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
  36 /*
  37  * ARMv8 Reset Values
  38  */
  39 #define VCPU_RESET_PSTATE_EL1   (PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT | \
  40                                  PSR_F_BIT | PSR_D_BIT)
  41
  42 #define VCPU_RESET_PSTATE_EL2   (PSR_MODE_EL2h | PSR_A_BIT | PSR_I_BIT | \
  43                                  PSR_F_BIT | PSR_D_BIT)
  44
  45 #define VCPU_RESET_PSTATE_SVC   (PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \
  46                                  PSR_AA32_I_BIT | PSR_AA32_F_BIT)
  47
  48 unsigned int __ro_after_init kvm_sve_max_vl;
  49
  50 int __init kvm_arm_init_sve(void)
  51 {
  52         if (system_supports_sve()) {
  53                 kvm_sve_max_vl = sve_max_virtualisable_vl();
  54
  55                 /*
  56                  * The get_sve_reg()/set_sve_reg() ioctl interface will need
  57                  * to be extended with multiple register slice support in
  58                  * order to support vector lengths greater than
  59                  * VL_ARCH_MAX:
  60                  */
  61                 if (WARN_ON(kvm_sve_max_vl > VL_ARCH_MAX))
  62                         kvm_sve_max_vl = VL_ARCH_MAX;
  63
  64                 /*
  65                  * Don't even try to make use of vector lengths that
  66                  * aren't available on all CPUs, for now:
  67                  */
  68                 if (kvm_sve_max_vl < sve_max_vl())
  69                         pr_warn("KVM: SVE vector length for guests limited to %u bytes\n",
  70                                 kvm_sve_max_vl);
  71         }
  72
  73         return 0;
  74 }
  75
  76 static void kvm_vcpu_enable_sve(struct kvm_vcpu *vcpu)
  77 {
  78         vcpu->arch.sve_max_vl = kvm_sve_max_vl;
  79
  80         /*
  81          * Userspace can still customize the vector lengths by writing
  82          * KVM_REG_ARM64_SVE_VLS.  Allocation is deferred until
  83          * kvm_arm_vcpu_finalize(), which freezes the configuration.
  84          */
  85         vcpu_set_flag(vcpu, GUEST_HAS_SVE);
  86 }
  87
  88 /*
  89  * Finalize vcpu's maximum SVE vector length, allocating
  90  * vcpu->arch.sve_state as necessary.
  91  */
  92 static int kvm_vcpu_finalize_sve(struct kvm_vcpu *vcpu)
  93 {
  94         void *buf;
  95         unsigned int vl;
  96         size_t reg_sz;
  97         int ret;
  98
  99         vl = vcpu->arch.sve_max_vl;
 100
 101         /*
 102          * Responsibility for these properties is shared between
 103          * kvm_arm_init_sve(), kvm_vcpu_enable_sve() and
 104          * set_sve_vls().  Double-check here just to be sure:
 105          */
 106         if (WARN_ON(!sve_vl_valid(vl) || vl > sve_max_virtualisable_vl() ||
 107                     vl > VL_ARCH_MAX))
 108                 return -EIO;
 109
 110         reg_sz = vcpu_sve_state_size(vcpu);
 111         buf = kzalloc(reg_sz, GFP_KERNEL_ACCOUNT);
 112         if (!buf)
 113                 return -ENOMEM;
 114
 115         ret = kvm_share_hyp(buf, buf + reg_sz);
 116         if (ret) {
 117                 kfree(buf);
 118                 return ret;
 119         }
 120
 121         vcpu->arch.sve_state = buf;
 122         vcpu_set_flag(vcpu, VCPU_SVE_FINALIZED);
 123         return 0;
 124 }
 125
 126 int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature)
 127 {
 128         switch (feature) {
 129         case KVM_ARM_VCPU_SVE:
 130                 if (!vcpu_has_sve(vcpu))
 131                         return -EINVAL;
 132
 133                 if (kvm_arm_vcpu_sve_finalized(vcpu))
 134                         return -EPERM;
 135
 136                 return kvm_vcpu_finalize_sve(vcpu);
 137         }
 138
 139         return -EINVAL;
 140 }
 141
 142 bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu)
 143 {
 144         if (vcpu_has_sve(vcpu) && !kvm_arm_vcpu_sve_finalized(vcpu))
 145                 return false;
 146
 147         return true;
 148 }
 149
 150 void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu)
 151 {
 152         void *sve_state = vcpu->arch.sve_state;
 153
 154         kvm_vcpu_unshare_task_fp(vcpu);
 155         kvm_unshare_hyp(vcpu, vcpu + 1);
 156         if (sve_state)
 157                 kvm_unshare_hyp(sve_state, sve_state + vcpu_sve_state_size(vcpu));
 158         kfree(sve_state);
 159         kfree(vcpu->arch.ccsidr);
 160 }
 161
 162 static void kvm_vcpu_reset_sve(struct kvm_vcpu *vcpu)
 163 {
 164         if (vcpu_has_sve(vcpu))
 165                 memset(vcpu->arch.sve_state, 0, vcpu_sve_state_size(vcpu));
 166 }
 167
 168 static void kvm_vcpu_enable_ptrauth(struct kvm_vcpu *vcpu)
 169 {
 170         vcpu_set_flag(vcpu, GUEST_HAS_PTRAUTH);
 171 }
 172
 173 /**
 174  * kvm_reset_vcpu - sets core registers and sys_regs to reset value
 175  * @vcpu: The VCPU pointer
 176  *
 177  * This function sets the registers on the virtual CPU struct to their
 178  * architecturally defined reset values, except for registers whose reset is
 179  * deferred until kvm_arm_vcpu_finalize().
 180  *
 181  * Note: This function can be called from two paths: The KVM_ARM_VCPU_INIT
 182  * ioctl or as part of handling a request issued by another VCPU in the PSCI
 183  * handling code.  In the first case, the VCPU will not be loaded, and in the
 184  * second case the VCPU will be loaded.  Because this function operates purely
 185  * on the memory-backed values of system registers, we want to do a full put if
 186  * we were loaded (handling a request) and load the values back at the end of
 187  * the function.  Otherwise we leave the state alone.  In both cases, we
 188  * disable preemption around the vcpu reset as we would otherwise race with
 189  * preempt notifiers which also call put/load.
 190  */
 191 void kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 192 {
 193         struct vcpu_reset_state reset_state;
 194         bool loaded;
 195         u32 pstate;
 196
 197         spin_lock(&vcpu->arch.mp_state_lock);
 198         reset_state = vcpu->arch.reset_state;
 199         vcpu->arch.reset_state.reset = false;
 200         spin_unlock(&vcpu->arch.mp_state_lock);
 201
 202         /* Reset PMU outside of the non-preemptible section */
 203         kvm_pmu_vcpu_reset(vcpu);
 204
 205         preempt_disable();
 206         loaded = (vcpu->cpu != -1);
 207         if (loaded)
 208                 kvm_arch_vcpu_put(vcpu);
 209
 210         if (!kvm_arm_vcpu_sve_finalized(vcpu)) {
 211                 if (vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE))
 212                         kvm_vcpu_enable_sve(vcpu);
 213         } else {
 214                 kvm_vcpu_reset_sve(vcpu);
 215         }
 216
 217         if (vcpu_has_feature(vcpu, KVM_ARM_VCPU_PTRAUTH_ADDRESS) ||
 218             vcpu_has_feature(vcpu, KVM_ARM_VCPU_PTRAUTH_GENERIC))
 219                 kvm_vcpu_enable_ptrauth(vcpu);
 220
 221         if (vcpu_el1_is_32bit(vcpu))
 222                 pstate = VCPU_RESET_PSTATE_SVC;
 223         else if (vcpu_has_nv(vcpu))
 224                 pstate = VCPU_RESET_PSTATE_EL2;
 225         else
 226                 pstate = VCPU_RESET_PSTATE_EL1;
 227
 228         /* Reset core registers */
 229         memset(vcpu_gp_regs(vcpu), 0, sizeof(*vcpu_gp_regs(vcpu)));
 230         memset(&vcpu->arch.ctxt.fp_regs, 0, sizeof(vcpu->arch.ctxt.fp_regs));
 231         vcpu->arch.ctxt.spsr_abt = 0;
 232         vcpu->arch.ctxt.spsr_und = 0;
 233         vcpu->arch.ctxt.spsr_irq = 0;
 234         vcpu->arch.ctxt.spsr_fiq = 0;
 235         vcpu_gp_regs(vcpu)->pstate = pstate;
 236
 237         /* Reset system registers */
 238         kvm_reset_sys_regs(vcpu);
 239
 240         /*
 241          * Additional reset state handling that PSCI may have imposed on us.
 242          * Must be done after all the sys_reg reset.
 243          */
 244         if (reset_state.reset) {
 245                 unsigned long target_pc = reset_state.pc;
 246
 247                 /* Gracefully handle Thumb2 entry point */
 248                 if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
 249                         target_pc &= ~1UL;
 250                         vcpu_set_thumb(vcpu);
 251                 }
 252
 253                 /* Propagate caller endianness */
 254                 if (reset_state.be)
 255                         kvm_vcpu_set_be(vcpu);
 256
 257                 *vcpu_pc(vcpu) = target_pc;
 258                 vcpu_set_reg(vcpu, 0, reset_state.r0);
 259         }
 260
 261         /* Reset timer */
 262         kvm_timer_vcpu_reset(vcpu);
 263
 264         if (loaded)
 265                 kvm_arch_vcpu_load(vcpu, smp_processor_id());
 266         preempt_enable();
 267 }
 268
 269 u32 get_kvm_ipa_limit(void)
 270 {
 271         return kvm_ipa_limit;
 272 }
 273
 274 int __init kvm_set_ipa_limit(void)
 275 {
 276         unsigned int parange;
 277         u64 mmfr0;
 278
 279         mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
 280         parange = cpuid_feature_extract_unsigned_field(mmfr0,
 281                                 ID_AA64MMFR0_EL1_PARANGE_SHIFT);
 282         /*
 283          * IPA size beyond 48 bits could not be supported
 284          * on either 4K or 16K page size. Hence let's cap
 285          * it to 48 bits, in case it's reported as larger
 286          * on the system.
 287          */
 288         if (PAGE_SIZE != SZ_64K)
 289                 parange = min(parange, (unsigned int)ID_AA64MMFR0_EL1_PARANGE_48);
 290
 291         /*
 292          * Check with ARMv8.5-GTG that our PAGE_SIZE is supported at
 293          * Stage-2. If not, things will stop very quickly.
 294          */
 295         switch (cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_EL1_TGRAN_2_SHIFT)) {
 296         case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_NONE:
 297                 kvm_err("PAGE_SIZE not supported at Stage-2, giving up\n");
 298                 return -EINVAL;
 299         case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_DEFAULT:
 300                 kvm_debug("PAGE_SIZE supported at Stage-2 (default)\n");
 301                 break;
 302         case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_MIN ... ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_MAX:
 303                 kvm_debug("PAGE_SIZE supported at Stage-2 (advertised)\n");
 304                 break;
 305         default:
 306                 kvm_err("Unsupported value for TGRAN_2, giving up\n");
 307                 return -EINVAL;
 308         }
 309
 310         kvm_ipa_limit = id_aa64mmfr0_parange_to_phys_shift(parange);
 311         kvm_info("IPA Size Limit: %d bits%s\n", kvm_ipa_limit,
 312                  ((kvm_ipa_limit < KVM_PHYS_SHIFT) ?
 313                   " (Reduced IPA size, limited VM/VMM compatibility)" : ""));
 314
 315         return 0;
 316 }