diff options
Diffstat (limited to 'hw/block/xen-block.c')
| -rw-r--r-- | hw/block/xen-block.c | 128 |
1 files changed, 120 insertions, 8 deletions
diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c index a07cd7eb5d..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); } @@ -115,9 +221,13 @@ static void xen_block_connect(XenDevice *xendev, Error **errp) return; } - if (xen_device_frontend_scanf(xendev, "protocol", "%ms", - &str) != 1) { - protocol = BLKIF_PROTOCOL_NATIVE; + if (xen_device_frontend_scanf(xendev, "protocol", "%ms", &str) != 1) { + /* x86 defaults to the 32-bit protocol even for 64-bit guests. */ + if (object_dynamic_cast(OBJECT(qdev_get_machine()), "x86-machine")) { + protocol = BLKIF_PROTOCOL_X86_32; + } else { + protocol = BLKIF_PROTOCOL_NATIVE; + } } else { if (strcmp(str, XEN_IO_PROTO_ABI_X86_32) == 0) { protocol = BLKIF_PROTOCOL_X86_32; @@ -478,10 +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; @@ -491,10 +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; @@ -503,7 +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; } |