// SPDX-License-Identifier: GPL-2.0
/*
 * Hosting Protected Virtual Machines
 *
 * Copyright IBM Corp. 2019, 2020
 *    Author(s): Janosch Frank <frankja@linux.ibm.com>
 */
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/pagemap.h>
#include <linux/sched/signal.h>
#include <asm/pgalloc.h>
#include <asm/gmap.h>
#include <asm/uv.h>
#include <asm/mman.h>
#include "kvm-s390.h"

int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc)
{
        int cc = 0;

        if (kvm_s390_pv_cpu_get_handle(vcpu)) {
                cc = uv_cmd_nodata(kvm_s390_pv_cpu_get_handle(vcpu),
                                   UVC_CMD_DESTROY_SEC_CPU, rc, rrc);

                KVM_UV_EVENT(vcpu->kvm, 3,
                             "PROTVIRT DESTROY VCPU %d: rc %x rrc %x",
                             vcpu->vcpu_id, *rc, *rrc);
                WARN_ONCE(cc, "protvirt destroy cpu failed rc %x rrc %x",
                          *rc, *rrc);
        }
        /* Intended memory leak for something that should never happen. */
        if (!cc)
                free_pages(vcpu->arch.pv.stor_base,
                           get_order(uv_info.guest_cpu_stor_len));

        free_page(sida_origin(vcpu->arch.sie_block));
        vcpu->arch.sie_block->pv_handle_cpu = 0;
        vcpu->arch.sie_block->pv_handle_config = 0;
        memset(&vcpu->arch.pv, 0, sizeof(vcpu->arch.pv));
        vcpu->arch.sie_block->sdf = 0;
        /*
         * The sidad field (for sdf == 2) is now the gbea field (for sdf == 0).
         * Use the reset value of gbea to avoid leaking the kernel pointer of
         * the just freed sida.
         */
        vcpu->arch.sie_block->gbea = 1;
        kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);

        return cc ? EIO : 0;
}

int kvm_s390_pv_create_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc)
{
        struct uv_cb_csc uvcb = {
                .header.cmd = UVC_CMD_CREATE_SEC_CPU,
                .header.len = sizeof(uvcb),
        };
        int cc;

        if (kvm_s390_pv_cpu_get_handle(vcpu))
                return -EINVAL;

        vcpu->arch.pv.stor_base = __get_free_pages(GFP_KERNEL,
                                                   get_order(uv_info.guest_cpu_stor_len));
        if (!vcpu->arch.pv.stor_base)
                return -ENOMEM;

        /* Input */
        uvcb.guest_handle = kvm_s390_pv_get_handle(vcpu->kvm);
        uvcb.num = vcpu->arch.sie_block->icpua;
        uvcb.state_origin = (u64)vcpu->arch.sie_block;
        uvcb.stor_origin = (u64)vcpu->arch.pv.stor_base;

        /* Alloc Secure Instruction Data Area Designation */
        vcpu->arch.sie_block->sidad = __get_free_page(GFP_KERNEL | __GFP_ZERO);
        if (!vcpu->arch.sie_block->sidad) {
                free_pages(vcpu->arch.pv.stor_base,
                           get_order(uv_info.guest_cpu_stor_len));
                return -ENOMEM;
        }

        cc = uv_call(0, (u64)&uvcb);
        *rc = uvcb.header.rc;
        *rrc = uvcb.header.rrc;
        KVM_UV_EVENT(vcpu->kvm, 3,
                     "PROTVIRT CREATE VCPU: cpu %d handle %llx rc %x rrc %x",
                     vcpu->vcpu_id, uvcb.cpu_handle, uvcb.header.rc,
                     uvcb.header.rrc);

        if (cc) {
                u16 dummy;

                kvm_s390_pv_destroy_cpu(vcpu, &dummy, &dummy);
                return -EIO;
        }

        /* Output */
        vcpu->arch.pv.handle = uvcb.cpu_handle;
        vcpu->arch.sie_block->pv_handle_cpu = uvcb.cpu_handle;
        vcpu->arch.sie_block->pv_handle_config = kvm_s390_pv_get_handle(vcpu->kvm);
        vcpu->arch.sie_block->sdf = 2;
        kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
        return 0;
}

/* only free resources when the destroy was successful */
static void kvm_s390_pv_dealloc_vm(struct kvm *kvm)
{
        vfree(kvm->arch.pv.stor_var);
        free_pages(kvm->arch.pv.stor_base,
                   get_order(uv_info.guest_base_stor_len));
        memset(&kvm->arch.pv, 0, sizeof(kvm->arch.pv));
}

static int kvm_s390_pv_alloc_vm(struct kvm *kvm)
{
        unsigned long base = uv_info.guest_base_stor_len;
        unsigned long virt = uv_info.guest_virt_var_stor_len;
        unsigned long npages = 0, vlen = 0;
        struct kvm_memory_slot *memslot;

        kvm->arch.pv.stor_var = NULL;
        kvm->arch.pv.stor_base = __get_free_pages(GFP_KERNEL, get_order(base));
        if (!kvm->arch.pv.stor_base)
                return -ENOMEM;

        /*
         * Calculate current guest storage for allocation of the
         * variable storage, which is based on the length in MB.
         *
         * Slots are sorted by GFN
         */
        mutex_lock(&kvm->slots_lock);
        memslot = kvm_memslots(kvm)->memslots;
        npages = memslot->base_gfn + memslot->npages;
        mutex_unlock(&kvm->slots_lock);

        kvm->arch.pv.guest_len = npages * PAGE_SIZE;

        /* Allocate variable storage */
        vlen = ALIGN(virt * ((npages * PAGE_SIZE) / HPAGE_SIZE), PAGE_SIZE);
        vlen += uv_info.guest_virt_base_stor_len;
        kvm->arch.pv.stor_var = vzalloc(vlen);
        if (!kvm->arch.pv.stor_var)
                goto out_err;
        return 0;

out_err:
        kvm_s390_pv_dealloc_vm(kvm);
        return -ENOMEM;
}

/* this should not fail, but if it does, we must not free the donated memory */
int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
{
        int cc;

        /* make all pages accessible before destroying the guest */
        s390_reset_acc(kvm->mm);

        cc = uv_cmd_nodata(kvm_s390_pv_get_handle(kvm),
                           UVC_CMD_DESTROY_SEC_CONF, rc, rrc);
        WRITE_ONCE(kvm->arch.gmap->guest_handle, 0);
        atomic_set(&kvm->mm->context.is_protected, 0);
        KVM_UV_EVENT(kvm, 3, "PROTVIRT DESTROY VM: rc %x rrc %x", *rc, *rrc);
        WARN_ONCE(cc, "protvirt destroy vm failed rc %x rrc %x", *rc, *rrc);
        /* Inteded memory leak on "impossible" error */
        if (!cc)
                kvm_s390_pv_dealloc_vm(kvm);
        return cc ? -EIO : 0;
}

int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
{
        struct uv_cb_cgc uvcb = {
                .header.cmd = UVC_CMD_CREATE_SEC_CONF,
                .header.len = sizeof(uvcb)
        };
        int cc, ret;
        u16 dummy;

        ret = kvm_s390_pv_alloc_vm(kvm);
        if (ret)
                return ret;

        /* Inputs */
        uvcb.guest_stor_origin = 0; /* MSO is 0 for KVM */
        uvcb.guest_stor_len = kvm->arch.pv.guest_len;
        uvcb.guest_asce = kvm->arch.gmap->asce;
        uvcb.guest_sca = (unsigned long)kvm->arch.sca;
        uvcb.conf_base_stor_origin = (u64)kvm->arch.pv.stor_base;
        uvcb.conf_virt_stor_origin = (u64)kvm->arch.pv.stor_var;

        cc = uv_call(0, (u64)&uvcb);
        *rc = uvcb.header.rc;
        *rrc = uvcb.header.rrc;
        KVM_UV_EVENT(kvm, 3, "PROTVIRT CREATE VM: handle %llx len %llx rc %x rrc %x",
                     uvcb.guest_handle, uvcb.guest_stor_len, *rc, *rrc);

        /* Outputs */
        kvm->arch.pv.handle = uvcb.guest_handle;

        if (cc) {
                if (uvcb.header.rc & UVC_RC_NEED_DESTROY)
                        kvm_s390_pv_deinit_vm(kvm, &dummy, &dummy);
                else
                        kvm_s390_pv_dealloc_vm(kvm);
                return -EIO;
        }
        kvm->arch.gmap->guest_handle = uvcb.guest_handle;
        atomic_set(&kvm->mm->context.is_protected, 1);
        return 0;
}

int kvm_s390_pv_set_sec_parms(struct kvm *kvm, void *hdr, u64 length, u16 *rc,
                              u16 *rrc)
{
        struct uv_cb_ssc uvcb = {
                .header.cmd = UVC_CMD_SET_SEC_CONF_PARAMS,
                .header.len = sizeof(uvcb),
                .sec_header_origin = (u64)hdr,
                .sec_header_len = length,
                .guest_handle = kvm_s390_pv_get_handle(kvm),
        };
        int cc = uv_call(0, (u64)&uvcb);

        *rc = uvcb.header.rc;
        *rrc = uvcb.header.rrc;
        KVM_UV_EVENT(kvm, 3, "PROTVIRT VM SET PARMS: rc %x rrc %x",
                     *rc, *rrc);
        return cc ? -EINVAL : 0;
}

static int unpack_one(struct kvm *kvm, unsigned long addr, u64 tweak,
                      u64 offset, u16 *rc, u16 *rrc)
{
        struct uv_cb_unp uvcb = {
                .header.cmd = UVC_CMD_UNPACK_IMG,
                .header.len = sizeof(uvcb),
                .guest_handle = kvm_s390_pv_get_handle(kvm),
                .gaddr = addr,
                .tweak[0] = tweak,
                .tweak[1] = offset,
        };
        int ret = gmap_make_secure(kvm->arch.gmap, addr, &uvcb);

        *rc = uvcb.header.rc;
        *rrc = uvcb.header.rrc;

        if (ret && ret != -EAGAIN)
                KVM_UV_EVENT(kvm, 3, "PROTVIRT VM UNPACK: failed addr %llx with rc %x rrc %x",
                             uvcb.gaddr, *rc, *rrc);
        return ret;
}

int kvm_s390_pv_unpack(struct kvm *kvm, unsigned long addr, unsigned long size,
                       unsigned long tweak, u16 *rc, u16 *rrc)
{
        u64 offset = 0;
        int ret = 0;

        if (addr & ~PAGE_MASK || !size || size & ~PAGE_MASK)
                return -EINVAL;

        KVM_UV_EVENT(kvm, 3, "PROTVIRT VM UNPACK: start addr %lx size %lx",
                     addr, size);

        while (offset < size) {
                ret = unpack_one(kvm, addr, tweak, offset, rc, rrc);
                if (ret == -EAGAIN) {
                        cond_resched();
                        if (fatal_signal_pending(current))
                                break;
                        continue;
                }
                if (ret)
                        break;
                addr += PAGE_SIZE;
                offset += PAGE_SIZE;
        }
        if (!ret)
                KVM_UV_EVENT(kvm, 3, "%s", "PROTVIRT VM UNPACK: successful");
        return ret;
}

int kvm_s390_pv_set_cpu_state(struct kvm_vcpu *vcpu, u8 state)
{
        struct uv_cb_cpu_set_state uvcb = {
                .header.cmd     = UVC_CMD_CPU_SET_STATE,
                .header.len     = sizeof(uvcb),
                .cpu_handle     = kvm_s390_pv_cpu_get_handle(vcpu),
                .state          = state,
        };
        int cc;

        cc = uv_call(0, (u64)&uvcb);
        KVM_UV_EVENT(vcpu->kvm, 3, "PROTVIRT SET CPU %d STATE %d rc %x rrc %x",
                     vcpu->vcpu_id, state, uvcb.header.rc, uvcb.header.rrc);
        if (cc)
                return -EINVAL;
        return 0;
}