xen: pv domain builder. (Gerd Hoffmann)

This adds domain building support for paravirtual domains to qemu.
This allows booting xen guests directly with qemu, without Xend
and the management stack.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7226 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 294 insertions, 0 deletions

diff --git a/hw/xen_domainbuild.c b/hw/xen_domainbuild.c
new file mode 100644
index 0000000000..21710ebf17
--- /dev/null
+++ b/hw/xen_domainbuild.c
@@ -0,0 +1,294 @@
+#include <signal.h>
+#include "xen_backend.h"
+#include "xen_domainbuild.h"
+#include "sysemu.h"
+#include "qemu-timer.h"
+
+#include <xenguest.h>
+
+static int xenstore_domain_mkdir(char *path)
+{
+    struct xs_permissions perms_ro[] = {{
+            .id    = 0, /* set owner: dom0 */
+        },{
+            .id    = xen_domid,
+            .perms = XS_PERM_READ,
+        }};
+    struct xs_permissions perms_rw[] = {{
+            .id    = 0, /* set owner: dom0 */
+        },{
+            .id    = xen_domid,
+            .perms = XS_PERM_READ | XS_PERM_WRITE,
+        }};
+    const char *writable[] = { "device", "control", "error", NULL };
+    char subpath[256];
+    int i;
+
+    if (!xs_mkdir(xenstore, 0, path)) {
+        fprintf(stderr, "%s: xs_mkdir %s: failed\n", __FUNCTION__, path);
+	return -1;
+    }
+    if (!xs_set_permissions(xenstore, 0, path, perms_ro, 2)) {
+        fprintf(stderr, "%s: xs_set_permissions failed\n", __FUNCTION__);
+	return -1;
+    }
+
+    for (i = 0; writable[i]; i++) {
+        snprintf(subpath, sizeof(subpath), "%s/%s", path, writable[i]);
+        if (!xs_mkdir(xenstore, 0, subpath)) {
+            fprintf(stderr, "%s: xs_mkdir %s: failed\n", __FUNCTION__, subpath);
+            return -1;
+        }
+        if (!xs_set_permissions(xenstore, 0, subpath, perms_rw, 2)) {
+            fprintf(stderr, "%s: xs_set_permissions failed\n", __FUNCTION__);
+            return -1;
+        }
+    }
+    return 0;
+}
+
+int xenstore_domain_init1(const char *kernel, const char *ramdisk,
+                          const char *cmdline)
+{
+    char *dom, uuid_string[42], vm[256], path[256];
+    int i;
+
+    snprintf(uuid_string, sizeof(uuid_string), UUID_FMT,
+             qemu_uuid[0], qemu_uuid[1], qemu_uuid[2], qemu_uuid[3],
+             qemu_uuid[4], qemu_uuid[5], qemu_uuid[6], qemu_uuid[7],
+             qemu_uuid[8], qemu_uuid[9], qemu_uuid[10], qemu_uuid[11],
+             qemu_uuid[12], qemu_uuid[13], qemu_uuid[14], qemu_uuid[15]);
+    dom = xs_get_domain_path(xenstore, xen_domid);
+    snprintf(vm,  sizeof(vm),  "/vm/%s", uuid_string);
+
+    xenstore_domain_mkdir(dom);
+
+    xenstore_write_str(vm, "image/ostype",  "linux");
+    if (kernel)
+        xenstore_write_str(vm, "image/kernel",  kernel);
+    if (ramdisk)
+        xenstore_write_str(vm, "image/ramdisk", ramdisk);
+    if (cmdline)
+        xenstore_write_str(vm, "image/cmdline", cmdline);
+
+    /* name + id */
+    xenstore_write_str(vm,  "name",   qemu_name ? qemu_name : "no-name");
+    xenstore_write_str(vm,  "uuid",   uuid_string);
+    xenstore_write_str(dom, "name",   qemu_name ? qemu_name : "no-name");
+    xenstore_write_int(dom, "domid",  xen_domid);
+    xenstore_write_str(dom, "vm",     vm);
+
+    /* memory */
+    xenstore_write_int(dom, "memory/target", ram_size >> 10);  // kB
+    xenstore_write_int(vm, "memory",         ram_size >> 20);  // MB
+    xenstore_write_int(vm, "maxmem",         ram_size >> 20);  // MB
+
+    /* cpus */
+    for (i = 0; i < smp_cpus; i++) {
+	snprintf(path, sizeof(path), "cpu/%d/availability",i);
+	xenstore_write_str(dom, path, "online");
+    }
+    xenstore_write_int(vm, "vcpu_avail",  smp_cpus);
+    xenstore_write_int(vm, "vcpus",       smp_cpus);
+
+    /* vnc password */
+    xenstore_write_str(vm, "vncpassword", "" /* FIXME */);
+
+    free(dom);
+    return 0;
+}
+
+int xenstore_domain_init2(int xenstore_port, int xenstore_mfn,
+                          int console_port, int console_mfn)
+{
+    char *dom;
+
+    dom = xs_get_domain_path(xenstore, xen_domid);
+
+    /* signal new domain */
+    xs_introduce_domain(xenstore,
+                        xen_domid,
+                        xenstore_mfn,
+                        xenstore_port);
+
+    /* xenstore */
+    xenstore_write_int(dom, "store/ring-ref",   xenstore_mfn);
+    xenstore_write_int(dom, "store/port",       xenstore_port);
+
+    /* console */
+    xenstore_write_str(dom, "console/type",     "ioemu");
+    xenstore_write_int(dom, "console/limit",    128 * 1024);
+    xenstore_write_int(dom, "console/ring-ref", console_mfn);
+    xenstore_write_int(dom, "console/port",     console_port);
+    xen_config_dev_console(0);
+
+    free(dom);
+    return 0;
+}
+
+/* ------------------------------------------------------------- */
+
+static QEMUTimer *xen_poll;
+
+/* check domain state once per second */
+static void xen_domain_poll(void *opaque)
+{
+    struct xc_dominfo info;
+    int rc;
+
+    rc = xc_domain_getinfo(xen_xc, xen_domid, 1, &info);
+    if ((1 != rc) || (info.domid != xen_domid)) {
+        qemu_log("xen: domain %d is gone\n", xen_domid);
+        goto quit;
+    }
+    if (info.dying) {
+        qemu_log("xen: domain %d is dying (%s%s)\n", xen_domid,
+                 info.crashed  ? "crashed"  : "",
+                 info.shutdown ? "shutdown" : "");
+        goto quit;
+    }
+
+    qemu_mod_timer(xen_poll, qemu_get_clock(rt_clock) + 1000);
+    return;
+
+quit:
+    qemu_system_shutdown_request();
+    return;
+}
+
+static void xen_domain_watcher(void)
+{
+    int qemu_running = 1;
+    int fd[2], i, n, rc;
+    char byte;
+
+    pipe(fd);
+    if (fork() != 0)
+        return; /* not child */
+
+    /* close all file handles, except stdio/out/err,
+     * our watch pipe and the xen interface handle */
+    n = getdtablesize();
+    for (i = 3; i < n; i++) {
+        if (i == fd[0])
+            continue;
+        if (i == xen_xc)
+            continue;
+        close(i);
+    }
+
+    /* ignore term signals */
+    signal(SIGINT,  SIG_IGN);
+    signal(SIGTERM, SIG_IGN);
+
+    /* wait for qemu exiting */
+    while (qemu_running) {
+        rc = read(fd[0], &byte, 1);
+        switch (rc) {
+        case -1:
+            if (EINTR == errno)
+                continue;
+            qemu_log("%s: Huh? read error: %s\n", __FUNCTION__, strerror(errno));
+            qemu_running = 0;
+            break;
+        case 0:
+            /* EOF -> qemu exited */
+            qemu_running = 0;
+            break;
+        default:
+            qemu_log("%s: Huh? data on the watch pipe?\n", __FUNCTION__);
+            break;
+        }
+    }
+
+    /* cleanup */
+    qemu_log("%s: destroy domain %d\n", __FUNCTION__, xen_domid);
+    xc_domain_destroy(xen_xc, xen_domid);
+    _exit(0);
+}
+
+/* normal cleanup */
+static void xen_domain_cleanup(void)
+{
+    char *dom;
+
+    dom = xs_get_domain_path(xenstore, xen_domid);
+    if (dom) {
+        xs_rm(xenstore, 0, dom);
+        free(dom);
+    }
+    xs_release_domain(xenstore, xen_domid);
+}
+
+int xen_domain_build_pv(const char *kernel, const char *ramdisk,
+                        const char *cmdline)
+{
+    uint32_t ssidref = 0;
+    uint32_t flags = 0;
+    xen_domain_handle_t uuid;
+    unsigned int xenstore_port = 0, console_port = 0;
+    unsigned long xenstore_mfn = 0, console_mfn = 0;
+    int rc;
+
+    memcpy(uuid, qemu_uuid, sizeof(uuid));
+    rc = xc_domain_create(xen_xc, ssidref, uuid, flags, &xen_domid);
+    if (rc < 0) {
+        fprintf(stderr, "xen: xc_domain_create() failed\n");
+        goto err;
+    }
+    qemu_log("xen: created domain %d\n", xen_domid);
+    atexit(xen_domain_cleanup);
+    xen_domain_watcher();
+
+    xenstore_domain_init1(kernel, ramdisk, cmdline);
+
+    rc = xc_domain_max_vcpus(xen_xc, xen_domid, smp_cpus);
+    if (rc < 0) {
+        fprintf(stderr, "xen: xc_domain_max_vcpus() failed\n");
+        goto err;
+    }
+
+#if 0
+    rc = xc_domain_setcpuweight(xen_xc, xen_domid, 256);
+    if (rc < 0) {
+        fprintf(stderr, "xen: xc_domain_setcpuweight() failed\n");
+        goto err;
+    }
+#endif
+
+    rc = xc_domain_setmaxmem(xen_xc, xen_domid, ram_size >> 10);
+    if (rc < 0) {
+        fprintf(stderr, "xen: xc_domain_setmaxmem() failed\n");
+        goto err;
+    }
+
+    xenstore_port = xc_evtchn_alloc_unbound(xen_xc, xen_domid, 0);
+    console_port = xc_evtchn_alloc_unbound(xen_xc, xen_domid, 0);
+
+    rc = xc_linux_build(xen_xc, xen_domid, ram_size >> 20,
+                        kernel, ramdisk, cmdline,
+                        0, flags,
+                        xenstore_port, &xenstore_mfn,
+                        console_port, &console_mfn);
+    if (rc < 0) {
+        fprintf(stderr, "xen: xc_linux_build() failed\n");
+        goto err;
+    }
+
+    xenstore_domain_init2(xenstore_port, xenstore_mfn,
+                          console_port, console_mfn);
+
+    qemu_log("xen: unpausing domain %d\n", xen_domid);
+    rc = xc_domain_unpause(xen_xc, xen_domid);
+    if (rc < 0) {
+        fprintf(stderr, "xen: xc_domain_unpause() failed\n");
+        goto err;
+    }
+
+    xen_poll = qemu_new_timer(rt_clock, xen_domain_poll, NULL);
+    qemu_mod_timer(xen_poll, qemu_get_clock(rt_clock) + 1000);
+    return 0;
+
+err:
+    return -1;
+}