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/*
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 * PowerPC KVM support
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 *
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 * Copyright IBM Corp. 2008
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 *
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 * Authors:
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 *  Hollis Blanchard <hollisb@us.ibm.com>
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 *
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 * This work is licensed under the terms of the GNU GPL, version 2 or later.
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 * See the COPYING file in the top-level directory.
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 *
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 */
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#include "qemu-common.h"
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#include "qemu-timer.h"
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#include "kvm_ppc.h"
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#include "device_tree.h"
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#define PROC_DEVTREE_PATH "/proc/device-tree"
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static QEMUTimer *kvmppc_timer;
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static unsigned int kvmppc_timer_rate;
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#ifdef CONFIG_FDT
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int kvmppc_read_host_property(const char *node_path, const char *prop,
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                                     void *val, size_t len)
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{
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    char *path;
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    FILE *f;
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    int ret = 0;
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    int pathlen;
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    pathlen = snprintf(NULL, 0, "%s/%s/%s", PROC_DEVTREE_PATH, node_path, prop)
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              + 1;
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    path = qemu_malloc(pathlen);
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    snprintf(path, pathlen, "%s/%s/%s", PROC_DEVTREE_PATH, node_path, prop);
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    f = fopen(path, "rb");
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    if (f == NULL) {
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        ret = errno;
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        goto free;
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    }
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    len = fread(val, len, 1, f);
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    if (len != 1) {
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        ret = ferror(f);
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        goto close;
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    }
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close:
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    fclose(f);
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free:
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    free(path);
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    return ret;
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}
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static int kvmppc_copy_host_cell(void *fdt, const char *node, const char *prop)
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{
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    uint32_t cell;
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    int ret;
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    ret = kvmppc_read_host_property(node, prop, &cell, sizeof(cell));
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    if (ret < 0) {
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        fprintf(stderr, "couldn't read host %s/%s\n", node, prop);
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        goto out;
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    }
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    ret = qemu_devtree_setprop_cell(fdt, node, prop, cell);
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    if (ret < 0) {
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        fprintf(stderr, "couldn't set guest %s/%s\n", node, prop);
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        goto out;
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    }
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out:
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    return ret;
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}
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void kvmppc_fdt_update(void *fdt)
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{
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    /* Copy data from the host device tree into the guest. Since the guest can
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     * directly access the timebase without host involvement, we must expose
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     * the correct frequencies. */
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    kvmppc_copy_host_cell(fdt, "/cpus/cpu@0", "clock-frequency");
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    kvmppc_copy_host_cell(fdt, "/cpus/cpu@0", "timebase-frequency");
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}
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#endif
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static void kvmppc_timer_hack(void *opaque)
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{
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    qemu_service_io();
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    qemu_mod_timer(kvmppc_timer, qemu_get_clock(vm_clock) + kvmppc_timer_rate);
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}
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void kvmppc_init(void)
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{
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    /* XXX The only reason KVM yields control back to qemu is device IO. Since
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     * an idle guest does no IO, qemu's device model will never get a chance to
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     * run. So, until Qemu gains IO threads, we create this timer to ensure
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     * that the device model gets a chance to run. */
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    kvmppc_timer_rate = get_ticks_per_sec() / 10;
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    kvmppc_timer = qemu_new_timer(vm_clock, &kvmppc_timer_hack, NULL);
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    qemu_mod_timer(kvmppc_timer, qemu_get_clock(vm_clock) + kvmppc_timer_rate);
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}