book3s_64_vio.c

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/*
 * 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, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Copyright 2010 Paul Mackerras, IBM Corp. <[email protected]>
 * Copyright 2011 David Gibson, IBM Corporation <[email protected]>
 */

#include <linux/types.h>
#include <linux/string.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/highmem.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/hugetlb.h>
#include <linux/list.h>
#include <linux/anon_inodes.h>

#include <asm/tlbflush.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include <asm/mmu-hash64.h>
#include <asm/hvcall.h>
#include <asm/synch.h>
#include <asm/ppc-opcode.h>
#include <asm/kvm_host.h>
#include <asm/udbg.h>

#define TCES_PER_PAGE   (PAGE_SIZE / sizeof(u64))

static long kvmppc_stt_npages(unsigned long window_size)
{
    return ALIGN((window_size >> SPAPR_TCE_SHIFT)
             * sizeof(u64), PAGE_SIZE) / PAGE_SIZE;
}

static void release_spapr_tce_table(struct kvmppc_spapr_tce_table *stt)
{
    struct kvm *kvm = stt->kvm;
    int i;

    mutex_lock(&kvm->lock);
    list_del(&stt->list);
    for (i = 0; i < kvmppc_stt_npages(stt->window_size); i++)
        __free_page(stt->pages[i]);
    kfree(stt);
    mutex_unlock(&kvm->lock);

    kvm_put_kvm(kvm);
}

static int kvm_spapr_tce_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
    struct kvmppc_spapr_tce_table *stt = vma->vm_file->private_data;
    struct page *page;

    if (vmf->pgoff >= kvmppc_stt_npages(stt->window_size))
        return VM_FAULT_SIGBUS;

    page = stt->pages[vmf->pgoff];
    get_page(page);
    vmf->page = page;
    return 0;
}

static const struct vm_operations_struct kvm_spapr_tce_vm_ops = {
    .fault = kvm_spapr_tce_fault,
};

static int kvm_spapr_tce_mmap(struct file *file, struct vm_area_struct *vma)
{
    vma->vm_ops = &kvm_spapr_tce_vm_ops;
    return 0;
}

static int kvm_spapr_tce_release(struct inode *inode, struct file *filp)
{
    struct kvmppc_spapr_tce_table *stt = filp->private_data;

    release_spapr_tce_table(stt);
    return 0;
}

static struct file_operations kvm_spapr_tce_fops = {
    .mmap           = kvm_spapr_tce_mmap,
    .release    = kvm_spapr_tce_release,
};

long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
                   struct kvm_create_spapr_tce *args)
{
    struct kvmppc_spapr_tce_table *stt = NULL;
    long npages;
    int ret = -ENOMEM;
    int i;

    /* Check this LIOBN hasn't been previously allocated */
    list_for_each_entry(stt, &kvm->arch.spapr_tce_tables, list) {
        if (stt->liobn == args->liobn)
            return -EBUSY;
    }

    npages = kvmppc_stt_npages(args->window_size);

    stt = kzalloc(sizeof(*stt) + npages * sizeof(struct page *),
              GFP_KERNEL);
    if (!stt)
        goto fail;

    stt->liobn = args->liobn;
    stt->window_size = args->window_size;
    stt->kvm = kvm;

    for (i = 0; i < npages; i++) {
        stt->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO);
        if (!stt->pages[i])
            goto fail;
    }

    kvm_get_kvm(kvm);

    mutex_lock(&kvm->lock);
    list_add(&stt->list, &kvm->arch.spapr_tce_tables);

    mutex_unlock(&kvm->lock);

    return anon_inode_getfd("kvm-spapr-tce", &kvm_spapr_tce_fops,
                stt, O_RDWR);

fail:
    if (stt) {
        for (i = 0; i < npages; i++)
            if (stt->pages[i])
                __free_page(stt->pages[i]);

        kfree(stt);
    }
    return ret;
}