// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2021 Western Digital Corporation or its affiliates.
 *
 * Authors:
 *     Atish Patra <atish.patra@wdc.com>
 */

#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
#include <asm/sbi.h>
#include <asm/kvm_vcpu_timer.h>
#include <asm/kvm_vcpu_sbi.h>

static int kvm_sbi_ext_v01_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
                                   struct kvm_vcpu_sbi_return *retdata)
{
        ulong hmask;
        int i, ret = 0;
        u64 next_cycle;
        struct kvm_vcpu *rvcpu;
        struct kvm *kvm = vcpu->kvm;
        struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
        struct kvm_cpu_trap *utrap = retdata->utrap;
        unsigned long vmid;

        switch (cp->a7) {
        case SBI_EXT_0_1_CONSOLE_GETCHAR:
        case SBI_EXT_0_1_CONSOLE_PUTCHAR:
                /*
                 * The CONSOLE_GETCHAR/CONSOLE_PUTCHAR SBI calls cannot be
                 * handled in kernel so we forward these to user-space
                 */
                ret = kvm_riscv_vcpu_sbi_forward_handler(vcpu, run, retdata);
                break;
        case SBI_EXT_0_1_SET_TIMER:
#if __riscv_xlen == 32
                next_cycle = ((u64)cp->a1 << 32) | (u64)cp->a0;
#else
                next_cycle = (u64)cp->a0;
#endif
                ret = kvm_riscv_vcpu_timer_next_event(vcpu, next_cycle);
                break;
        case SBI_EXT_0_1_CLEAR_IPI:
                ret = kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_VS_SOFT);
                break;
        case SBI_EXT_0_1_SEND_IPI:
                if (cp->a0)
                        hmask = kvm_riscv_vcpu_unpriv_read(vcpu, false, cp->a0, utrap);
                else
                        hmask = (1UL << atomic_read(&kvm->online_vcpus)) - 1;
                if (utrap->scause)
                        break;

                for_each_set_bit(i, &hmask, BITS_PER_LONG) {
                        rvcpu = kvm_get_vcpu_by_id(vcpu->kvm, i);
                        ret = kvm_riscv_vcpu_set_interrupt(rvcpu, IRQ_VS_SOFT);
                        if (ret < 0)
                                break;
                }
                break;
        case SBI_EXT_0_1_SHUTDOWN:
                kvm_riscv_vcpu_sbi_system_reset(vcpu, run,
                                                KVM_SYSTEM_EVENT_SHUTDOWN, 0);
                retdata->uexit = true;
                break;
        case SBI_EXT_0_1_REMOTE_FENCE_I:
        case SBI_EXT_0_1_REMOTE_SFENCE_VMA:
        case SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID:
                if (cp->a0)
                        hmask = kvm_riscv_vcpu_unpriv_read(vcpu, false, cp->a0, utrap);
                else
                        hmask = (1UL << atomic_read(&kvm->online_vcpus)) - 1;
                if (utrap->scause)
                        break;

                if (cp->a7 == SBI_EXT_0_1_REMOTE_FENCE_I)
                        kvm_riscv_fence_i(vcpu->kvm, 0, hmask);
                else if (cp->a7 == SBI_EXT_0_1_REMOTE_SFENCE_VMA) {
                        vmid = READ_ONCE(vcpu->kvm->arch.vmid.vmid);
                        if (cp->a1 == 0 && cp->a2 == 0)
                                kvm_riscv_hfence_vvma_all(vcpu->kvm, 0, hmask, vmid);
                        else
                                kvm_riscv_hfence_vvma_gva(vcpu->kvm, 0, hmask, cp->a1,
                                                          cp->a2, PAGE_SHIFT, vmid);
                } else {
                        vmid = READ_ONCE(vcpu->kvm->arch.vmid.vmid);
                        if (cp->a1 == 0 && cp->a2 == 0)
                                kvm_riscv_hfence_vvma_asid_all(vcpu->kvm, 0, hmask,
                                                               cp->a3, vmid);
                        else
                                kvm_riscv_hfence_vvma_asid_gva(vcpu->kvm, 0, hmask,
                                                               cp->a1, cp->a2, PAGE_SHIFT,
                                                               cp->a3, vmid);
                }
                break;
        default:
                retdata->err_val = SBI_ERR_NOT_SUPPORTED;
                break;
        }

        return ret;
}

const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
        .extid_start = SBI_EXT_0_1_SET_TIMER,
        .extid_end = SBI_EXT_0_1_SHUTDOWN,
        .handler = kvm_sbi_ext_v01_handler,
};