libxl: Add support for virtio-disk configuration

This patch adds basic support for configuring and assisting virtio-disk
backend (emualator) which is intended to run out of Qemu and could be run
in any domain.

Xenstore was chosen as a communication interface for the emulator running
in non-toolstack domain to be able to get configuration either by reading
Xenstore directly or by receiving command line parameters (an updated 'xl devd'
running in the same domain would read Xenstore beforehand and call backend
executable with the required arguments).

An example of domain configuration (two disks are assigned to the guest,
the latter is in readonly mode):

vdisk = [ 'backend=DomD, disks=rw:/dev/mmcblk0p3;ro:/dev/mmcblk1p3' ]

Where per-disk Xenstore entries are:
- filename and readonly flag (configured via "vdisk" property)
- base and irq (allocated dynamically)

Besides handling 'visible' params described in configuration file,
patch also allocates virtio-mmio specific ones for each device and
writes them into Xenstore. virtio-mmio params (irq and base) are
unique per guest domain, they allocated at the domain creation time
and passed through to the emulator. Each VirtIO device has at least
one pair of these params.

TODO:
1. An extra "virtio" property could be removed.
2. Update documentation.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

Message-Id: <1602780274-29141-24-git-send-email-olekstysh@gmail.com>

12 files changed, 354 insertions, 11 deletions

diff --git a/tools/libs/light/Makefile b/tools/libs/light/Makefile
index f58a3214e5..2ee388a759 100644
--- a/tools/libs/light/Makefile
+++ b/tools/libs/light/Makefile
@@ -115,6 +115,7 @@ SRCS-y += libxl_genid.c
 SRCS-y += _libxl_types.c
 SRCS-y += libxl_flask.c
 SRCS-y += _libxl_types_internal.c
+SRCS-y += libxl_virtio_disk.c
 
 ifeq ($(CONFIG_LIBNL),y)
 CFLAGS_LIBXL += $(LIBNL3_CFLAGS)
diff --git a/tools/libs/light/libxl_arm.c b/tools/libs/light/libxl_arm.c
index 588ee5a6ec..9eb3022889 100644
--- a/tools/libs/light/libxl_arm.c
+++ b/tools/libs/light/libxl_arm.c
@@ -8,6 +8,12 @@
 #include <assert.h>
 #include <xen/device_tree_defs.h>
 
+#ifndef container_of
+#define container_of(ptr, type, member) ({			\
+        typeof( ((type *)0)->member ) *__mptr = (ptr);	\
+        (type *)( (char *)__mptr - offsetof(type,member) );})
+#endif
+
 static const char *gicv_to_string(libxl_gic_version gic_version)
 {
     switch (gic_version) {
@@ -39,14 +45,32 @@ int libxl__arch_domain_prepare_config(libxl__gc *gc,
         vuart_enabled = true;
     }
 
-    /*
-     * XXX: Handle properly virtio
-     * A proper solution would be the toolstack to allocate the interrupts
-     * used by each virtio backend and let the backend now which one is used
-     */
     if (libxl_defbool_val(d_config->b_info.arch_arm.virtio)) {
-        nr_spis += (GUEST_VIRTIO_MMIO_SPI - 32) + 1;
+        uint64_t virtio_base;
+        libxl_device_virtio_disk *virtio_disk;
+
+        virtio_base = GUEST_VIRTIO_MMIO_BASE;
         virtio_irq = GUEST_VIRTIO_MMIO_SPI;
+
+        if (!d_config->num_virtio_disks) {
+            LOG(ERROR, "Virtio is enabled, but no Virtio devices present\n");
+            return ERROR_FAIL;
+        }
+        virtio_disk = &d_config->virtio_disks[0];
+
+        for (i = 0; i < virtio_disk->num_disks; i++) {
+            virtio_disk->disks[i].base = virtio_base;
+            virtio_disk->disks[i].irq = virtio_irq;
+
+            LOG(DEBUG, "Allocate Virtio MMIO params: IRQ %u BASE 0x%"PRIx64,
+                virtio_irq, virtio_base);
+
+            virtio_irq ++;
+            virtio_base += GUEST_VIRTIO_MMIO_SIZE;
+        }
+        virtio_irq --;
+
+        nr_spis += (virtio_irq - 32) + 1;
         virtio_enabled = true;
     }
 
@@ -70,8 +94,9 @@ int libxl__arch_domain_prepare_config(libxl__gc *gc,
         }
 
         /* The same check as for vpl011 */
-        if (virtio_enabled && irq == virtio_irq) {
-            LOG(ERROR, "Physical IRQ %u conflicting with virtio SPI\n", irq);
+        if (virtio_enabled &&
+           (irq >= GUEST_VIRTIO_MMIO_SPI && irq <= virtio_irq)) {
+            LOG(ERROR, "Physical IRQ %u conflicting with Virtio IRQ range\n", irq);
             return ERROR_FAIL;
         }
 
@@ -1011,8 +1036,19 @@ next_resize:
         if (info->tee == LIBXL_TEE_TYPE_OPTEE)
             FDT( make_optee_node(gc, fdt) );
 
-        if (libxl_defbool_val(info->arch_arm.virtio))
-            FDT( make_virtio_mmio_node(gc, fdt, GUEST_VIRTIO_MMIO_BASE, GUEST_VIRTIO_MMIO_SPI) );
+        if (libxl_defbool_val(info->arch_arm.virtio)) {
+            libxl_domain_config *d_config =
+                container_of(info, libxl_domain_config, b_info);
+            libxl_device_virtio_disk *virtio_disk = &d_config->virtio_disks[0];
+            unsigned int i;
+
+            for (i = 0; i < virtio_disk->num_disks; i++) {
+                uint64_t base = virtio_disk->disks[i].base;
+                uint32_t irq = virtio_disk->disks[i].irq;
+
+                FDT( make_virtio_mmio_node(gc, fdt, base, irq) );
+            }
+        }
 
         if (pfdt)
             FDT( copy_partial_fdt(gc, fdt, pfdt) );
diff --git a/tools/libs/light/libxl_create.c b/tools/libs/light/libxl_create.c
index 321a13e519..8da328dca0 100644
--- a/tools/libs/light/libxl_create.c
+++ b/tools/libs/light/libxl_create.c
@@ -1821,6 +1821,7 @@ const libxl__device_type *device_type_tbl[] = {
     &libxl__dtdev_devtype,
     &libxl__vdispl_devtype,
     &libxl__vsnd_devtype,
+    &libxl__virtio_disk_devtype,
     NULL
 };
 
diff --git a/tools/libs/light/libxl_internal.h b/tools/libs/light/libxl_internal.h
index e26cda9b50..ea497bb2eb 100644
--- a/tools/libs/light/libxl_internal.h
+++ b/tools/libs/light/libxl_internal.h
@@ -4000,6 +4000,7 @@ extern const libxl__device_type libxl__vdispl_devtype;
 extern const libxl__device_type libxl__p9_devtype;
 extern const libxl__device_type libxl__pvcallsif_devtype;
 extern const libxl__device_type libxl__vsnd_devtype;
+extern const libxl__device_type libxl__virtio_disk_devtype;
 
 extern const libxl__device_type *device_type_tbl[];
 
diff --git a/tools/libs/light/libxl_types.idl b/tools/libs/light/libxl_types.idl
index b054bf9e5d..5f8a3ff3c4 100644
--- a/tools/libs/light/libxl_types.idl
+++ b/tools/libs/light/libxl_types.idl
@@ -935,6 +935,20 @@ libxl_device_vsnd = Struct("device_vsnd", [
     ("pcms", Array(libxl_vsnd_pcm, "num_vsnd_pcms"))
     ])
 
+libxl_virtio_disk_param = Struct("virtio_disk_param", [
+    ("filename", string),
+    ("readonly", bool),
+    ("irq", uint32),
+    ("base", uint64),
+    ])
+
+libxl_device_virtio_disk = Struct("device_virtio_disk", [
+    ("backend_domid", libxl_domid),
+    ("backend_domname", string),
+    ("devid", libxl_devid),
+    ("disks", Array(libxl_virtio_disk_param, "num_disks")),
+    ])
+
 libxl_domain_config = Struct("domain_config", [
     ("c_info", libxl_domain_create_info),
     ("b_info", libxl_domain_build_info),
@@ -951,6 +965,7 @@ libxl_domain_config = Struct("domain_config", [
     ("pvcallsifs", Array(libxl_device_pvcallsif, "num_pvcallsifs")),
     ("vdispls", Array(libxl_device_vdispl, "num_vdispls")),
     ("vsnds", Array(libxl_device_vsnd, "num_vsnds")),
+    ("virtio_disks", Array(libxl_device_virtio_disk, "num_virtio_disks")),
     # a channel manifests as a console with a name,
     # see docs/misc/channels.txt
     ("channels", Array(libxl_device_channel, "num_channels")),
diff --git a/tools/libs/light/libxl_types_internal.idl b/tools/libs/light/libxl_types_internal.idl
index 3593e21dbb..8f71980aec 100644
--- a/tools/libs/light/libxl_types_internal.idl
+++ b/tools/libs/light/libxl_types_internal.idl
@@ -32,6 +32,7 @@ libxl__device_kind = Enumeration("device_kind", [
     (14, "PVCALLS"),
     (15, "VSND"),
     (16, "VINPUT"),
+    (17, "VIRTIO_DISK"),
     ])
 
 libxl__console_backend = Enumeration("console_backend", [
diff --git a/tools/libs/light/libxl_virtio_disk.c b/tools/libs/light/libxl_virtio_disk.c
new file mode 100644
index 0000000000..25e7f1a37f
--- /dev/null
+++ b/tools/libs/light/libxl_virtio_disk.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2020 EPAM Systems Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; version 2.1 only. with the special
+ * exception on linking described in file LICENSE.
+ *
+ * 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 Lesser General Public License for more details.
+ */
+
+#include "libxl_internal.h"
+
+static int libxl__device_virtio_disk_setdefault(libxl__gc *gc, uint32_t domid,
+                                                libxl_device_virtio_disk *virtio_disk,
+                                                bool hotplug)
+{
+    return libxl__resolve_domid(gc, virtio_disk->backend_domname,
+                                &virtio_disk->backend_domid);
+}
+
+static int libxl__virtio_disk_from_xenstore(libxl__gc *gc, const char *libxl_path,
+                                            libxl_devid devid,
+                                            libxl_device_virtio_disk *virtio_disk)
+{
+    const char *be_path;
+    int rc;
+
+    virtio_disk->devid = devid;
+    rc = libxl__xs_read_mandatory(gc, XBT_NULL,
+                                  GCSPRINTF("%s/backend", libxl_path),
+                                  &be_path);
+    if (rc) return rc;
+
+    rc = libxl__backendpath_parse_domid(gc, be_path, &virtio_disk->backend_domid);
+    if (rc) return rc;
+
+    return 0;
+}
+
+static void libxl__update_config_virtio_disk(libxl__gc *gc,
+                                             libxl_device_virtio_disk *dst,
+                                             libxl_device_virtio_disk *src)
+{
+    dst->devid = src->devid;
+}
+
+static int libxl_device_virtio_disk_compare(libxl_device_virtio_disk *d1,
+                                            libxl_device_virtio_disk *d2)
+{
+    return COMPARE_DEVID(d1, d2);
+}
+
+static void libxl__device_virtio_disk_add(libxl__egc *egc, uint32_t domid,
+                                          libxl_device_virtio_disk *virtio_disk,
+                                          libxl__ao_device *aodev)
+{
+    libxl__device_add_async(egc, domid, &libxl__virtio_disk_devtype, virtio_disk, aodev);
+}
+
+static int libxl__set_xenstore_virtio_disk(libxl__gc *gc, uint32_t domid,
+                                           libxl_device_virtio_disk *virtio_disk,
+                                           flexarray_t *back, flexarray_t *front,
+                                           flexarray_t *ro_front)
+{
+    int rc;
+    unsigned int i;
+
+    for (i = 0; i < virtio_disk->num_disks; i++) {
+        rc = flexarray_append_pair(ro_front, GCSPRINTF("%d/filename", i),
+                                   GCSPRINTF("%s", virtio_disk->disks[i].filename));
+        if (rc) return rc;
+
+        rc = flexarray_append_pair(ro_front, GCSPRINTF("%d/readonly", i),
+                                   GCSPRINTF("%d", virtio_disk->disks[i].readonly));
+        if (rc) return rc;
+
+        rc = flexarray_append_pair(ro_front, GCSPRINTF("%d/base", i),
+                                   GCSPRINTF("%lu", virtio_disk->disks[i].base));
+        if (rc) return rc;
+
+        rc = flexarray_append_pair(ro_front, GCSPRINTF("%d/irq", i),
+                                   GCSPRINTF("%u", virtio_disk->disks[i].irq));
+        if (rc) return rc;
+    }
+
+    return 0;
+}
+
+static LIBXL_DEFINE_UPDATE_DEVID(virtio_disk)
+static LIBXL_DEFINE_DEVICE_FROM_TYPE(virtio_disk)
+static LIBXL_DEFINE_DEVICES_ADD(virtio_disk)
+
+DEFINE_DEVICE_TYPE_STRUCT(virtio_disk, VIRTIO_DISK,
+    .update_config = (device_update_config_fn_t) libxl__update_config_virtio_disk,
+    .from_xenstore = (device_from_xenstore_fn_t) libxl__virtio_disk_from_xenstore,
+    .set_xenstore_config = (device_set_xenstore_config_fn_t) libxl__set_xenstore_virtio_disk
+);
+
+/*
+ * Local variables:
+ * mode: C
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/tools/xl/Makefile b/tools/xl/Makefile
index bdf67c8464..9d8f2aafb2 100644
--- a/tools/xl/Makefile
+++ b/tools/xl/Makefile
@@ -23,7 +23,7 @@ XL_OBJS += xl_vtpm.o xl_block.o xl_nic.o xl_usb.o
 XL_OBJS += xl_sched.o xl_pci.o xl_vcpu.o xl_cdrom.o xl_mem.o
 XL_OBJS += xl_info.o xl_console.o xl_misc.o
 XL_OBJS += xl_vmcontrol.o xl_saverestore.o xl_migrate.o
-XL_OBJS += xl_vdispl.o xl_vsnd.o xl_vkb.o
+XL_OBJS += xl_vdispl.o xl_vsnd.o xl_vkb.o xl_virtio_disk.o
 
 $(XL_OBJS): CFLAGS += $(CFLAGS_libxentoollog)
 $(XL_OBJS): CFLAGS += $(CFLAGS_XL)
diff --git a/tools/xl/xl.h b/tools/xl/xl.h
index 06569c6c4a..3d26f19b59 100644
--- a/tools/xl/xl.h
+++ b/tools/xl/xl.h
@@ -178,6 +178,9 @@ int main_vsnddetach(int argc, char **argv);
 int main_vkbattach(int argc, char **argv);
 int main_vkblist(int argc, char **argv);
 int main_vkbdetach(int argc, char **argv);
+int main_virtio_diskattach(int argc, char **argv);
+int main_virtio_disklist(int argc, char **argv);
+int main_virtio_diskdetach(int argc, char **argv);
 int main_usbctrl_attach(int argc, char **argv);
 int main_usbctrl_detach(int argc, char **argv);
 int main_usbdev_attach(int argc, char **argv);
diff --git a/tools/xl/xl_cmdtable.c b/tools/xl/xl_cmdtable.c
index 7da6c1b927..745afabdeb 100644
--- a/tools/xl/xl_cmdtable.c
+++ b/tools/xl/xl_cmdtable.c
@@ -435,6 +435,21 @@ struct cmd_spec cmd_table[] = {
       "Destroy a domain's virtual sound device",
       "<Domain> <DevId>",
     },
+    { "virtio-disk-attach",
+      &main_virtio_diskattach, 1, 1,
+      "Create a new virtio block device",
+      " TBD\n"
+    },
+    { "virtio-disk-list",
+      &main_virtio_disklist, 0, 0,
+      "List virtio block devices for a domain",
+      "<Domain(s)>",
+    },
+    { "virtio-disk-detach",
+      &main_virtio_diskdetach, 0, 1,
+      "Destroy a domain's virtio block device",
+      "<Domain> <DevId>",
+    },
     { "uptime",
       &main_uptime, 0, 0,
       "Print uptime for all/some domains",
diff --git a/tools/xl/xl_parse.c b/tools/xl/xl_parse.c
index 10acf22c0d..6cf352486e 100644
--- a/tools/xl/xl_parse.c
+++ b/tools/xl/xl_parse.c
@@ -1204,6 +1204,120 @@ out:
     if (rc) exit(EXIT_FAILURE);
 }
 
+#define MAX_VIRTIO_DISKS 4
+
+static int parse_virtio_disk_config(libxl_device_virtio_disk *virtio_disk, char *token)
+{
+    char *oparg;
+    libxl_string_list disks = NULL;
+    int i, rc;
+
+    if (MATCH_OPTION("backend", token, oparg)) {
+        virtio_disk->backend_domname = strdup(oparg);
+    } else if (MATCH_OPTION("disks", token, oparg)) {
+        split_string_into_string_list(oparg, ";", &disks);
+
+        virtio_disk->num_disks = libxl_string_list_length(&disks);
+        if (virtio_disk->num_disks > MAX_VIRTIO_DISKS) {
+            fprintf(stderr, "vdisk: currently only %d disks are supported",
+                    MAX_VIRTIO_DISKS);
+            return 1;
+        }
+        virtio_disk->disks = xcalloc(virtio_disk->num_disks,
+                                     sizeof(*virtio_disk->disks));
+
+        for(i = 0; i < virtio_disk->num_disks; i++) {
+            char *disk_opt;
+
+            rc = split_string_into_pair(disks[i], ":", &disk_opt,
+                                        &virtio_disk->disks[i].filename);
+            if (rc) {
+                fprintf(stderr, "vdisk: failed to split \"%s\" into pair\n",
+                        disks[i]);
+                goto out;
+            }
+
+            if (!strcmp(disk_opt, "ro"))
+                virtio_disk->disks[i].readonly = 1;
+            else if (!strcmp(disk_opt, "rw"))
+                virtio_disk->disks[i].readonly = 0;
+            else {
+                fprintf(stderr, "vdisk: failed to parse \"%s\" disk option\n",
+                        disk_opt);
+                rc = 1;
+            }
+            free(disk_opt);
+
+            if (rc) goto out;
+        }
+    } else {
+        fprintf(stderr, "Unknown string \"%s\" in vdisk spec\n", token);
+        rc = 1; goto out;
+    }
+
+    rc = 0;
+
+out:
+    libxl_string_list_dispose(&disks);
+    return rc;
+}
+
+static void parse_virtio_disk_list(const XLU_Config *config,
+                            libxl_domain_config *d_config)
+{
+    XLU_ConfigList *virtio_disks;
+    const char *item;
+    char *buf = NULL;
+    int rc;
+
+    if (!xlu_cfg_get_list (config, "vdisk", &virtio_disks, 0, 0)) {
+        libxl_domain_build_info *b_info = &d_config->b_info;
+        int entry = 0;
+
+        /* XXX Remove an extra property */
+        libxl_defbool_setdefault(&b_info->arch_arm.virtio, false);
+        if (!libxl_defbool_val(b_info->arch_arm.virtio)) {
+            fprintf(stderr, "Virtio device requires Virtio property to be set\n");
+            exit(EXIT_FAILURE);
+        }
+
+        while ((item = xlu_cfg_get_listitem(virtio_disks, entry)) != NULL) {
+            libxl_device_virtio_disk *virtio_disk;
+            char *p;
+
+            virtio_disk = ARRAY_EXTEND_INIT(d_config->virtio_disks,
+                                            d_config->num_virtio_disks,
+                                            libxl_device_virtio_disk_init);
+
+            buf = strdup(item);
+
+            p = strtok (buf, ",");
+            while (p != NULL)
+            {
+                while (*p == ' ') p++;
+
+                rc = parse_virtio_disk_config(virtio_disk, p);
+                if (rc) goto out;
+
+                p = strtok (NULL, ",");
+            }
+
+            entry++;
+
+            if (virtio_disk->num_disks == 0) {
+                fprintf(stderr, "At least one virtio disk should be specified\n");
+                rc = 1; goto out;
+            }
+        }
+    }
+
+    rc = 0;
+
+out:
+    free(buf);
+    if (rc) exit(EXIT_FAILURE);
+}
+
 void parse_config_data(const char *config_source,
                        const char *config_data,
                        int config_len,
@@ -2734,6 +2848,7 @@ skip_usbdev:
     }
 
     parse_vkb_list(config, d_config);
+    parse_virtio_disk_list(config, d_config);
 
     xlu_cfg_get_defbool(config, "xend_suspend_evtchn_compat",
                         &c_info->xend_suspend_evtchn_compat, 0);
diff --git a/tools/xl/xl_virtio_disk.c b/tools/xl/xl_virtio_disk.c
new file mode 100644
index 0000000000..808a7daca7
--- /dev/null
+++ b/tools/xl/xl_virtio_disk.c
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2020 EPAM Systems Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; version 2.1 only. with the special
+ * exception on linking described in file LICENSE.
+ *
+ * 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 Lesser General Public License for more details.
+ */
+
+#include <stdlib.h>
+
+#include <libxl.h>
+#include <libxl_utils.h>
+#include <libxlutil.h>
+
+#include "xl.h"
+#include "xl_utils.h"
+#include "xl_parse.h"
+
+int main_virtio_diskattach(int argc, char **argv)
+{
+    return 0;
+}
+
+int main_virtio_disklist(int argc, char **argv)
+{
+   return 0;
+}
+
+int main_virtio_diskdetach(int argc, char **argv)
+{
+    return 0;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */