arch/s390/kvm/pv.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Hosting Protected Virtual Machines
   4  *
   5  * Copyright IBM Corp. 2019, 2020
   6  *    Author(s): Janosch Frank <frankja@linux.ibm.com>
   7  */
   8 #include <linux/kvm.h>
   9 #include <linux/kvm_host.h>
  10 #include <linux/pagemap.h>
  11 #include <linux/sched/signal.h>
  12 #include <asm/gmap.h>
  13 #include <asm/uv.h>
  14 #include <asm/mman.h>
  15 #include "kvm-s390.h"
  16
  17 int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc)
  18 {
  19         int cc = 0;
  20
  21         if (kvm_s390_pv_cpu_get_handle(vcpu)) {
  22                 cc = uv_cmd_nodata(kvm_s390_pv_cpu_get_handle(vcpu),
  23                                    UVC_CMD_DESTROY_SEC_CPU, rc, rrc);
  24
  25                 KVM_UV_EVENT(vcpu->kvm, 3,
  26                              "PROTVIRT DESTROY VCPU %d: rc %x rrc %x",
  27                              vcpu->vcpu_id, *rc, *rrc);
  28                 WARN_ONCE(cc, "protvirt destroy cpu failed rc %x rrc %x",
  29                           *rc, *rrc);
  30         }
  31         /* Intended memory leak for something that should never happen. */
  32         if (!cc)
  33                 free_pages(vcpu->arch.pv.stor_base,
  34                            get_order(uv_info.guest_cpu_stor_len));
  35
  36         free_page(sida_origin(vcpu->arch.sie_block));
  37         vcpu->arch.sie_block->pv_handle_cpu = 0;
  38         vcpu->arch.sie_block->pv_handle_config = 0;
  39         memset(&vcpu->arch.pv, 0, sizeof(vcpu->arch.pv));
  40         vcpu->arch.sie_block->sdf = 0;
  41         /*
  42          * The sidad field (for sdf == 2) is now the gbea field (for sdf == 0).
  43          * Use the reset value of gbea to avoid leaking the kernel pointer of
  44          * the just freed sida.
  45          */
  46         vcpu->arch.sie_block->gbea = 1;
  47         kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
  48
  49         return cc ? EIO : 0;
  50 }
  51
  52 int kvm_s390_pv_create_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc)
  53 {
  54         struct uv_cb_csc uvcb = {
  55                 .header.cmd = UVC_CMD_CREATE_SEC_CPU,
  56                 .header.len = sizeof(uvcb),
  57         };
  58         int cc;
  59
  60         if (kvm_s390_pv_cpu_get_handle(vcpu))
  61                 return -EINVAL;
  62
  63         vcpu->arch.pv.stor_base = __get_free_pages(GFP_KERNEL_ACCOUNT,
  64                                                    get_order(uv_info.guest_cpu_stor_len));
  65         if (!vcpu->arch.pv.stor_base)
  66                 return -ENOMEM;
  67
  68         /* Input */
  69         uvcb.guest_handle = kvm_s390_pv_get_handle(vcpu->kvm);
  70         uvcb.num = vcpu->arch.sie_block->icpua;
  71         uvcb.state_origin = (u64)vcpu->arch.sie_block;
  72         uvcb.stor_origin = (u64)vcpu->arch.pv.stor_base;
  73
  74         /* Alloc Secure Instruction Data Area Designation */
  75         vcpu->arch.sie_block->sidad = __get_free_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
  76         if (!vcpu->arch.sie_block->sidad) {
  77                 free_pages(vcpu->arch.pv.stor_base,
  78                            get_order(uv_info.guest_cpu_stor_len));
  79                 return -ENOMEM;
  80         }
  81
  82         cc = uv_call(0, (u64)&uvcb);
  83         *rc = uvcb.header.rc;
  84         *rrc = uvcb.header.rrc;
  85         KVM_UV_EVENT(vcpu->kvm, 3,
  86                      "PROTVIRT CREATE VCPU: cpu %d handle %llx rc %x rrc %x",
  87                      vcpu->vcpu_id, uvcb.cpu_handle, uvcb.header.rc,
  88                      uvcb.header.rrc);
  89
  90         if (cc) {
  91                 u16 dummy;
  92
  93                 kvm_s390_pv_destroy_cpu(vcpu, &dummy, &dummy);
  94                 return -EIO;
  95         }
  96
  97         /* Output */
  98         vcpu->arch.pv.handle = uvcb.cpu_handle;
  99         vcpu->arch.sie_block->pv_handle_cpu = uvcb.cpu_handle;
 100         vcpu->arch.sie_block->pv_handle_config = kvm_s390_pv_get_handle(vcpu->kvm);
 101         vcpu->arch.sie_block->sdf = 2;
 102         kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
 103         return 0;
 104 }
 105
 106 /* only free resources when the destroy was successful */
 107 static void kvm_s390_pv_dealloc_vm(struct kvm *kvm)
 108 {
 109         vfree(kvm->arch.pv.stor_var);
 110         free_pages(kvm->arch.pv.stor_base,
 111                    get_order(uv_info.guest_base_stor_len));
 112         memset(&kvm->arch.pv, 0, sizeof(kvm->arch.pv));
 113 }
 114
 115 static int kvm_s390_pv_alloc_vm(struct kvm *kvm)
 116 {
 117         unsigned long base = uv_info.guest_base_stor_len;
 118         unsigned long virt = uv_info.guest_virt_var_stor_len;
 119         unsigned long npages = 0, vlen = 0;
 120         struct kvm_memory_slot *memslot;
 121
 122         kvm->arch.pv.stor_var = NULL;
 123         kvm->arch.pv.stor_base = __get_free_pages(GFP_KERNEL_ACCOUNT, get_order(base));
 124         if (!kvm->arch.pv.stor_base)
 125                 return -ENOMEM;
 126
 127         /*
 128          * Calculate current guest storage for allocation of the
 129          * variable storage, which is based on the length in MB.
 130          *
 131          * Slots are sorted by GFN
 132          */
 133         mutex_lock(&kvm->slots_lock);
 134         memslot = kvm_memslots(kvm)->memslots;
 135         npages = memslot->base_gfn + memslot->npages;
 136         mutex_unlock(&kvm->slots_lock);
 137
 138         kvm->arch.pv.guest_len = npages * PAGE_SIZE;
 139
 140         /* Allocate variable storage */
 141         vlen = ALIGN(virt * ((npages * PAGE_SIZE) / HPAGE_SIZE), PAGE_SIZE);
 142         vlen += uv_info.guest_virt_base_stor_len;
 143         /*
 144          * The Create Secure Configuration Ultravisor Call does not support
 145          * using large pages for the virtual memory area.
 146          * This is a hardware limitation.
 147          */
 148         kvm->arch.pv.stor_var = vmalloc_no_huge(vlen);
 149         if (!kvm->arch.pv.stor_var)
 150                 goto out_err;
 151         return 0;
 152
 153 out_err:
 154         kvm_s390_pv_dealloc_vm(kvm);
 155         return -ENOMEM;
 156 }
 157
 158 /* this should not fail, but if it does, we must not free the donated memory */
 159 int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
 160 {
 161         int cc;
 162
 163         /* make all pages accessible before destroying the guest */
 164         s390_reset_acc(kvm->mm);
 165
 166         cc = uv_cmd_nodata(kvm_s390_pv_get_handle(kvm),
 167                            UVC_CMD_DESTROY_SEC_CONF, rc, rrc);
 168         WRITE_ONCE(kvm->arch.gmap->guest_handle, 0);
 169         atomic_set(&kvm->mm->context.is_protected, 0);
 170         KVM_UV_EVENT(kvm, 3, "PROTVIRT DESTROY VM: rc %x rrc %x", *rc, *rrc);
 171         WARN_ONCE(cc, "protvirt destroy vm failed rc %x rrc %x", *rc, *rrc);
 172         /* Inteded memory leak on "impossible" error */
 173         if (!cc)
 174                 kvm_s390_pv_dealloc_vm(kvm);
 175         return cc ? -EIO : 0;
 176 }
 177
 178 int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
 179 {
 180         struct uv_cb_cgc uvcb = {
 181                 .header.cmd = UVC_CMD_CREATE_SEC_CONF,
 182                 .header.len = sizeof(uvcb)
 183         };
 184         int cc, ret;
 185         u16 dummy;
 186
 187         ret = kvm_s390_pv_alloc_vm(kvm);
 188         if (ret)
 189                 return ret;
 190
 191         /* Inputs */
 192         uvcb.guest_stor_origin = 0; /* MSO is 0 for KVM */
 193         uvcb.guest_stor_len = kvm->arch.pv.guest_len;
 194         uvcb.guest_asce = kvm->arch.gmap->asce;
 195         uvcb.guest_sca = (unsigned long)kvm->arch.sca;
 196         uvcb.conf_base_stor_origin = (u64)kvm->arch.pv.stor_base;
 197         uvcb.conf_virt_stor_origin = (u64)kvm->arch.pv.stor_var;
 198
 199         cc = uv_call(0, (u64)&uvcb);
 200         *rc = uvcb.header.rc;
 201         *rrc = uvcb.header.rrc;
 202         KVM_UV_EVENT(kvm, 3, "PROTVIRT CREATE VM: handle %llx len %llx rc %x rrc %x",
 203                      uvcb.guest_handle, uvcb.guest_stor_len, *rc, *rrc);
 204
 205         /* Outputs */
 206         kvm->arch.pv.handle = uvcb.guest_handle;
 207
 208         if (cc) {
 209                 if (uvcb.header.rc & UVC_RC_NEED_DESTROY)
 210                         kvm_s390_pv_deinit_vm(kvm, &dummy, &dummy);
 211                 else
 212                         kvm_s390_pv_dealloc_vm(kvm);
 213                 return -EIO;
 214         }
 215         kvm->arch.gmap->guest_handle = uvcb.guest_handle;
 216         return 0;
 217 }
 218
 219 int kvm_s390_pv_set_sec_parms(struct kvm *kvm, void *hdr, u64 length, u16 *rc,
 220                               u16 *rrc)
 221 {
 222         struct uv_cb_ssc uvcb = {
 223                 .header.cmd = UVC_CMD_SET_SEC_CONF_PARAMS,
 224                 .header.len = sizeof(uvcb),
 225                 .sec_header_origin = (u64)hdr,
 226                 .sec_header_len = length,
 227                 .guest_handle = kvm_s390_pv_get_handle(kvm),
 228         };
 229         int cc = uv_call(0, (u64)&uvcb);
 230
 231         *rc = uvcb.header.rc;
 232         *rrc = uvcb.header.rrc;
 233         KVM_UV_EVENT(kvm, 3, "PROTVIRT VM SET PARMS: rc %x rrc %x",
 234                      *rc, *rrc);
 235         if (!cc)
 236                 atomic_set(&kvm->mm->context.is_protected, 1);
 237         return cc ? -EINVAL : 0;
 238 }
 239
 240 static int unpack_one(struct kvm *kvm, unsigned long addr, u64 tweak,
 241                       u64 offset, u16 *rc, u16 *rrc)
 242 {
 243         struct uv_cb_unp uvcb = {
 244                 .header.cmd = UVC_CMD_UNPACK_IMG,
 245                 .header.len = sizeof(uvcb),
 246                 .guest_handle = kvm_s390_pv_get_handle(kvm),
 247                 .gaddr = addr,
 248                 .tweak[0] = tweak,
 249                 .tweak[1] = offset,
 250         };
 251         int ret = gmap_make_secure(kvm->arch.gmap, addr, &uvcb);
 252
 253         *rc = uvcb.header.rc;
 254         *rrc = uvcb.header.rrc;
 255
 256         if (ret && ret != -EAGAIN)
 257                 KVM_UV_EVENT(kvm, 3, "PROTVIRT VM UNPACK: failed addr %llx with rc %x rrc %x",
 258                              uvcb.gaddr, *rc, *rrc);
 259         return ret;
 260 }
 261
 262 int kvm_s390_pv_unpack(struct kvm *kvm, unsigned long addr, unsigned long size,
 263                        unsigned long tweak, u16 *rc, u16 *rrc)
 264 {
 265         u64 offset = 0;
 266         int ret = 0;
 267
 268         if (addr & ~PAGE_MASK || !size || size & ~PAGE_MASK)
 269                 return -EINVAL;
 270
 271         KVM_UV_EVENT(kvm, 3, "PROTVIRT VM UNPACK: start addr %lx size %lx",
 272                      addr, size);
 273
 274         while (offset < size) {
 275                 ret = unpack_one(kvm, addr, tweak, offset, rc, rrc);
 276                 if (ret == -EAGAIN) {
 277                         cond_resched();
 278                         if (fatal_signal_pending(current))
 279                                 break;
 280                         continue;
 281                 }
 282                 if (ret)
 283                         break;
 284                 addr += PAGE_SIZE;
 285                 offset += PAGE_SIZE;
 286         }
 287         if (!ret)
 288                 KVM_UV_EVENT(kvm, 3, "%s", "PROTVIRT VM UNPACK: successful");
 289         return ret;
 290 }
 291
 292 int kvm_s390_pv_set_cpu_state(struct kvm_vcpu *vcpu, u8 state)
 293 {
 294         struct uv_cb_cpu_set_state uvcb = {
 295                 .header.cmd     = UVC_CMD_CPU_SET_STATE,
 296                 .header.len     = sizeof(uvcb),
 297                 .cpu_handle     = kvm_s390_pv_cpu_get_handle(vcpu),
 298                 .state          = state,
 299         };
 300         int cc;
 301
 302         cc = uv_call(0, (u64)&uvcb);
 303         KVM_UV_EVENT(vcpu->kvm, 3, "PROTVIRT SET CPU %d STATE %d rc %x rrc %x",
 304                      vcpu->vcpu_id, state, uvcb.header.rc, uvcb.header.rrc);
 305         if (cc)
 306                 return -EINVAL;
 307         return 0;
 308 }