From: David Woodhouse <dwmw@xxxxxxxxxxxx>
There's no need to force the user to assign a vdev. We can automatically
assign one, starting at xvda and searching until we find the first disk
name that's unused.
This means we can now allow '-drive if=xen,file=xxx' to work without an
explicit separate -driver argument, just like if=virtio.
Rip out the legacy handling from the xenpv machine, which was scribbling
over any disks configured by the toolstack, and didn't work with anything
but raw images.
Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
Acked-by: Kevin Wolf <kwolf@xxxxxxxxxx>
Reviewed-by: Paul Durrant <paul@xxxxxxx>
---
blockdev.c | 15 +++-
hw/block/xen-block.c | 118 ++++++++++++++++++++++++++--
hw/xen/xen_devconfig.c | 28 -------
hw/xenpv/xen_machine_pv.c | 9 ---
include/hw/xen/xen-legacy-backend.h | 1 -
5 files changed, 125 insertions(+), 46 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 1517dc6210..e9b7e38dc4 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -255,13 +255,13 @@ void drive_check_orphaned(void)
* Ignore default drives, because we create certain default
* drives unconditionally, then leave them unclaimed. Not the
* users fault.
- * Ignore IF_VIRTIO, because it gets desugared into -device,
- * so we can leave failing to -device.
+ * Ignore IF_VIRTIO or IF_XEN, because it gets desugared into
+ * -device, so we can leave failing to -device.
* Ignore IF_NONE, because leaving unclaimed IF_NONE remains
* available for device_add is a feature.
*/
if (dinfo->is_default || dinfo->type == IF_VIRTIO
- || dinfo->type == IF_NONE) {
+ || dinfo->type == IF_XEN || dinfo->type == IF_NONE) {
continue;
}
if (!blk_get_attached_dev(blk)) {
@@ -977,6 +977,15 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_type,
qemu_opt_set(devopts, "driver", "virtio-blk", &error_abort);
qemu_opt_set(devopts, "drive", qdict_get_str(bs_opts, "id"),
&error_abort);
+ } else if (type == IF_XEN) {
+ QemuOpts *devopts;
+ devopts = qemu_opts_create(qemu_find_opts("device"), NULL, 0,
+ &error_abort);
+ qemu_opt_set(devopts, "driver",
+ (media == MEDIA_CDROM) ? "xen-cdrom" : "xen-disk",
+ &error_abort);
+ qemu_opt_set(devopts, "drive", qdict_get_str(bs_opts, "id"),
+ &error_abort);
}
filename = qemu_opt_get(legacy_opts, "file");
diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c
index bfa53960c3..6d64ede94f 100644
--- a/hw/block/xen-block.c
+++ b/hw/block/xen-block.c
@@ -27,13 +27,119 @@
#include "sysemu/block-backend.h"
#include "sysemu/iothread.h"
#include "dataplane/xen-block.h"
+#include "hw/xen/interface/io/xs_wire.h"
#include "trace.h"
+#define XVDA_MAJOR 202
+#define XVDQ_MAJOR (1 << 20)
+#define XVDBGQCV_MAJOR ((1 << 21) - 1)
+#define HDA_MAJOR 3
+#define HDC_MAJOR 22
+#define SDA_MAJOR 8
+
+
+static int vdev_to_diskno(unsigned int vdev_nr)
+{
+ switch (vdev_nr >> 8) {
+ case XVDA_MAJOR:
+ case SDA_MAJOR:
+ return (vdev_nr >> 4) & 0x15;
+
+ case HDA_MAJOR:
+ return (vdev_nr >> 6) & 1;
+
+ case HDC_MAJOR:
+ return ((vdev_nr >> 6) & 1) + 2;
+
+ case XVDQ_MAJOR ... XVDBGQCV_MAJOR:
+ return (vdev_nr >> 8) & 0xfffff;
+
+ default:
+ return -1;
+ }
+}
+
+#define MAX_AUTO_VDEV 4096
+
+/*
+ * Find a free device name in the xvda → xvdfan range and set it in
+ * blockdev->props.vdev. Our definition of "free" is that there must
+ * be no other disk or partition with the same disk number.
+ *
+ * You are technically permitted to have all of hda, hda1, sda, sda1,
+ * xvda and xvda1 as *separate* PV block devices with separate backing
+ * stores. That doesn't make it a good idea. This code will skip xvda
+ * if *any* of those "conflicting" devices already exists.
+ *
+ * The limit of xvdfan (disk 4095) is fairly arbitrary just to avoid a
+ * stupidly sized bitmap, but Linux as of v6.6 doesn't support anything
+ * higher than that anyway.
+ */
+static bool xen_block_find_free_vdev(XenBlockDevice *blockdev, Error **errp)
+{
+ XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(blockdev)));
+ unsigned long used_devs[BITS_TO_LONGS(MAX_AUTO_VDEV)];
+ XenBlockVdev *vdev = &blockdev->props.vdev;
+ char fe_path[XENSTORE_ABS_PATH_MAX + 1];
+ char **existing_frontends;
+ unsigned int nr_existing = 0;
+ unsigned int vdev_nr;
+ int i, disk = 0;
+
+ snprintf(fe_path, sizeof(fe_path), "/local/domain/%u/device/vbd",
+ blockdev->xendev.frontend_id);
+
+ existing_frontends = qemu_xen_xs_directory(xenbus->xsh, XBT_NULL, fe_path,
+ &nr_existing);
+ if (!existing_frontends && errno != ENOENT) {
+ error_setg_errno(errp, errno, "cannot read %s", fe_path);
+ return false;
+ }
+
+ memset(used_devs, 0, sizeof(used_devs));
+ for (i = 0; i < nr_existing; i++) {
+ if (qemu_strtoui(existing_frontends[i], NULL, 10, &vdev_nr)) {
+ free(existing_frontends[i]);
+ continue;
+ }
+
+ free(existing_frontends[i]);
+
+ disk = vdev_to_diskno(vdev_nr);
+ if (disk < 0 || disk >= MAX_AUTO_VDEV) {
+ continue;
+ }
+
+ set_bit(disk, used_devs);
+ }
+ free(existing_frontends);
+
+ disk = find_first_zero_bit(used_devs, MAX_AUTO_VDEV);
+ if (disk == MAX_AUTO_VDEV) {
+ error_setg(errp, "cannot find device vdev for block device");
+ return false;
+ }
+
+ vdev->type = XEN_BLOCK_VDEV_TYPE_XVD;
+ vdev->partition = 0;
+ vdev->disk = disk;
+ if (disk < (1 << 4)) {
+ vdev->number = (XVDA_MAJOR << 8) | (disk << 4);
+ } else {
+ vdev->number = (XVDQ_MAJOR << 8) | (disk << 8);
+ }
+ return true;
+}
+
static char *xen_block_get_name(XenDevice *xendev, Error **errp)
{
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
XenBlockVdev *vdev = &blockdev->props.vdev;
+ if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID &&
+ !xen_block_find_free_vdev(blockdev, errp)) {
+ return NULL;
+ }
return g_strdup_printf("%lu", vdev->number);
}
@@ -482,10 +588,10 @@ static void xen_block_set_vdev(Object *obj, Visitor *v, const char *name,
case XEN_BLOCK_VDEV_TYPE_DP:
case XEN_BLOCK_VDEV_TYPE_XVD:
if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
- vdev->number = (202 << 8) | (vdev->disk << 4) |
+ vdev->number = (XVDA_MAJOR << 8) | (vdev->disk << 4) |
vdev->partition;
} else if (vdev->disk < (1 << 20) && vdev->partition < (1 << 8)) {
- vdev->number = (1 << 28) | (vdev->disk << 8) |
+ vdev->number = (XVDQ_MAJOR << 8) | (vdev->disk << 8) |
vdev->partition;
} else {
goto invalid;
@@ -495,10 +601,11 @@ static void xen_block_set_vdev(Object *obj, Visitor *v, const char *name,
case XEN_BLOCK_VDEV_TYPE_HD:
if ((vdev->disk == 0 || vdev->disk == 1) &&
vdev->partition < (1 << 6)) {
- vdev->number = (3 << 8) | (vdev->disk << 6) | vdev->partition;
+ vdev->number = (HDA_MAJOR << 8) | (vdev->disk << 6) |
+ vdev->partition;
} else if ((vdev->disk == 2 || vdev->disk == 3) &&
vdev->partition < (1 << 6)) {
- vdev->number = (22 << 8) | ((vdev->disk - 2) << 6) |
+ vdev->number = (HDC_MAJOR << 8) | ((vdev->disk - 2) << 6) |
vdev->partition;
} else {
goto invalid;
@@ -507,7 +614,8 @@ static void xen_block_set_vdev(Object *obj, Visitor *v, const char *name,
case XEN_BLOCK_VDEV_TYPE_SD:
if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
- vdev->number = (8 << 8) | (vdev->disk << 4) | vdev->partition;
+ vdev->number = (SDA_MAJOR << 8) | (vdev->disk << 4) |
+ vdev->partition;
} else {
goto invalid;
}
diff --git a/hw/xen/xen_devconfig.c b/hw/xen/xen_devconfig.c
index 9b7304e544..3f77c675c6 100644
--- a/hw/xen/xen_devconfig.c
+++ b/hw/xen/xen_devconfig.c
@@ -46,34 +46,6 @@ static int xen_config_dev_all(char *fe, char *be)
/* ------------------------------------------------------------- */
-int xen_config_dev_blk(DriveInfo *disk)
-{
- char fe[256], be[256], device_name[32];
- int vdev = 202 * 256 + 16 * disk->unit;
- int cdrom = disk->media_cd;
- const char *devtype = cdrom ? "cdrom" : "disk";
- const char *mode = cdrom ? "r" : "w";
- const char *filename = qemu_opt_get(disk->opts, "file");
-
- snprintf(device_name, sizeof(device_name), "xvd%c", 'a' + disk->unit);
- xen_pv_printf(NULL, 1, "config disk %d [%s]: %s\n",
- disk->unit, device_name, filename);
- xen_config_dev_dirs("vbd", "qdisk", vdev, fe, be, sizeof(fe));
-
- /* frontend */
- xenstore_write_int(fe, "virtual-device", vdev);
- xenstore_write_str(fe, "device-type", devtype);
-
- /* backend */
- xenstore_write_str(be, "dev", device_name);
- xenstore_write_str(be, "type", "file");
- xenstore_write_str(be, "params", filename);
- xenstore_write_str(be, "mode", mode);
-
- /* common stuff */
- return xen_config_dev_all(fe, be);
-}
-
int xen_config_dev_nic(NICInfo *nic)
{
char fe[256], be[256];
diff --git a/hw/xenpv/xen_machine_pv.c b/hw/xenpv/xen_machine_pv.c
index 17cda5ec13..1533f5dfb4 100644
--- a/hw/xenpv/xen_machine_pv.c
+++ b/hw/xenpv/xen_machine_pv.c
@@ -32,7 +32,6 @@
static void xen_init_pv(MachineState *machine)
{
- DriveInfo *dinfo;
int i;
setup_xen_backend_ops();
@@ -64,14 +63,6 @@ static void xen_init_pv(MachineState *machine)
vga_interface_created = true;
}
- /* configure disks */
- for (i = 0; i < 16; i++) {
- dinfo = drive_get(IF_XEN, 0, i);
- if (!dinfo)
- continue;
- xen_config_dev_blk(dinfo);
- }
-
/* configure nics */
for (i = 0; i < nb_nics; i++) {
if (!nd_table[i].model || 0 != strcmp(nd_table[i].model, "xen"))
diff --git a/include/hw/xen/xen-legacy-backend.h b/include/hw/xen/xen-legacy-backend.h
index 6c307c5f2c..fc42146bc2 100644
--- a/include/hw/xen/xen-legacy-backend.h
+++ b/include/hw/xen/xen-legacy-backend.h
@@ -81,7 +81,6 @@ extern struct XenDevOps xen_usb_ops; /* xen-usb.c */
/* configuration (aka xenbus setup) */
void xen_config_cleanup(void);
-int xen_config_dev_blk(DriveInfo *disk);
int xen_config_dev_nic(NICInfo *nic);
int xen_config_dev_vfb(int vdev, const char *type);
int xen_config_dev_vkbd(int vdev);
--
2.41.0
