arch/arm64/kvm/reset.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012,2013 - ARM Ltd
   4  * Author: Marc Zyngier <marc.zyngier@arm.com>
   5  *
   6  * Derived from arch/arm/kvm/reset.c
   7  * Copyright (C) 2012 - Virtual Open Systems and Columbia University
   8  * Author: Christoffer Dall <c.dall@virtualopensystems.com>
   9  */
  10
  11 #include <linux/errno.h>
  12 #include <linux/kernel.h>
  13 #include <linux/kvm_host.h>
  14 #include <linux/kvm.h>
  15 #include <linux/hw_breakpoint.h>
  16 #include <linux/slab.h>
  17 #include <linux/string.h>
  18 #include <linux/types.h>
  19
  20 #include <kvm/arm_arch_timer.h>
  21
  22 #include <asm/cpufeature.h>
  23 #include <asm/cputype.h>
  24 #include <asm/fpsimd.h>
  25 #include <asm/ptrace.h>
  26 #include <asm/kvm_arm.h>
  27 #include <asm/kvm_asm.h>
  28 #include <asm/kvm_emulate.h>
  29 #include <asm/kvm_mmu.h>
  30 #include <asm/kvm_nested.h>
  31 #include <asm/virt.h>
  32
  33 /* Maximum phys_shift supported for any VM on this host */
  34 static u32 __ro_after_init kvm_ipa_limit;
  35 unsigned int __ro_after_init kvm_host_sve_max_vl;
  36
  37 /*
  38  * ARMv8 Reset Values
  39  */
  40 #define VCPU_RESET_PSTATE_EL1   (PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT | \
  41                                  PSR_F_BIT | PSR_D_BIT)
  42
  43 #define VCPU_RESET_PSTATE_EL2   (PSR_MODE_EL2h | PSR_A_BIT | PSR_I_BIT | \
  44                                  PSR_F_BIT | PSR_D_BIT)
  45
  46 #define VCPU_RESET_PSTATE_SVC   (PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \
  47                                  PSR_AA32_I_BIT | PSR_AA32_F_BIT)
  48
  49 unsigned int __ro_after_init kvm_sve_max_vl;
  50
  51 int __init kvm_arm_init_sve(void)
  52 {
  53         if (system_supports_sve()) {
  54                 kvm_sve_max_vl = sve_max_virtualisable_vl();
  55                 kvm_host_sve_max_vl = sve_max_vl();
  56                 kvm_nvhe_sym(kvm_host_sve_max_vl) = kvm_host_sve_max_vl;
  57
  58                 /*
  59                  * The get_sve_reg()/set_sve_reg() ioctl interface will need
  60                  * to be extended with multiple register slice support in
  61                  * order to support vector lengths greater than
  62                  * VL_ARCH_MAX:
  63                  */
  64                 if (WARN_ON(kvm_sve_max_vl > VL_ARCH_MAX))
  65                         kvm_sve_max_vl = VL_ARCH_MAX;
  66
  67                 /*
  68                  * Don't even try to make use of vector lengths that
  69                  * aren't available on all CPUs, for now:
  70                  */
  71                 if (kvm_sve_max_vl < sve_max_vl())
  72                         pr_warn("KVM: SVE vector length for guests limited to %u bytes\n",
  73                                 kvm_sve_max_vl);
  74         }
  75
  76         return 0;
  77 }
  78
  79 static void kvm_vcpu_enable_sve(struct kvm_vcpu *vcpu)
  80 {
  81         vcpu->arch.sve_max_vl = kvm_sve_max_vl;
  82
  83         /*
  84          * Userspace can still customize the vector lengths by writing
  85          * KVM_REG_ARM64_SVE_VLS.  Allocation is deferred until
  86          * kvm_arm_vcpu_finalize(), which freezes the configuration.
  87          */
  88         set_bit(KVM_ARCH_FLAG_GUEST_HAS_SVE, &vcpu->kvm->arch.flags);
  89 }
  90
  91 /*
  92  * Finalize vcpu's maximum SVE vector length, allocating
  93  * vcpu->arch.sve_state as necessary.
  94  */
  95 static int kvm_vcpu_finalize_sve(struct kvm_vcpu *vcpu)
  96 {
  97         void *buf;
  98         unsigned int vl;
  99         size_t reg_sz;
 100         int ret;
 101
 102         vl = vcpu->arch.sve_max_vl;
 103
 104         /*
 105          * Responsibility for these properties is shared between
 106          * kvm_arm_init_sve(), kvm_vcpu_enable_sve() and
 107          * set_sve_vls().  Double-check here just to be sure:
 108          */
 109         if (WARN_ON(!sve_vl_valid(vl) || vl > sve_max_virtualisable_vl() ||
 110                     vl > VL_ARCH_MAX))
 111                 return -EIO;
 112
 113         reg_sz = vcpu_sve_state_size(vcpu);
 114         buf = kzalloc(reg_sz, GFP_KERNEL_ACCOUNT);
 115         if (!buf)
 116                 return -ENOMEM;
 117
 118         ret = kvm_share_hyp(buf, buf + reg_sz);
 119         if (ret) {
 120                 kfree(buf);
 121                 return ret;
 122         }
 123
 124         vcpu->arch.sve_state = buf;
 125         vcpu_set_flag(vcpu, VCPU_SVE_FINALIZED);
 126         return 0;
 127 }
 128
 129 int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature)
 130 {
 131         switch (feature) {
 132         case KVM_ARM_VCPU_SVE:
 133                 if (!vcpu_has_sve(vcpu))
 134                         return -EINVAL;
 135
 136                 if (kvm_arm_vcpu_sve_finalized(vcpu))
 137                         return -EPERM;
 138
 139                 return kvm_vcpu_finalize_sve(vcpu);
 140         }
 141
 142         return -EINVAL;
 143 }
 144
 145 bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu)
 146 {
 147         if (vcpu_has_sve(vcpu) && !kvm_arm_vcpu_sve_finalized(vcpu))
 148                 return false;
 149
 150         return true;
 151 }
 152
 153 void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu)
 154 {
 155         void *sve_state = vcpu->arch.sve_state;
 156
 157         kvm_unshare_hyp(vcpu, vcpu + 1);
 158         if (sve_state)
 159                 kvm_unshare_hyp(sve_state, sve_state + vcpu_sve_state_size(vcpu));
 160         kfree(sve_state);
 161         free_page((unsigned long)vcpu->arch.ctxt.vncr_array);
 162         kfree(vcpu->arch.vncr_tlb);
 163         kfree(vcpu->arch.ccsidr);
 164 }
 165
 166 static void kvm_vcpu_reset_sve(struct kvm_vcpu *vcpu)
 167 {
 168         if (vcpu_has_sve(vcpu))
 169                 memset(vcpu->arch.sve_state, 0, vcpu_sve_state_size(vcpu));
 170 }
 171
 172 /**
 173  * kvm_reset_vcpu - sets core registers and sys_regs to reset value
 174  * @vcpu: The VCPU pointer
 175  *
 176  * This function sets the registers on the virtual CPU struct to their
 177  * architecturally defined reset values, except for registers whose reset is
 178  * deferred until kvm_arm_vcpu_finalize().
 179  *
 180  * Note: This function can be called from two paths: The KVM_ARM_VCPU_INIT
 181  * ioctl or as part of handling a request issued by another VCPU in the PSCI
 182  * handling code.  In the first case, the VCPU will not be loaded, and in the
 183  * second case the VCPU will be loaded.  Because this function operates purely
 184  * on the memory-backed values of system registers, we want to do a full put if
 185  * we were loaded (handling a request) and load the values back at the end of
 186  * the function.  Otherwise we leave the state alone.  In both cases, we
 187  * disable preemption around the vcpu reset as we would otherwise race with
 188  * preempt notifiers which also call put/load.
 189  */
 190 void kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 191 {
 192         struct vcpu_reset_state reset_state;
 193         bool loaded;
 194         u32 pstate;
 195
 196         spin_lock(&vcpu->arch.mp_state_lock);
 197         reset_state = vcpu->arch.reset_state;
 198         vcpu->arch.reset_state.reset = false;
 199         spin_unlock(&vcpu->arch.mp_state_lock);
 200
 201         preempt_disable();
 202         loaded = (vcpu->cpu != -1);
 203         if (loaded)
 204                 kvm_arch_vcpu_put(vcpu);
 205
 206         if (!kvm_arm_vcpu_sve_finalized(vcpu)) {
 207                 if (vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE))
 208                         kvm_vcpu_enable_sve(vcpu);
 209         } else {
 210                 kvm_vcpu_reset_sve(vcpu);
 211         }
 212
 213         if (vcpu_el1_is_32bit(vcpu))
 214                 pstate = VCPU_RESET_PSTATE_SVC;
 215         else if (vcpu_has_nv(vcpu))
 216                 pstate = VCPU_RESET_PSTATE_EL2;
 217         else
 218                 pstate = VCPU_RESET_PSTATE_EL1;
 219
 220         /* Reset core registers */
 221         memset(vcpu_gp_regs(vcpu), 0, sizeof(*vcpu_gp_regs(vcpu)));
 222         memset(&vcpu->arch.ctxt.fp_regs, 0, sizeof(vcpu->arch.ctxt.fp_regs));
 223         vcpu->arch.ctxt.spsr_abt = 0;
 224         vcpu->arch.ctxt.spsr_und = 0;
 225         vcpu->arch.ctxt.spsr_irq = 0;
 226         vcpu->arch.ctxt.spsr_fiq = 0;
 227         vcpu_gp_regs(vcpu)->pstate = pstate;
 228
 229         /* Reset system registers */
 230         kvm_reset_sys_regs(vcpu);
 231
 232         /*
 233          * Additional reset state handling that PSCI may have imposed on us.
 234          * Must be done after all the sys_reg reset.
 235          */
 236         if (reset_state.reset) {
 237                 unsigned long target_pc = reset_state.pc;
 238
 239                 /* Gracefully handle Thumb2 entry point */
 240                 if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
 241                         target_pc &= ~1UL;
 242                         vcpu_set_thumb(vcpu);
 243                 }
 244
 245                 /* Propagate caller endianness */
 246                 if (reset_state.be)
 247                         kvm_vcpu_set_be(vcpu);
 248
 249                 *vcpu_pc(vcpu) = target_pc;
 250                 vcpu_set_reg(vcpu, 0, reset_state.r0);
 251         }
 252
 253         /* Reset timer */
 254         kvm_timer_vcpu_reset(vcpu);
 255
 256         if (loaded)
 257                 kvm_arch_vcpu_load(vcpu, smp_processor_id());
 258         preempt_enable();
 259 }
 260
 261 u32 kvm_get_pa_bits(struct kvm *kvm)
 262 {
 263         /* Fixed limit until we can configure ID_AA64MMFR0.PARange */
 264         return kvm_ipa_limit;
 265 }
 266
 267 u32 get_kvm_ipa_limit(void)
 268 {
 269         return kvm_ipa_limit;
 270 }
 271
 272 int __init kvm_set_ipa_limit(void)
 273 {
 274         unsigned int parange;
 275         u64 mmfr0;
 276
 277         mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
 278         parange = cpuid_feature_extract_unsigned_field(mmfr0,
 279                                 ID_AA64MMFR0_EL1_PARANGE_SHIFT);
 280         /*
 281          * IPA size beyond 48 bits for 4K and 16K page size is only supported
 282          * when LPA2 is available. So if we have LPA2, enable it, else cap to 48
 283          * bits, in case it's reported as larger on the system.
 284          */
 285         if (!kvm_lpa2_is_enabled() && PAGE_SIZE != SZ_64K)
 286                 parange = min(parange, (unsigned int)ID_AA64MMFR0_EL1_PARANGE_48);
 287
 288         /*
 289          * Check with ARMv8.5-GTG that our PAGE_SIZE is supported at
 290          * Stage-2. If not, things will stop very quickly.
 291          */
 292         switch (cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_EL1_TGRAN_2_SHIFT)) {
 293         case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_NONE:
 294                 kvm_err("PAGE_SIZE not supported at Stage-2, giving up\n");
 295                 return -EINVAL;
 296         case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_DEFAULT:
 297                 kvm_debug("PAGE_SIZE supported at Stage-2 (default)\n");
 298                 break;
 299         case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_MIN ... ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_MAX:
 300                 kvm_debug("PAGE_SIZE supported at Stage-2 (advertised)\n");
 301                 break;
 302         default:
 303                 kvm_err("Unsupported value for TGRAN_2, giving up\n");
 304                 return -EINVAL;
 305         }
 306
 307         kvm_ipa_limit = id_aa64mmfr0_parange_to_phys_shift(parange);
 308         kvm_info("IPA Size Limit: %d bits%s\n", kvm_ipa_limit,
 309                  ((kvm_ipa_limit < KVM_PHYS_SHIFT) ?
 310                   " (Reduced IPA size, limited VM/VMM compatibility)" : ""));
 311
 312         return 0;
 313 }