 0xfff && fc > 0)
        return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

    switch (fc) {
    case 0:
        vcpu->run->s.regs.gprs[0] = 3 << 28;
        vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
        return 0;
    case 1: /* same handling for 1 and 2 */
    case 2:
        mem = get_zeroed_page(GFP_KERNEL);
        if (!mem)
            goto out_fail;
        if (stsi((void *) mem, fc, sel1, sel2))
            goto out_mem;
        break;
    case 3:
        if (sel1 != 2 || sel2 != 2)
            goto out_fail;
        mem = get_zeroed_page(GFP_KERNEL);
        if (!mem)
            goto out_fail;
        handle_stsi_3_2_2(vcpu, (void *) mem);
        break;
    default:
        goto out_fail;
    }

    if (copy_to_guest_absolute(vcpu, operand2, (void *) mem, PAGE_SIZE)) {
        kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
        goto out_mem;
    }
    trace_kvm_s390_handle_stsi(vcpu, fc, sel1, sel2, operand2);
    free_page(mem);
    vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
    vcpu->run->s.regs.gprs[0] = 0;
    return 0;
out_mem:
    free_page(mem);
out_fail:
    /* condition code 3 */
    vcpu->arch.sie_block->gpsw.mask |= 3ul << 44;
    return 0;
}

static intercept_handler_t priv_handlers[256] = {
    [0x02] = handle_stidp,
    [0x10] = handle_set_prefix,
    [0x11] = handle_store_prefix,
    [0x12] = handle_store_cpu_address,
    [0x29] = handle_skey,
    [0x2a] = handle_skey,
    [0x2b] = handle_skey,
    [0x34] = handle_stsch,
    [0x5f] = handle_chsc,
    [0x7d] = handle_stsi,
    [0xb1] = handle_stfl,
};

int kvm_s390_handle_b2(struct kvm_vcpu *vcpu)
{
    intercept_handler_t handler;

    /*
     * a lot of B2 instructions are priviledged. We first check for
     * the privileged ones, that we can handle in the kernel. If the
     * kernel can handle this instruction, we check for the problem
     * state bit and (a) handle the instruction or (b) send a code 2
     * program check.
     * Anything else goes to userspace.*/
    handler = priv_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
    if (handler) {
        if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
            return kvm_s390_inject_program_int(vcpu,
                           PGM_PRIVILEGED_OPERATION);
        else
            return handler(vcpu);
    }
    return -EOPNOTSUPP;
}

static int handle_tprot(struct kvm_vcpu *vcpu)
{
    int base1 = (vcpu->arch.sie_block->ipb & 0xf0000000) >> 28;
    int disp1 = (vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16;
    int base2 = (vcpu->arch.sie_block->ipb & 0xf000) >> 12;
    int disp2 = vcpu->arch.sie_block->ipb & 0x0fff;
    u64 address1 = disp1 + base1 ? vcpu->run->s.regs.gprs[base1] : 0;
    u64 address2 = disp2 + base2 ? vcpu->run->s.regs.gprs[base2] : 0;
    struct vm_area_struct *vma;
    unsigned long user_address;

    vcpu->stat.instruction_tprot++;

    /* we only handle the Linux memory detection case:
     * access key == 0
     * guest DAT == off
     * everything else goes to userspace. */
    if (address2 & 0xf0)
        return -EOPNOTSUPP;
    if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
        return -EOPNOTSUPP;


    /* we must resolve the address without holding the mmap semaphore.
     * This is ok since the userspace hypervisor is not supposed to change
     * the mapping while the guest queries the memory. Otherwise the guest
     * might crash or get wrong info anyway. */
    user_address = (unsigned long) __guestaddr_to_user(vcpu, address1);

    down_read(&current->mm->mmap_sem);
    vma = find_vma(current->mm, user_address);
    if (!vma) {
        up_read(&current->mm->mmap_sem);
        return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
    }

    vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
    if (!(vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_READ))
        vcpu->arch.sie_block->gpsw.mask |= (1ul << 44);
    if (!(vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_READ))
        vcpu->arch.sie_block->gpsw.mask |= (2ul << 44);

    up_read(&current->mm->mmap_sem);
    return 0;
}

int kvm_s390_handle_e5(struct kvm_vcpu *vcpu)
{
    /* For e5xx... instructions we only handle TPROT */
    if ((vcpu->arch.sie_block->ipa & 0x00ff) == 0x01)
        return handle_tprot(vcpu);
    return -EOPNOTSUPP;
}

static int handle_sckpf(struct kvm_vcpu *vcpu)
{
    u32 value;

    if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
        return kvm_s390_inject_program_int(vcpu,
                           PGM_PRIVILEGED_OPERATION);

    if (vcpu->run->s.regs.gprs[0] & 0x00000000ffff0000)
        return kvm_s390_inject_program_int(vcpu,
                           PGM_SPECIFICATION);

    value = vcpu->run->s.regs.gprs[0] & 0x000000000000ffff;
    vcpu->arch.sie_block->todpr = value;

    return 0;
}

static intercept_handler_t x01_handlers[256] = {
    [0x07] = handle_sckpf,
};

int kvm_s390_handle_01(struct kvm_vcpu *vcpu)
{
    intercept_handler_t handler;

    handler = x01_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
    if (handler)
        return handler(vcpu);
    return -EOPNOTSUPP;
}