/*
 * 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/irqchip/arm-gic-v3.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <kvm/arm_vgic.h>
#include <asm/kvm_mmu.h>
#include <asm/kvm_asm.h>

#include "vgic.h"

void vgic_v3_process_maintenance(struct kvm_vcpu *vcpu)
{
        struct vgic_v3_cpu_if *cpuif = &vcpu->arch.vgic_cpu.vgic_v3;
        u32 model = vcpu->kvm->arch.vgic.vgic_model;

        if (cpuif->vgic_misr & ICH_MISR_EOI) {
                unsigned long eisr_bmap = cpuif->vgic_eisr;
                int lr;

                for_each_set_bit(lr, &eisr_bmap, kvm_vgic_global_state.nr_lr) {
                        u32 intid;
                        u64 val = cpuif->vgic_lr[lr];

                        if (model == KVM_DEV_TYPE_ARM_VGIC_V3)
                                intid = val & ICH_LR_VIRTUAL_ID_MASK;
                        else
                                intid = val & GICH_LR_VIRTUALID;

                        WARN_ON(cpuif->vgic_lr[lr] & ICH_LR_STATE);

                        /* Only SPIs require notification */
                        if (vgic_valid_spi(vcpu->kvm, intid))
                                kvm_notify_acked_irq(vcpu->kvm, 0,
                                                     intid - VGIC_NR_PRIVATE_IRQS);
                }

                /*
                 * In the next iterations of the vcpu loop, if we sync
                 * the vgic state after flushing it, but before
                 * entering the guest (this happens for pending
                 * signals and vmid rollovers), then make sure we
                 * don't pick up any old maintenance interrupts here.
                 */
                cpuif->vgic_eisr = 0;
        }

        cpuif->vgic_hcr &= ~ICH_HCR_UIE;
}

void vgic_v3_set_underflow(struct kvm_vcpu *vcpu)
{
        struct vgic_v3_cpu_if *cpuif = &vcpu->arch.vgic_cpu.vgic_v3;

        cpuif->vgic_hcr |= ICH_HCR_UIE;
}

void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
{
        struct vgic_v3_cpu_if *cpuif = &vcpu->arch.vgic_cpu.vgic_v3;
        u32 model = vcpu->kvm->arch.vgic.vgic_model;
        int lr;

        for (lr = 0; lr < vcpu->arch.vgic_cpu.used_lrs; lr++) {
                u64 val = cpuif->vgic_lr[lr];
                u32 intid;
                struct vgic_irq *irq;

                if (model == KVM_DEV_TYPE_ARM_VGIC_V3)
                        intid = val & ICH_LR_VIRTUAL_ID_MASK;
                else
                        intid = val & GICH_LR_VIRTUALID;
                irq = vgic_get_irq(vcpu->kvm, vcpu, intid);
                if (!irq)       /* An LPI could have been unmapped. */
                        continue;

                spin_lock(&irq->irq_lock);

                /* Always preserve the active bit */
                irq->active = !!(val & ICH_LR_ACTIVE_BIT);

                /* Edge is the only case where we preserve the pending bit */
                if (irq->config == VGIC_CONFIG_EDGE &&
                    (val & ICH_LR_PENDING_BIT)) {
                        irq->pending = true;

                        if (vgic_irq_is_sgi(intid) &&
                            model == KVM_DEV_TYPE_ARM_VGIC_V2) {
                                u32 cpuid = val & GICH_LR_PHYSID_CPUID;

                                cpuid >>= GICH_LR_PHYSID_CPUID_SHIFT;
                                irq->source |= (1 << cpuid);
                        }
                }

                /*
                 * Clear soft pending state when level irqs have been acked.
                 * Always regenerate the pending state.
                 */
                if (irq->config == VGIC_CONFIG_LEVEL) {
                        if (!(val & ICH_LR_PENDING_BIT))
                                irq->soft_pending = false;

                        irq->pending = irq->line_level || irq->soft_pending;
                }

                spin_unlock(&irq->irq_lock);
                vgic_put_irq(vcpu->kvm, irq);
        }
}

/* Requires the irq to be locked already */
void vgic_v3_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr)
{
        u32 model = vcpu->kvm->arch.vgic.vgic_model;
        u64 val = irq->intid;

        if (irq->pending) {
                val |= ICH_LR_PENDING_BIT;

                if (irq->config == VGIC_CONFIG_EDGE)
                        irq->pending = false;

                if (vgic_irq_is_sgi(irq->intid) &&
                    model == KVM_DEV_TYPE_ARM_VGIC_V2) {
                        u32 src = ffs(irq->source);

                        BUG_ON(!src);
                        val |= (src - 1) << GICH_LR_PHYSID_CPUID_SHIFT;
                        irq->source &= ~(1 << (src - 1));
                        if (irq->source)
                                irq->pending = true;
                }
        }

        if (irq->active)
                val |= ICH_LR_ACTIVE_BIT;

        if (irq->hw) {
                val |= ICH_LR_HW;
                val |= ((u64)irq->hwintid) << ICH_LR_PHYS_ID_SHIFT;
        } else {
                if (irq->config == VGIC_CONFIG_LEVEL)
                        val |= ICH_LR_EOI;
        }

        /*
         * We currently only support Group1 interrupts, which is a
         * known defect. This needs to be addressed at some point.
         */
        if (model == KVM_DEV_TYPE_ARM_VGIC_V3)
                val |= ICH_LR_GROUP;

        val |= (u64)irq->priority << ICH_LR_PRIORITY_SHIFT;

        vcpu->arch.vgic_cpu.vgic_v3.vgic_lr[lr] = val;
}

void vgic_v3_clear_lr(struct kvm_vcpu *vcpu, int lr)
{
        vcpu->arch.vgic_cpu.vgic_v3.vgic_lr[lr] = 0;
}

void vgic_v3_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
{
        u32 vmcr;

        vmcr  = (vmcrp->ctlr << ICH_VMCR_CTLR_SHIFT) & ICH_VMCR_CTLR_MASK;
        vmcr |= (vmcrp->abpr << ICH_VMCR_BPR1_SHIFT) & ICH_VMCR_BPR1_MASK;
        vmcr |= (vmcrp->bpr << ICH_VMCR_BPR0_SHIFT) & ICH_VMCR_BPR0_MASK;
        vmcr |= (vmcrp->pmr << ICH_VMCR_PMR_SHIFT) & ICH_VMCR_PMR_MASK;

        vcpu->arch.vgic_cpu.vgic_v3.vgic_vmcr = vmcr;
}

void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
{
        u32 vmcr = vcpu->arch.vgic_cpu.vgic_v3.vgic_vmcr;

        vmcrp->ctlr = (vmcr & ICH_VMCR_CTLR_MASK) >> ICH_VMCR_CTLR_SHIFT;
        vmcrp->abpr = (vmcr & ICH_VMCR_BPR1_MASK) >> ICH_VMCR_BPR1_SHIFT;
        vmcrp->bpr  = (vmcr & ICH_VMCR_BPR0_MASK) >> ICH_VMCR_BPR0_SHIFT;
        vmcrp->pmr  = (vmcr & ICH_VMCR_PMR_MASK) >> ICH_VMCR_PMR_SHIFT;
}

#define INITIAL_PENDBASER_VALUE                                           \
        (GIC_BASER_CACHEABILITY(GICR_PENDBASER, INNER, RaWb)            | \
        GIC_BASER_CACHEABILITY(GICR_PENDBASER, OUTER, SameAsInner)      | \
        GIC_BASER_SHAREABILITY(GICR_PENDBASER, InnerShareable))

void vgic_v3_enable(struct kvm_vcpu *vcpu)
{
        struct vgic_v3_cpu_if *vgic_v3 = &vcpu->arch.vgic_cpu.vgic_v3;

        /*
         * By forcing VMCR to zero, the GIC will restore the binary
         * points to their reset values. Anything else resets to zero
         * anyway.
         */
        vgic_v3->vgic_vmcr = 0;
        vgic_v3->vgic_elrsr = ~0;

        /*
         * If we are emulating a GICv3, we do it in an non-GICv2-compatible
         * way, so we force SRE to 1 to demonstrate this to the guest.
         * This goes with the spec allowing the value to be RAO/WI.
         */
        if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
                vgic_v3->vgic_sre = ICC_SRE_EL1_SRE;
                vcpu->arch.vgic_cpu.pendbaser = INITIAL_PENDBASER_VALUE;
        } else {
                vgic_v3->vgic_sre = 0;
        }

        /* Get the show on the road... */
        vgic_v3->vgic_hcr = ICH_HCR_EN;
}

/* check for overlapping regions and for regions crossing the end of memory */
static bool vgic_v3_check_base(struct kvm *kvm)
{
        struct vgic_dist *d = &kvm->arch.vgic;
        gpa_t redist_size = KVM_VGIC_V3_REDIST_SIZE;

        redist_size *= atomic_read(&kvm->online_vcpus);

        if (d->vgic_dist_base + KVM_VGIC_V3_DIST_SIZE < d->vgic_dist_base)
                return false;
        if (d->vgic_redist_base + redist_size < d->vgic_redist_base)
                return false;

        if (d->vgic_dist_base + KVM_VGIC_V3_DIST_SIZE <= d->vgic_redist_base)
                return true;
        if (d->vgic_redist_base + redist_size <= d->vgic_dist_base)
                return true;

        return false;
}

int vgic_v3_map_resources(struct kvm *kvm)
{
        int ret = 0;
        struct vgic_dist *dist = &kvm->arch.vgic;

        if (vgic_ready(kvm))
                goto out;

        if (IS_VGIC_ADDR_UNDEF(dist->vgic_dist_base) ||
            IS_VGIC_ADDR_UNDEF(dist->vgic_redist_base)) {
                kvm_err("Need to set vgic distributor addresses first\n");
                ret = -ENXIO;
                goto out;
        }

        if (!vgic_v3_check_base(kvm)) {
                kvm_err("VGIC redist and dist frames overlap\n");
                ret = -EINVAL;
                goto out;
        }

        /*
         * For a VGICv3 we require the userland to explicitly initialize
         * the VGIC before we need to use it.
         */
        if (!vgic_initialized(kvm)) {
                ret = -EBUSY;
                goto out;
        }

        ret = vgic_register_dist_iodev(kvm, dist->vgic_dist_base, VGIC_V3);
        if (ret) {
                kvm_err("Unable to register VGICv3 dist MMIO regions\n");
                goto out;
        }

        ret = vgic_register_redist_iodevs(kvm, dist->vgic_redist_base);
        if (ret) {
                kvm_err("Unable to register VGICv3 redist MMIO regions\n");
                goto out;
        }

        if (vgic_has_its(kvm)) {
                ret = vgic_register_its_iodevs(kvm);
                if (ret) {
                        kvm_err("Unable to register VGIC ITS MMIO regions\n");
                        goto out;
                }
        }

        dist->ready = true;

out:
        if (ret)
                kvm_vgic_destroy(kvm);
        return ret;
}

/**
 * vgic_v3_probe - probe for a GICv3 compatible interrupt controller in DT
 * @node:       pointer to the DT node
 *
 * Returns 0 if a GICv3 has been found, returns an error code otherwise
 */
int vgic_v3_probe(const struct gic_kvm_info *info)
{
        u32 ich_vtr_el2 = kvm_call_hyp(__vgic_v3_get_ich_vtr_el2);
        int ret;

        /*
         * The ListRegs field is 5 bits, but there is a architectural
         * maximum of 16 list registers. Just ignore bit 4...
         */
        kvm_vgic_global_state.nr_lr = (ich_vtr_el2 & 0xf) + 1;
        kvm_vgic_global_state.can_emulate_gicv2 = false;

        if (!info->vcpu.start) {
                kvm_info("GICv3: no GICV resource entry\n");
                kvm_vgic_global_state.vcpu_base = 0;
        } else if (!PAGE_ALIGNED(info->vcpu.start)) {
                pr_warn("GICV physical address 0x%llx not page aligned\n",
                        (unsigned long long)info->vcpu.start);
                kvm_vgic_global_state.vcpu_base = 0;
        } else if (!PAGE_ALIGNED(resource_size(&info->vcpu))) {
                pr_warn("GICV size 0x%llx not a multiple of page size 0x%lx\n",
                        (unsigned long long)resource_size(&info->vcpu),
                        PAGE_SIZE);
                kvm_vgic_global_state.vcpu_base = 0;
        } else {
                kvm_vgic_global_state.vcpu_base = info->vcpu.start;
                kvm_vgic_global_state.can_emulate_gicv2 = true;
                ret = kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V2);
                if (ret) {
                        kvm_err("Cannot register GICv2 KVM device.\n");
                        return ret;
                }
                kvm_info("vgic-v2@%llx\n", info->vcpu.start);
        }
        ret = kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V3);
        if (ret) {
                kvm_err("Cannot register GICv3 KVM device.\n");
                kvm_unregister_device_ops(KVM_DEV_TYPE_ARM_VGIC_V2);
                return ret;
        }

        if (kvm_vgic_global_state.vcpu_base == 0)
                kvm_info("disabling GICv2 emulation\n");

        kvm_vgic_global_state.vctrl_base = NULL;
        kvm_vgic_global_state.type = VGIC_V3;
        kvm_vgic_global_state.max_gic_vcpus = VGIC_V3_MAX_CPUS;

        return 0;
}