/*
 * Copyright (c) 2006, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 * Copyright (C) 2006-2008 Intel Corporation
 * Copyright IBM Corporation, 2008
 * Author: Allen M. Kay <allen.m.kay@intel.com>
 * Author: Weidong Han <weidong.han@intel.com>
 * Author: Ben-Ami Yassour <benami@il.ibm.com>
 */

#include <linux/list.h>
#include <linux/kvm_host.h>
#include <linux/pci.h>
#include <linux/dmar.h>
#include <linux/iommu.h>
#include <linux/intel-iommu.h>

static int kvm_iommu_unmap_memslots(struct kvm *kvm);
static void kvm_iommu_put_pages(struct kvm *kvm,
                                gfn_t base_gfn, unsigned long npages);

int kvm_iommu_map_pages(struct kvm *kvm,
                        gfn_t base_gfn, unsigned long npages)
{
        gfn_t gfn = base_gfn;
        pfn_t pfn;
        int i, r = 0;
        struct iommu_domain *domain = kvm->arch.iommu_domain;
        int flags;

        /* check if iommu exists and in use */
        if (!domain)
                return 0;

        flags = IOMMU_READ | IOMMU_WRITE;
        if (kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY)
                flags |= IOMMU_CACHE;

        for (i = 0; i < npages; i++) {
                /* check if already mapped */
                if (iommu_iova_to_phys(domain, gfn_to_gpa(gfn)))
                        continue;

                pfn = gfn_to_pfn(kvm, gfn);
                r = iommu_map_range(domain,
                                    gfn_to_gpa(gfn),
                                    pfn_to_hpa(pfn),
                                    PAGE_SIZE, flags);
                if (r) {
                        printk(KERN_ERR "kvm_iommu_map_address:"
                               "iommu failed to map pfn=%lx\n", pfn);
                        goto unmap_pages;
                }
                gfn++;
        }
        return 0;

unmap_pages:
        kvm_iommu_put_pages(kvm, base_gfn, i);
        return r;
}

static int kvm_iommu_map_memslots(struct kvm *kvm)
{
        int i, r = 0;

        for (i = 0; i < kvm->nmemslots; i++) {
                r = kvm_iommu_map_pages(kvm, kvm->memslots[i].base_gfn,
                                        kvm->memslots[i].npages);
                if (r)
                        break;
        }

        return r;
}

int kvm_assign_device(struct kvm *kvm,
                      struct kvm_assigned_dev_kernel *assigned_dev)
{
        struct pci_dev *pdev = NULL;
        struct iommu_domain *domain = kvm->arch.iommu_domain;
        int r, last_flags;

        /* check if iommu exists and in use */
        if (!domain)
                return 0;

        pdev = assigned_dev->dev;
        if (pdev == NULL)
                return -ENODEV;

        r = iommu_attach_device(domain, &pdev->dev);
        if (r) {
                printk(KERN_ERR "assign device %x:%x.%x failed",
                        pdev->bus->number,
                        PCI_SLOT(pdev->devfn),
                        PCI_FUNC(pdev->devfn));
                return r;
        }

        last_flags = kvm->arch.iommu_flags;
        if (iommu_domain_has_cap(kvm->arch.iommu_domain,
                                 IOMMU_CAP_CACHE_COHERENCY))
                kvm->arch.iommu_flags |= KVM_IOMMU_CACHE_COHERENCY;

        /* Check if need to update IOMMU page table for guest memory */
        if ((last_flags ^ kvm->arch.iommu_flags) ==
                        KVM_IOMMU_CACHE_COHERENCY) {
                kvm_iommu_unmap_memslots(kvm);
                r = kvm_iommu_map_memslots(kvm);
                if (r)
                        goto out_unmap;
        }

        printk(KERN_DEBUG "assign device: host bdf = %x:%x:%x\n",
                assigned_dev->host_busnr,
                PCI_SLOT(assigned_dev->host_devfn),
                PCI_FUNC(assigned_dev->host_devfn));

        return 0;
out_unmap:
        kvm_iommu_unmap_memslots(kvm);
        return r;
}

int kvm_deassign_device(struct kvm *kvm,
                        struct kvm_assigned_dev_kernel *assigned_dev)
{
        struct iommu_domain *domain = kvm->arch.iommu_domain;
        struct pci_dev *pdev = NULL;

        /* check if iommu exists and in use */
        if (!domain)
                return 0;

        pdev = assigned_dev->dev;
        if (pdev == NULL)
                return -ENODEV;

        iommu_detach_device(domain, &pdev->dev);

        printk(KERN_DEBUG "deassign device: host bdf = %x:%x:%x\n",
                assigned_dev->host_busnr,
                PCI_SLOT(assigned_dev->host_devfn),
                PCI_FUNC(assigned_dev->host_devfn));

        return 0;
}

int kvm_iommu_map_guest(struct kvm *kvm)
{
        int r;

        if (!iommu_found()) {
                printk(KERN_ERR "%s: iommu not found\n", __func__);
                return -ENODEV;
        }

        kvm->arch.iommu_domain = iommu_domain_alloc();
        if (!kvm->arch.iommu_domain)
                return -ENOMEM;

        r = kvm_iommu_map_memslots(kvm);
        if (r)
                goto out_unmap;

        return 0;

out_unmap:
        kvm_iommu_unmap_memslots(kvm);
        return r;
}

static void kvm_iommu_put_pages(struct kvm *kvm,
                                gfn_t base_gfn, unsigned long npages)
{
        gfn_t gfn = base_gfn;
        pfn_t pfn;
        struct iommu_domain *domain = kvm->arch.iommu_domain;
        unsigned long i;
        u64 phys;

        /* check if iommu exists and in use */
        if (!domain)
                return;

        for (i = 0; i < npages; i++) {
                phys = iommu_iova_to_phys(domain, gfn_to_gpa(gfn));
                pfn = phys >> PAGE_SHIFT;
                kvm_release_pfn_clean(pfn);
                gfn++;
        }

        iommu_unmap_range(domain, gfn_to_gpa(base_gfn), PAGE_SIZE * npages);
}

static int kvm_iommu_unmap_memslots(struct kvm *kvm)
{
        int i;

        for (i = 0; i < kvm->nmemslots; i++) {
                kvm_iommu_put_pages(kvm, kvm->memslots[i].base_gfn,
                                    kvm->memslots[i].npages);
        }

        return 0;
}

int kvm_iommu_unmap_guest(struct kvm *kvm)
{
        struct iommu_domain *domain = kvm->arch.iommu_domain;

        /* check if iommu exists and in use */
        if (!domain)
                return 0;

        kvm_iommu_unmap_memslots(kvm);
        iommu_domain_free(domain);
        return 0;
}