/*
 * priv.c - 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 <cotte@de.ibm.com>
 *               Christian Borntraeger <borntraeger@de.ibm.com>
 */

#include <linux/kvm.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"

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->arch.guest_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;
        }

        vcpu->arch.sie_block->prefix = address;
        vcpu->arch.sie_block->ihcpu = 0xffff;

        VCPU_EVENT(vcpu, 5, "setting prefix to %x", 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->arch.guest_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);
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->arch.guest_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);
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 = stfl();
        int rc;

        vcpu->stat.instruction_stfl++;
        /* only pass the facility bits, which we can handle */
        facility_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);
        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->arch.guest_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) == -ENOSYS)
                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->arch.guest_gprs[0] & 0xf0000000) >> 28;
        int sel1 = vcpu->arch.guest_gprs[0] & 0xff;
        int sel2 = vcpu->arch.guest_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->arch.guest_gprs[base2];

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

        switch (fc) {
        case 0:
                vcpu->arch.guest_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) == -ENOSYS)
                        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;
        }
        free_page(mem);
        vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
        vcpu->arch.guest_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 priviledges 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 -ENOTSUPP;
}