book3s_hv_builtin.c

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/*
 * Copyright 2011 Paul Mackerras, IBM Corp. <[email protected]>
 *
 * 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.
 */

#include <linux/kvm_host.h>
#include <linux/preempt.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/bootmem.h>
#include <linux/init.h>

#include <asm/cputable.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>

#define KVM_LINEAR_RMA      0
#define KVM_LINEAR_HPT      1

static void __init kvm_linear_init_one(ulong size, int count, int type);
static struct kvmppc_linear_info *kvm_alloc_linear(int type);
static void kvm_release_linear(struct kvmppc_linear_info *ri);

int kvm_hpt_order = KVM_DEFAULT_HPT_ORDER;
EXPORT_SYMBOL_GPL(kvm_hpt_order);

/*************** RMA *************/

/*
 * This maintains a list of RMAs (real mode areas) for KVM guests to use.
 * Each RMA has to be physically contiguous and of a size that the
 * hardware supports.  PPC970 and POWER7 support 64MB, 128MB and 256MB,
 * and other larger sizes.  Since we are unlikely to be allocate that
 * much physically contiguous memory after the system is up and running,
 * we preallocate a set of RMAs in early boot for KVM to use.
 */
static unsigned long kvm_rma_size = 64 << 20;   /* 64MB */
static unsigned long kvm_rma_count;

/* Work out RMLS (real mode limit selector) field value for a given RMA size.
   Assumes POWER7 or PPC970. */
static inline int lpcr_rmls(unsigned long rma_size)
{
    switch (rma_size) {
    case 32ul << 20:    /* 32 MB */
        if (cpu_has_feature(CPU_FTR_ARCH_206))
            return 8;   /* only supported on POWER7 */
        return -1;
    case 64ul << 20:    /* 64 MB */
        return 3;
    case 128ul << 20:   /* 128 MB */
        return 7;
    case 256ul << 20:   /* 256 MB */
        return 4;
    case 1ul << 30:     /* 1 GB */
        return 2;
    case 16ul << 30:    /* 16 GB */
        return 1;
    case 256ul << 30:   /* 256 GB */
        return 0;
    default:
        return -1;
    }
}

static int __init early_parse_rma_size(char *p)
{
    if (!p)
        return 1;

    kvm_rma_size = memparse(p, &p);

    return 0;
}
early_param("kvm_rma_size", early_parse_rma_size);

static int __init early_parse_rma_count(char *p)
{
    if (!p)
        return 1;

    kvm_rma_count = simple_strtoul(p, NULL, 0);

    return 0;
}
early_param("kvm_rma_count", early_parse_rma_count);

struct kvmppc_linear_info *kvm_alloc_rma(void)
{
    return kvm_alloc_linear(KVM_LINEAR_RMA);
}
EXPORT_SYMBOL_GPL(kvm_alloc_rma);

void kvm_release_rma(struct kvmppc_linear_info *ri)
{
    kvm_release_linear(ri);
}
EXPORT_SYMBOL_GPL(kvm_release_rma);

/*************** HPT *************/

/*
 * This maintains a list of big linear HPT tables that contain the GVA->HPA
 * memory mappings. If we don't reserve those early on, we might not be able
 * to get a big (usually 16MB) linear memory region from the kernel anymore.
 */

static unsigned long kvm_hpt_count;

static int __init early_parse_hpt_count(char *p)
{
    if (!p)
        return 1;

    kvm_hpt_count = simple_strtoul(p, NULL, 0);

    return 0;
}
early_param("kvm_hpt_count", early_parse_hpt_count);

struct kvmppc_linear_info *kvm_alloc_hpt(void)
{
    return kvm_alloc_linear(KVM_LINEAR_HPT);
}
EXPORT_SYMBOL_GPL(kvm_alloc_hpt);

void kvm_release_hpt(struct kvmppc_linear_info *li)
{
    kvm_release_linear(li);
}
EXPORT_SYMBOL_GPL(kvm_release_hpt);

/*************** generic *************/

static LIST_HEAD(free_linears);
static DEFINE_SPINLOCK(linear_lock);

static void __init kvm_linear_init_one(ulong size, int count, int type)
{
    unsigned long i;
    unsigned long j, npages;
    void *linear;
    struct page *pg;
    const char *typestr;
    struct kvmppc_linear_info *linear_info;

    if (!count)
        return;

    typestr = (type == KVM_LINEAR_RMA) ? "RMA" : "HPT";

    npages = size >> PAGE_SHIFT;
    linear_info = alloc_bootmem(count * sizeof(struct kvmppc_linear_info));
    for (i = 0; i < count; ++i) {
        linear = alloc_bootmem_align(size, size);
        pr_info("Allocated KVM %s at %p (%ld MB)\n", typestr, linear,
            size >> 20);
        linear_info[i].base_virt = linear;
        linear_info[i].base_pfn = __pa(linear) >> PAGE_SHIFT;
        linear_info[i].npages = npages;
        linear_info[i].type = type;
        list_add_tail(&linear_info[i].list, &free_linears);
        atomic_set(&linear_info[i].use_count, 0);

        pg = pfn_to_page(linear_info[i].base_pfn);
        for (j = 0; j < npages; ++j) {
            atomic_inc(&pg->_count);
            ++pg;
        }
    }
}

static struct kvmppc_linear_info *kvm_alloc_linear(int type)
{
    struct kvmppc_linear_info *ri, *ret;

    ret = NULL;
    spin_lock(&linear_lock);
    list_for_each_entry(ri, &free_linears, list) {
        if (ri->type != type)
            continue;

        list_del(&ri->list);
        atomic_inc(&ri->use_count);
        memset(ri->base_virt, 0, ri->npages << PAGE_SHIFT);
        ret = ri;
        break;
    }
    spin_unlock(&linear_lock);
    return ret;
}

static void kvm_release_linear(struct kvmppc_linear_info *ri)
{
    if (atomic_dec_and_test(&ri->use_count)) {
        spin_lock(&linear_lock);
        list_add_tail(&ri->list, &free_linears);
        spin_unlock(&linear_lock);

    }
}

/*
 * Called at boot time while the bootmem allocator is active,
 * to allocate contiguous physical memory for the hash page
 * tables for guests.
 */
void __init kvm_linear_init(void)
{
    /* HPT */
    kvm_linear_init_one(1 << kvm_hpt_order, kvm_hpt_count, KVM_LINEAR_HPT);

    /* RMA */
    /* Only do this on PPC970 in HV mode */
    if (!cpu_has_feature(CPU_FTR_HVMODE) ||
        !cpu_has_feature(CPU_FTR_ARCH_201))
        return;

    if (!kvm_rma_size || !kvm_rma_count)
        return;

    /* Check that the requested size is one supported in hardware */
    if (lpcr_rmls(kvm_rma_size) < 0) {
        pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
        return;
    }

    kvm_linear_init_one(kvm_rma_size, kvm_rma_count, KVM_LINEAR_RMA);
}