arch/arm64/kvm/hyp/sysreg-sr.c

   1 /*
   2  * Copyright (C) 2012-2015 - ARM Ltd
   3  * Author: Marc Zyngier <marc.zyngier@arm.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <linux/compiler.h>
  19 #include <linux/kvm_host.h>
  20
  21 #include <asm/kprobes.h>
  22 #include <asm/kvm_asm.h>
  23 #include <asm/kvm_emulate.h>
  24 #include <asm/kvm_hyp.h>
  25
  26 /*
  27  * Non-VHE: Both host and guest must save everything.
  28  *
  29  * VHE: Host and guest must save mdscr_el1 and sp_el0 (and the PC and pstate,
  30  * which are handled as part of the el2 return state) on every switch.
  31  * tpidr_el0 and tpidrro_el0 only need to be switched when going
  32  * to host userspace or a different VCPU.  EL1 registers only need to be
  33  * switched when potentially going to run a different VCPU.  The latter two
  34  * classes are handled as part of kvm_arch_vcpu_load and kvm_arch_vcpu_put.
  35  */
  36
  37 static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
  38 {
  39         ctxt->sys_regs[MDSCR_EL1]       = read_sysreg(mdscr_el1);
  40
  41         /*
  42          * The host arm64 Linux uses sp_el0 to point to 'current' and it must
  43          * therefore be saved/restored on every entry/exit to/from the guest.
  44          */
  45         ctxt->gp_regs.regs.sp           = read_sysreg(sp_el0);
  46 }
  47
  48 static void __hyp_text __sysreg_save_user_state(struct kvm_cpu_context *ctxt)
  49 {
  50         ctxt->sys_regs[TPIDR_EL0]       = read_sysreg(tpidr_el0);
  51         ctxt->sys_regs[TPIDRRO_EL0]     = read_sysreg(tpidrro_el0);
  52 }
  53
  54 static void __hyp_text __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
  55 {
  56         ctxt->sys_regs[MPIDR_EL1]       = read_sysreg(vmpidr_el2);
  57         ctxt->sys_regs[CSSELR_EL1]      = read_sysreg(csselr_el1);
  58         ctxt->sys_regs[SCTLR_EL1]       = read_sysreg_el1(sctlr);
  59         ctxt->sys_regs[ACTLR_EL1]       = read_sysreg(actlr_el1);
  60         ctxt->sys_regs[CPACR_EL1]       = read_sysreg_el1(cpacr);
  61         ctxt->sys_regs[TTBR0_EL1]       = read_sysreg_el1(ttbr0);
  62         ctxt->sys_regs[TTBR1_EL1]       = read_sysreg_el1(ttbr1);
  63         ctxt->sys_regs[TCR_EL1]         = read_sysreg_el1(tcr);
  64         ctxt->sys_regs[ESR_EL1]         = read_sysreg_el1(esr);
  65         ctxt->sys_regs[AFSR0_EL1]       = read_sysreg_el1(afsr0);
  66         ctxt->sys_regs[AFSR1_EL1]       = read_sysreg_el1(afsr1);
  67         ctxt->sys_regs[FAR_EL1]         = read_sysreg_el1(far);
  68         ctxt->sys_regs[MAIR_EL1]        = read_sysreg_el1(mair);
  69         ctxt->sys_regs[VBAR_EL1]        = read_sysreg_el1(vbar);
  70         ctxt->sys_regs[CONTEXTIDR_EL1]  = read_sysreg_el1(contextidr);
  71         ctxt->sys_regs[AMAIR_EL1]       = read_sysreg_el1(amair);
  72         ctxt->sys_regs[CNTKCTL_EL1]     = read_sysreg_el1(cntkctl);
  73         ctxt->sys_regs[PAR_EL1]         = read_sysreg(par_el1);
  74         ctxt->sys_regs[TPIDR_EL1]       = read_sysreg(tpidr_el1);
  75
  76         ctxt->gp_regs.sp_el1            = read_sysreg(sp_el1);
  77         ctxt->gp_regs.elr_el1           = read_sysreg_el1(elr);
  78         ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg_el1(spsr);
  79 }
  80
  81 static void __hyp_text __sysreg_save_el2_return_state(struct kvm_cpu_context *ctxt)
  82 {
  83         ctxt->gp_regs.regs.pc           = read_sysreg_el2(elr);
  84         ctxt->gp_regs.regs.pstate       = read_sysreg_el2(spsr);
  85
  86         if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN))
  87                 ctxt->sys_regs[DISR_EL1] = read_sysreg_s(SYS_VDISR_EL2);
  88 }
  89
  90 void __hyp_text __sysreg_save_state_nvhe(struct kvm_cpu_context *ctxt)
  91 {
  92         __sysreg_save_el1_state(ctxt);
  93         __sysreg_save_common_state(ctxt);
  94         __sysreg_save_user_state(ctxt);
  95         __sysreg_save_el2_return_state(ctxt);
  96 }
  97
  98 void sysreg_save_host_state_vhe(struct kvm_cpu_context *ctxt)
  99 {
 100         __sysreg_save_common_state(ctxt);
 101 }
 102 NOKPROBE_SYMBOL(sysreg_save_host_state_vhe);
 103
 104 void sysreg_save_guest_state_vhe(struct kvm_cpu_context *ctxt)
 105 {
 106         __sysreg_save_common_state(ctxt);
 107         __sysreg_save_el2_return_state(ctxt);
 108 }
 109 NOKPROBE_SYMBOL(sysreg_save_guest_state_vhe);
 110
 111 static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
 112 {
 113         write_sysreg(ctxt->sys_regs[MDSCR_EL1],   mdscr_el1);
 114
 115         /*
 116          * The host arm64 Linux uses sp_el0 to point to 'current' and it must
 117          * therefore be saved/restored on every entry/exit to/from the guest.
 118          */
 119         write_sysreg(ctxt->gp_regs.regs.sp,       sp_el0);
 120 }
 121
 122 static void __hyp_text __sysreg_restore_user_state(struct kvm_cpu_context *ctxt)
 123 {
 124         write_sysreg(ctxt->sys_regs[TPIDR_EL0],         tpidr_el0);
 125         write_sysreg(ctxt->sys_regs[TPIDRRO_EL0],       tpidrro_el0);
 126 }
 127
 128 static void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
 129 {
 130         write_sysreg(ctxt->sys_regs[MPIDR_EL1],         vmpidr_el2);
 131         write_sysreg(ctxt->sys_regs[CSSELR_EL1],        csselr_el1);
 132         write_sysreg_el1(ctxt->sys_regs[SCTLR_EL1],     sctlr);
 133         write_sysreg(ctxt->sys_regs[ACTLR_EL1],         actlr_el1);
 134         write_sysreg_el1(ctxt->sys_regs[CPACR_EL1],     cpacr);
 135         write_sysreg_el1(ctxt->sys_regs[TTBR0_EL1],     ttbr0);
 136         write_sysreg_el1(ctxt->sys_regs[TTBR1_EL1],     ttbr1);
 137         write_sysreg_el1(ctxt->sys_regs[TCR_EL1],       tcr);
 138         write_sysreg_el1(ctxt->sys_regs[ESR_EL1],       esr);
 139         write_sysreg_el1(ctxt->sys_regs[AFSR0_EL1],     afsr0);
 140         write_sysreg_el1(ctxt->sys_regs[AFSR1_EL1],     afsr1);
 141         write_sysreg_el1(ctxt->sys_regs[FAR_EL1],       far);
 142         write_sysreg_el1(ctxt->sys_regs[MAIR_EL1],      mair);
 143         write_sysreg_el1(ctxt->sys_regs[VBAR_EL1],      vbar);
 144         write_sysreg_el1(ctxt->sys_regs[CONTEXTIDR_EL1],contextidr);
 145         write_sysreg_el1(ctxt->sys_regs[AMAIR_EL1],     amair);
 146         write_sysreg_el1(ctxt->sys_regs[CNTKCTL_EL1],   cntkctl);
 147         write_sysreg(ctxt->sys_regs[PAR_EL1],           par_el1);
 148         write_sysreg(ctxt->sys_regs[TPIDR_EL1],         tpidr_el1);
 149
 150         write_sysreg(ctxt->gp_regs.sp_el1,              sp_el1);
 151         write_sysreg_el1(ctxt->gp_regs.elr_el1,         elr);
 152         write_sysreg_el1(ctxt->gp_regs.spsr[KVM_SPSR_EL1],spsr);
 153 }
 154
 155 static void __hyp_text
 156 __sysreg_restore_el2_return_state(struct kvm_cpu_context *ctxt)
 157 {
 158         write_sysreg_el2(ctxt->gp_regs.regs.pc,         elr);
 159         write_sysreg_el2(ctxt->gp_regs.regs.pstate,     spsr);
 160
 161         if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN))
 162                 write_sysreg_s(ctxt->sys_regs[DISR_EL1], SYS_VDISR_EL2);
 163 }
 164
 165 void __hyp_text __sysreg_restore_state_nvhe(struct kvm_cpu_context *ctxt)
 166 {
 167         __sysreg_restore_el1_state(ctxt);
 168         __sysreg_restore_common_state(ctxt);
 169         __sysreg_restore_user_state(ctxt);
 170         __sysreg_restore_el2_return_state(ctxt);
 171 }
 172
 173 void sysreg_restore_host_state_vhe(struct kvm_cpu_context *ctxt)
 174 {
 175         __sysreg_restore_common_state(ctxt);
 176 }
 177 NOKPROBE_SYMBOL(sysreg_restore_host_state_vhe);
 178
 179 void sysreg_restore_guest_state_vhe(struct kvm_cpu_context *ctxt)
 180 {
 181         __sysreg_restore_common_state(ctxt);
 182         __sysreg_restore_el2_return_state(ctxt);
 183 }
 184 NOKPROBE_SYMBOL(sysreg_restore_guest_state_vhe);
 185
 186 void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
 187 {
 188         u64 *spsr, *sysreg;
 189
 190         if (!vcpu_el1_is_32bit(vcpu))
 191                 return;
 192
 193         spsr = vcpu->arch.ctxt.gp_regs.spsr;
 194         sysreg = vcpu->arch.ctxt.sys_regs;
 195
 196         spsr[KVM_SPSR_ABT] = read_sysreg(spsr_abt);
 197         spsr[KVM_SPSR_UND] = read_sysreg(spsr_und);
 198         spsr[KVM_SPSR_IRQ] = read_sysreg(spsr_irq);
 199         spsr[KVM_SPSR_FIQ] = read_sysreg(spsr_fiq);
 200
 201         sysreg[DACR32_EL2] = read_sysreg(dacr32_el2);
 202         sysreg[IFSR32_EL2] = read_sysreg(ifsr32_el2);
 203
 204         if (has_vhe() || vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY)
 205                 sysreg[DBGVCR32_EL2] = read_sysreg(dbgvcr32_el2);
 206 }
 207
 208 void __hyp_text __sysreg32_restore_state(struct kvm_vcpu *vcpu)
 209 {
 210         u64 *spsr, *sysreg;
 211
 212         if (!vcpu_el1_is_32bit(vcpu))
 213                 return;
 214
 215         spsr = vcpu->arch.ctxt.gp_regs.spsr;
 216         sysreg = vcpu->arch.ctxt.sys_regs;
 217
 218         write_sysreg(spsr[KVM_SPSR_ABT], spsr_abt);
 219         write_sysreg(spsr[KVM_SPSR_UND], spsr_und);
 220         write_sysreg(spsr[KVM_SPSR_IRQ], spsr_irq);
 221         write_sysreg(spsr[KVM_SPSR_FIQ], spsr_fiq);
 222
 223         write_sysreg(sysreg[DACR32_EL2], dacr32_el2);
 224         write_sysreg(sysreg[IFSR32_EL2], ifsr32_el2);
 225
 226         if (has_vhe() || vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY)
 227                 write_sysreg(sysreg[DBGVCR32_EL2], dbgvcr32_el2);
 228 }
 229
 230 /**
 231  * kvm_vcpu_load_sysregs - Load guest system registers to the physical CPU
 232  *
 233  * @vcpu: The VCPU pointer
 234  *
 235  * Load system registers that do not affect the host's execution, for
 236  * example EL1 system registers on a VHE system where the host kernel
 237  * runs at EL2.  This function is called from KVM's vcpu_load() function
 238  * and loading system register state early avoids having to load them on
 239  * every entry to the VM.
 240  */
 241 void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu)
 242 {
 243         struct kvm_cpu_context *host_ctxt = vcpu->arch.host_cpu_context;
 244         struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
 245
 246         if (!has_vhe())
 247                 return;
 248
 249         __sysreg_save_user_state(host_ctxt);
 250
 251         /*
 252          * Load guest EL1 and user state
 253          *
 254          * We must restore the 32-bit state before the sysregs, thanks
 255          * to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
 256          */
 257         __sysreg32_restore_state(vcpu);
 258         __sysreg_restore_user_state(guest_ctxt);
 259         __sysreg_restore_el1_state(guest_ctxt);
 260
 261         vcpu->arch.sysregs_loaded_on_cpu = true;
 262
 263         activate_traps_vhe_load(vcpu);
 264 }
 265
 266 /**
 267  * kvm_vcpu_put_sysregs - Restore host system registers to the physical CPU
 268  *
 269  * @vcpu: The VCPU pointer
 270  *
 271  * Save guest system registers that do not affect the host's execution, for
 272  * example EL1 system registers on a VHE system where the host kernel
 273  * runs at EL2.  This function is called from KVM's vcpu_put() function
 274  * and deferring saving system register state until we're no longer running the
 275  * VCPU avoids having to save them on every exit from the VM.
 276  */
 277 void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu)
 278 {
 279         struct kvm_cpu_context *host_ctxt = vcpu->arch.host_cpu_context;
 280         struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
 281
 282         if (!has_vhe())
 283                 return;
 284
 285         deactivate_traps_vhe_put();
 286
 287         __sysreg_save_el1_state(guest_ctxt);
 288         __sysreg_save_user_state(guest_ctxt);
 289         __sysreg32_save_state(vcpu);
 290
 291         /* Restore host user state */
 292         __sysreg_restore_user_state(host_ctxt);
 293
 294         vcpu->arch.sysregs_loaded_on_cpu = false;
 295 }
 296
 297 void __hyp_text __kvm_enable_ssbs(void)
 298 {
 299         u64 tmp;
 300
 301         asm volatile(
 302         "mrs    %0, sctlr_el2\n"
 303         "orr    %0, %0, %1\n"
 304         "msr    sctlr_el2, %0"
 305         : "=&r" (tmp) : "L" (SCTLR_ELx_DSSBS));
 306 }