Archipelago » qemu

/*

 * PowerPC KVM support

 *

 * Copyright IBM Corp. 2008

 *

 * Authors:

 *  Hollis Blanchard <hollisb@us.ibm.com>

 *

 * This work is licensed under the terms of the GNU GPL, version 2 or later.

 * See the COPYING file in the top-level directory.

 *

 */

#include "qemu-common.h"

#include "qemu-timer.h"

#include "kvm_ppc.h"

#include "device_tree.h"

#define PROC_DEVTREE_PATH "/proc/device-tree"

static QEMUTimer *kvmppc_timer;

static unsigned int kvmppc_timer_rate;

#ifdef CONFIG_FDT

int kvmppc_read_host_property(const char *node_path, const char *prop,

                                     void *val, size_t len)

{

    char *path;

    FILE *f;

    int ret = 0;

    int pathlen;

    pathlen = snprintf(NULL, 0, "%s/%s/%s", PROC_DEVTREE_PATH, node_path, prop)

              + 1;

    path = qemu_malloc(pathlen);

    snprintf(path, pathlen, "%s/%s/%s", PROC_DEVTREE_PATH, node_path, prop);

    f = fopen(path, "rb");

    if (f == NULL) {

        ret = errno;

        goto free;

    }

    len = fread(val, len, 1, f);

    if (len != 1) {

        ret = ferror(f);

        goto close;

    }

close:

    fclose(f);

free:

    free(path);

    return ret;

}

static int kvmppc_copy_host_cell(void *fdt, const char *node, const char *prop)

{

    uint32_t cell;

    int ret;

    ret = kvmppc_read_host_property(node, prop, &cell, sizeof(cell));

    if (ret < 0) {

        fprintf(stderr, "couldn't read host %s/%s\n", node, prop);

        goto out;

    }

    ret = qemu_devtree_setprop_cell(fdt, node, prop, cell);

    if (ret < 0) {

        fprintf(stderr, "couldn't set guest %s/%s\n", node, prop);

        goto out;

    }

out:

    return ret;

}

void kvmppc_fdt_update(void *fdt)

{

    /* Copy data from the host device tree into the guest. Since the guest can

     * directly access the timebase without host involvement, we must expose

     * the correct frequencies. */

    kvmppc_copy_host_cell(fdt, "/cpus/cpu@0", "clock-frequency");

    kvmppc_copy_host_cell(fdt, "/cpus/cpu@0", "timebase-frequency");

}

#endif

static void kvmppc_timer_hack(void *opaque)

{

    qemu_service_io();

    qemu_mod_timer(kvmppc_timer, qemu_get_clock_ns(vm_clock) + kvmppc_timer_rate);

}

void kvmppc_init(void)

{

    /* XXX The only reason KVM yields control back to qemu is device IO. Since

     * an idle guest does no IO, qemu's device model will never get a chance to

     * run. So, until Qemu gains IO threads, we create this timer to ensure

     * that the device model gets a chance to run. */

    kvmppc_timer_rate = get_ticks_per_sec() / 10;

    kvmppc_timer = qemu_new_timer_ns(vm_clock, &kvmppc_timer_hack, NULL);

    qemu_mod_timer(kvmppc_timer, qemu_get_clock_ns(vm_clock) + kvmppc_timer_rate);

}