Merge branches 'clk-optional', 'clk-devm-clkdev-register', 'clk-allwinner', 'clk...

[thirdparty/kernel/stable.git] / arch / arm64 / kvm / hyp / switch.c

/*
 * Copyright (C) 2015 - ARM Ltd
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/arm-smccc.h>
#include <linux/types.h>
#include <linux/jump_label.h>
#include <uapi/linux/psci.h>

#include <kvm/arm_psci.h>

#include <asm/cpufeature.h>
#include <asm/kprobes.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_host.h>
#include <asm/kvm_hyp.h>
#include <asm/kvm_mmu.h>
#include <asm/fpsimd.h>
#include <asm/debug-monitors.h>
#include <asm/processor.h>
#include <asm/thread_info.h>

/* Check whether the FP regs were dirtied while in the host-side run loop: */
static bool __hyp_text update_fp_enabled(struct kvm_vcpu *vcpu)
{
        if (vcpu->arch.host_thread_info->flags & _TIF_FOREIGN_FPSTATE)
                vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED |
                                      KVM_ARM64_FP_HOST);

        return !!(vcpu->arch.flags & KVM_ARM64_FP_ENABLED);
}

/* Save the 32-bit only FPSIMD system register state */
static void __hyp_text __fpsimd_save_fpexc32(struct kvm_vcpu *vcpu)
{
        if (!vcpu_el1_is_32bit(vcpu))
                return;

        vcpu->arch.ctxt.sys_regs[FPEXC32_EL2] = read_sysreg(fpexc32_el2);
}

static void __hyp_text __activate_traps_fpsimd32(struct kvm_vcpu *vcpu)
{
        /*
         * We are about to set CPTR_EL2.TFP to trap all floating point
         * register accesses to EL2, however, the ARM ARM clearly states that
         * traps are only taken to EL2 if the operation would not otherwise
         * trap to EL1.  Therefore, always make sure that for 32-bit guests,
         * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit.
         * If FP/ASIMD is not implemented, FPEXC is UNDEFINED and any access to
         * it will cause an exception.
         */
        if (vcpu_el1_is_32bit(vcpu) && system_supports_fpsimd()) {
                write_sysreg(1 << 30, fpexc32_el2);
                isb();
        }
}

static void __hyp_text __activate_traps_common(struct kvm_vcpu *vcpu)
{
        /* Trap on AArch32 cp15 c15 (impdef sysregs) accesses (EL1 or EL0) */
        write_sysreg(1 << 15, hstr_el2);

        /*
         * Make sure we trap PMU access from EL0 to EL2. Also sanitize
         * PMSELR_EL0 to make sure it never contains the cycle
         * counter, which could make a PMXEVCNTR_EL0 access UNDEF at
         * EL1 instead of being trapped to EL2.
         */
        write_sysreg(0, pmselr_el0);
        write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0);
        write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
}

static void __hyp_text __deactivate_traps_common(void)
{
        write_sysreg(0, hstr_el2);
        write_sysreg(0, pmuserenr_el0);
}

static void activate_traps_vhe(struct kvm_vcpu *vcpu)
{
        u64 val;

        val = read_sysreg(cpacr_el1);
        val |= CPACR_EL1_TTA;
        val &= ~CPACR_EL1_ZEN;
        if (!update_fp_enabled(vcpu)) {
                val &= ~CPACR_EL1_FPEN;
                __activate_traps_fpsimd32(vcpu);
        }

        write_sysreg(val, cpacr_el1);

        write_sysreg(kvm_get_hyp_vector(), vbar_el1);
}
NOKPROBE_SYMBOL(activate_traps_vhe);

static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu)
{
        u64 val;

        __activate_traps_common(vcpu);

        val = CPTR_EL2_DEFAULT;
        val |= CPTR_EL2_TTA | CPTR_EL2_TZ;
        if (!update_fp_enabled(vcpu)) {
                val |= CPTR_EL2_TFP;
                __activate_traps_fpsimd32(vcpu);
        }

        write_sysreg(val, cptr_el2);
}

static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
{
        u64 hcr = vcpu->arch.hcr_el2;

        write_sysreg(hcr, hcr_el2);

        if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN) && (hcr & HCR_VSE))
                write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2);

        if (has_vhe())
                activate_traps_vhe(vcpu);
        else
                __activate_traps_nvhe(vcpu);
}

static void deactivate_traps_vhe(void)
{
        extern char vectors[];  /* kernel exception vectors */
        write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);

        /*
         * ARM erratum 1165522 requires the actual execution of the above
         * before we can switch to the EL2/EL0 translation regime used by
         * the host.
         */
        asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_1165522));

        write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1);
        write_sysreg(vectors, vbar_el1);
}
NOKPROBE_SYMBOL(deactivate_traps_vhe);

static void __hyp_text __deactivate_traps_nvhe(void)
{
        u64 mdcr_el2 = read_sysreg(mdcr_el2);

        __deactivate_traps_common();

        mdcr_el2 &= MDCR_EL2_HPMN_MASK;
        mdcr_el2 |= MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT;

        write_sysreg(mdcr_el2, mdcr_el2);
        write_sysreg(HCR_HOST_NVHE_FLAGS, hcr_el2);
        write_sysreg(CPTR_EL2_DEFAULT, cptr_el2);
}

static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu)
{
        /*
         * If we pended a virtual abort, preserve it until it gets
         * cleared. See D1.14.3 (Virtual Interrupts) for details, but
         * the crucial bit is "On taking a vSError interrupt,
         * HCR_EL2.VSE is cleared to 0."
         */
        if (vcpu->arch.hcr_el2 & HCR_VSE)
                vcpu->arch.hcr_el2 = read_sysreg(hcr_el2);

        if (has_vhe())
                deactivate_traps_vhe();
        else
                __deactivate_traps_nvhe();
}

void activate_traps_vhe_load(struct kvm_vcpu *vcpu)
{
        __activate_traps_common(vcpu);
}

void deactivate_traps_vhe_put(void)
{
        u64 mdcr_el2 = read_sysreg(mdcr_el2);

        mdcr_el2 &= MDCR_EL2_HPMN_MASK |
                    MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT |
                    MDCR_EL2_TPMS;

        write_sysreg(mdcr_el2, mdcr_el2);

        __deactivate_traps_common();
}

static void __hyp_text __activate_vm(struct kvm *kvm)
{
        __load_guest_stage2(kvm);
}

static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu)
{
        write_sysreg(0, vttbr_el2);
}

/* Save VGICv3 state on non-VHE systems */
static void __hyp_text __hyp_vgic_save_state(struct kvm_vcpu *vcpu)
{
        if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
                __vgic_v3_save_state(vcpu);
                __vgic_v3_deactivate_traps(vcpu);
        }
}

/* Restore VGICv3 state on non_VEH systems */
static void __hyp_text __hyp_vgic_restore_state(struct kvm_vcpu *vcpu)
{
        if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
                __vgic_v3_activate_traps(vcpu);
                __vgic_v3_restore_state(vcpu);
        }
}

static bool __hyp_text __true_value(void)
{
        return true;
}

static bool __hyp_text __false_value(void)
{
        return false;
}

static hyp_alternate_select(__check_arm_834220,
                            __false_value, __true_value,
                            ARM64_WORKAROUND_834220);

static bool __hyp_text __translate_far_to_hpfar(u64 far, u64 *hpfar)
{
        u64 par, tmp;

        /*
         * Resolve the IPA the hard way using the guest VA.
         *
         * Stage-1 translation already validated the memory access
         * rights. As such, we can use the EL1 translation regime, and
         * don't have to distinguish between EL0 and EL1 access.
         *
         * We do need to save/restore PAR_EL1 though, as we haven't
         * saved the guest context yet, and we may return early...
         */
        par = read_sysreg(par_el1);
        asm volatile("at s1e1r, %0" : : "r" (far));
        isb();

        tmp = read_sysreg(par_el1);
        write_sysreg(par, par_el1);

        if (unlikely(tmp & 1))
                return false; /* Translation failed, back to guest */

        /* Convert PAR to HPFAR format */
        *hpfar = PAR_TO_HPFAR(tmp);
        return true;
}

static bool __hyp_text __populate_fault_info(struct kvm_vcpu *vcpu)
{
        u8 ec;
        u64 esr;
        u64 hpfar, far;

        esr = vcpu->arch.fault.esr_el2;
        ec = ESR_ELx_EC(esr);

        if (ec != ESR_ELx_EC_DABT_LOW && ec != ESR_ELx_EC_IABT_LOW)
                return true;

        far = read_sysreg_el2(far);

        /*
         * The HPFAR can be invalid if the stage 2 fault did not
         * happen during a stage 1 page table walk (the ESR_EL2.S1PTW
         * bit is clear) and one of the two following cases are true:
         *   1. The fault was due to a permission fault
         *   2. The processor carries errata 834220
         *
         * Therefore, for all non S1PTW faults where we either have a
         * permission fault or the errata workaround is enabled, we
         * resolve the IPA using the AT instruction.
         */
        if (!(esr & ESR_ELx_S1PTW) &&
            (__check_arm_834220()() || (esr & ESR_ELx_FSC_TYPE) == FSC_PERM)) {
                if (!__translate_far_to_hpfar(far, &hpfar))
                        return false;
        } else {
                hpfar = read_sysreg(hpfar_el2);
        }

        vcpu->arch.fault.far_el2 = far;
        vcpu->arch.fault.hpfar_el2 = hpfar;
        return true;
}

static bool __hyp_text __hyp_switch_fpsimd(struct kvm_vcpu *vcpu)
{
        struct user_fpsimd_state *host_fpsimd = vcpu->arch.host_fpsimd_state;

        if (has_vhe())
                write_sysreg(read_sysreg(cpacr_el1) | CPACR_EL1_FPEN,
                             cpacr_el1);
        else
                write_sysreg(read_sysreg(cptr_el2) & ~(u64)CPTR_EL2_TFP,
                             cptr_el2);

        isb();

        if (vcpu->arch.flags & KVM_ARM64_FP_HOST) {
                /*
                 * In the SVE case, VHE is assumed: it is enforced by
                 * Kconfig and kvm_arch_init().
                 */
                if (system_supports_sve() &&
                    (vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE)) {
                        struct thread_struct *thread = container_of(
                                host_fpsimd,
                                struct thread_struct, uw.fpsimd_state);

                        sve_save_state(sve_pffr(thread), &host_fpsimd->fpsr);
                } else {
                        __fpsimd_save_state(host_fpsimd);
                }

                vcpu->arch.flags &= ~KVM_ARM64_FP_HOST;
        }

        __fpsimd_restore_state(&vcpu->arch.ctxt.gp_regs.fp_regs);

        /* Skip restoring fpexc32 for AArch64 guests */
        if (!(read_sysreg(hcr_el2) & HCR_RW))
                write_sysreg(vcpu->arch.ctxt.sys_regs[FPEXC32_EL2],
                             fpexc32_el2);

        vcpu->arch.flags |= KVM_ARM64_FP_ENABLED;

        return true;
}

/*
 * Return true when we were able to fixup the guest exit and should return to
 * the guest, false when we should restore the host state and return to the
 * main run loop.
 */
static bool __hyp_text fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
{
        if (ARM_EXCEPTION_CODE(*exit_code) != ARM_EXCEPTION_IRQ)
                vcpu->arch.fault.esr_el2 = read_sysreg_el2(esr);

        /*
         * We're using the raw exception code in order to only process
         * the trap if no SError is pending. We will come back to the
         * same PC once the SError has been injected, and replay the
         * trapping instruction.
         */
        if (*exit_code != ARM_EXCEPTION_TRAP)
                goto exit;

        /*
         * We trap the first access to the FP/SIMD to save the host context
         * and restore the guest context lazily.
         * If FP/SIMD is not implemented, handle the trap and inject an
         * undefined instruction exception to the guest.
         */
        if (system_supports_fpsimd() &&
            kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_FP_ASIMD)
                return __hyp_switch_fpsimd(vcpu);

        if (!__populate_fault_info(vcpu))
                return true;

        if (static_branch_unlikely(&vgic_v2_cpuif_trap)) {
                bool valid;

                valid = kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_DABT_LOW &&
                        kvm_vcpu_trap_get_fault_type(vcpu) == FSC_FAULT &&
                        kvm_vcpu_dabt_isvalid(vcpu) &&
                        !kvm_vcpu_dabt_isextabt(vcpu) &&
                        !kvm_vcpu_dabt_iss1tw(vcpu);

                if (valid) {
                        int ret = __vgic_v2_perform_cpuif_access(vcpu);

                        if (ret == 1)
                                return true;

                        /* Promote an illegal access to an SError.*/
                        if (ret == -1)
                                *exit_code = ARM_EXCEPTION_EL1_SERROR;

                        goto exit;
                }
        }

        if (static_branch_unlikely(&vgic_v3_cpuif_trap) &&
            (kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_SYS64 ||
             kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_CP15_32)) {
                int ret = __vgic_v3_perform_cpuif_access(vcpu);

                if (ret == 1)
                        return true;
        }

exit:
        /* Return to the host kernel and handle the exit */
        return false;
}

static inline bool __hyp_text __needs_ssbd_off(struct kvm_vcpu *vcpu)
{
        if (!cpus_have_const_cap(ARM64_SSBD))
                return false;

        return !(vcpu->arch.workaround_flags & VCPU_WORKAROUND_2_FLAG);
}

static void __hyp_text __set_guest_arch_workaround_state(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_ARM64_SSBD
        /*
         * The host runs with the workaround always present. If the
         * guest wants it disabled, so be it...
         */
        if (__needs_ssbd_off(vcpu) &&
            __hyp_this_cpu_read(arm64_ssbd_callback_required))
                arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_2, 0, NULL);
#endif
}

static void __hyp_text __set_host_arch_workaround_state(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_ARM64_SSBD
        /*
         * If the guest has disabled the workaround, bring it back on.
         */
        if (__needs_ssbd_off(vcpu) &&
            __hyp_this_cpu_read(arm64_ssbd_callback_required))
                arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_2, 1, NULL);
#endif
}

/* Switch to the guest for VHE systems running in EL2 */
int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
{
        struct kvm_cpu_context *host_ctxt;
        struct kvm_cpu_context *guest_ctxt;
        u64 exit_code;

        host_ctxt = vcpu->arch.host_cpu_context;
        host_ctxt->__hyp_running_vcpu = vcpu;
        guest_ctxt = &vcpu->arch.ctxt;

        sysreg_save_host_state_vhe(host_ctxt);

        /*
         * ARM erratum 1165522 requires us to configure both stage 1 and
         * stage 2 translation for the guest context before we clear
         * HCR_EL2.TGE.
         *
         * We have already configured the guest's stage 1 translation in
         * kvm_vcpu_load_sysregs above.  We must now call __activate_vm
         * before __activate_traps, because __activate_vm configures
         * stage 2 translation, and __activate_traps clear HCR_EL2.TGE
         * (among other things).
         */
        __activate_vm(vcpu->kvm);
        __activate_traps(vcpu);

        sysreg_restore_guest_state_vhe(guest_ctxt);
        __debug_switch_to_guest(vcpu);

        __set_guest_arch_workaround_state(vcpu);

        do {
                /* Jump in the fire! */
                exit_code = __guest_enter(vcpu, host_ctxt);

                /* And we're baaack! */
        } while (fixup_guest_exit(vcpu, &exit_code));

        __set_host_arch_workaround_state(vcpu);

        sysreg_save_guest_state_vhe(guest_ctxt);

        __deactivate_traps(vcpu);

        sysreg_restore_host_state_vhe(host_ctxt);

        if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED)
                __fpsimd_save_fpexc32(vcpu);

        __debug_switch_to_host(vcpu);

        return exit_code;
}
NOKPROBE_SYMBOL(kvm_vcpu_run_vhe);

/* Switch to the guest for legacy non-VHE systems */
int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
{
        struct kvm_cpu_context *host_ctxt;
        struct kvm_cpu_context *guest_ctxt;
        u64 exit_code;

        vcpu = kern_hyp_va(vcpu);

        host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
        host_ctxt->__hyp_running_vcpu = vcpu;
        guest_ctxt = &vcpu->arch.ctxt;

        __sysreg_save_state_nvhe(host_ctxt);

        __activate_vm(kern_hyp_va(vcpu->kvm));
        __activate_traps(vcpu);

        __hyp_vgic_restore_state(vcpu);
        __timer_enable_traps(vcpu);

        /*
         * We must restore the 32-bit state before the sysregs, thanks
         * to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
         */
        __sysreg32_restore_state(vcpu);
        __sysreg_restore_state_nvhe(guest_ctxt);
        __debug_switch_to_guest(vcpu);

        __set_guest_arch_workaround_state(vcpu);

        do {
                /* Jump in the fire! */
                exit_code = __guest_enter(vcpu, host_ctxt);

                /* And we're baaack! */
        } while (fixup_guest_exit(vcpu, &exit_code));

        __set_host_arch_workaround_state(vcpu);

        __sysreg_save_state_nvhe(guest_ctxt);
        __sysreg32_save_state(vcpu);
        __timer_disable_traps(vcpu);
        __hyp_vgic_save_state(vcpu);

        __deactivate_traps(vcpu);
        __deactivate_vm(vcpu);

        __sysreg_restore_state_nvhe(host_ctxt);

        if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED)
                __fpsimd_save_fpexc32(vcpu);

        /*
         * This must come after restoring the host sysregs, since a non-VHE
         * system may enable SPE here and make use of the TTBRs.
         */
        __debug_switch_to_host(vcpu);

        return exit_code;
}

static const char __hyp_panic_string[] = "HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n";

static void __hyp_text __hyp_call_panic_nvhe(u64 spsr, u64 elr, u64 par,
                                             struct kvm_cpu_context *__host_ctxt)
{
        struct kvm_vcpu *vcpu;
        unsigned long str_va;

        vcpu = __host_ctxt->__hyp_running_vcpu;

        if (read_sysreg(vttbr_el2)) {
                __timer_disable_traps(vcpu);
                __deactivate_traps(vcpu);
                __deactivate_vm(vcpu);
                __sysreg_restore_state_nvhe(__host_ctxt);
        }

        /*
         * Force the panic string to be loaded from the literal pool,
         * making sure it is a kernel address and not a PC-relative
         * reference.
         */
        asm volatile("ldr %0, =__hyp_panic_string" : "=r" (str_va));

        __hyp_do_panic(str_va,
                       spsr,  elr,
                       read_sysreg(esr_el2),   read_sysreg_el2(far),
                       read_sysreg(hpfar_el2), par, vcpu);
}

static void __hyp_call_panic_vhe(u64 spsr, u64 elr, u64 par,
                                 struct kvm_cpu_context *host_ctxt)
{
        struct kvm_vcpu *vcpu;
        vcpu = host_ctxt->__hyp_running_vcpu;

        __deactivate_traps(vcpu);
        sysreg_restore_host_state_vhe(host_ctxt);

        panic(__hyp_panic_string,
              spsr,  elr,
              read_sysreg_el2(esr),   read_sysreg_el2(far),
              read_sysreg(hpfar_el2), par, vcpu);
}
NOKPROBE_SYMBOL(__hyp_call_panic_vhe);

void __hyp_text __noreturn hyp_panic(struct kvm_cpu_context *host_ctxt)
{
        u64 spsr = read_sysreg_el2(spsr);
        u64 elr = read_sysreg_el2(elr);
        u64 par = read_sysreg(par_el1);

        if (!has_vhe())
                __hyp_call_panic_nvhe(spsr, elr, par, host_ctxt);
        else
                __hyp_call_panic_vhe(spsr, elr, par, host_ctxt);

        unreachable();
}