[PATCH 3/8] blk: blkmap: Add basic infrastructure
Tobias Waldekranz
tobias at waldekranz.com
Wed Feb 1 19:10:11 CET 2023
blkmaps are loosely modeled on Linux's device mapper subsystem. The
basic idea is that you can create virtual block devices whose blocks
can be backed by a plethora of sources that are user configurable.
This change just adds the basic infrastructure for creating and
removing blkmap devices. Subsequent changes will extend this to add
support for actual mappings.
Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
---
MAINTAINERS | 6 +
disk/part.c | 1 +
drivers/block/Kconfig | 18 ++
drivers/block/Makefile | 1 +
drivers/block/blk-uclass.c | 1 +
drivers/block/blkmap.c | 275 +++++++++++++++++++++++++++++++
include/blkmap.h | 15 ++
include/dm/uclass-id.h | 1 +
include/efi_loader.h | 4 +
lib/efi_loader/efi_device_path.c | 30 ++++
10 files changed, 352 insertions(+)
create mode 100644 drivers/block/blkmap.c
create mode 100644 include/blkmap.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 3e8e193ecc..28a34231bf 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -786,6 +786,12 @@ M: Alper Nebi Yasak <alpernebiyasak at gmail.com>
S: Maintained
F: tools/binman/
+BLKMAP
+M: Tobias Waldekranz <tobias at waldekranz.com>
+S: Maintained
+F: drivers/block/blkmap.c
+F: include/blkmap.h
+
BOOTDEVICE
M: Simon Glass <sjg at chromium.org>
S: Maintained
diff --git a/disk/part.c b/disk/part.c
index d449635254..35300df590 100644
--- a/disk/part.c
+++ b/disk/part.c
@@ -140,6 +140,7 @@ void dev_print(struct blk_desc *dev_desc)
case UCLASS_NVME:
case UCLASS_PVBLOCK:
case UCLASS_HOST:
+ case UCLASS_BLKMAP:
printf ("Vendor: %s Rev: %s Prod: %s\n",
dev_desc->vendor,
dev_desc->revision,
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index e95da48bdc..5a1aeb3d2b 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -67,6 +67,24 @@ config BLOCK_CACHE
it will prevent repeated reads from directory structures and other
filesystem data structures.
+config BLKMAP
+ bool "Composable virtual block devices (blkmap)"
+ depends on BLK
+ help
+ Create virtual block devices that are backed by various sources,
+ e.g. RAM, or parts of an existing block device. Though much more
+ rudimentary, it borrows a lot of ideas from Linux's device mapper
+ subsystem.
+
+ Example use-cases:
+ - Treat a region of RAM as a block device, i.e. a RAM disk. This let's
+ you extract files from filesystem images stored in RAM (perhaps as a
+ result of a TFTP transfer).
+ - Create a virtual partition on an existing device. This let's you
+ access filesystems that aren't stored at an exact partition
+ boundary. A common example is a filesystem image embedded in an FIT
+ image.
+
config SPL_BLOCK_CACHE
bool "Use block device cache in SPL"
depends on SPL_BLK
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index f12447d78d..a161d145fd 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_IDE) += ide.o
endif
obj-$(CONFIG_SANDBOX) += sandbox.o host-uclass.o host_dev.o
obj-$(CONFIG_$(SPL_TPL_)BLOCK_CACHE) += blkcache.o
+obj-$(CONFIG_BLKMAP) += blkmap.o
obj-$(CONFIG_EFI_MEDIA) += efi-media-uclass.o
obj-$(CONFIG_EFI_MEDIA_SANDBOX) += sb_efi_media.o
diff --git a/drivers/block/blk-uclass.c b/drivers/block/blk-uclass.c
index c69fc4d518..cb73faaeda 100644
--- a/drivers/block/blk-uclass.c
+++ b/drivers/block/blk-uclass.c
@@ -32,6 +32,7 @@ static struct {
{ UCLASS_EFI_LOADER, "efiloader" },
{ UCLASS_VIRTIO, "virtio" },
{ UCLASS_PVBLOCK, "pvblock" },
+ { UCLASS_BLKMAP, "blkmap" },
};
static enum uclass_id uclass_name_to_iftype(const char *uclass_idname)
diff --git a/drivers/block/blkmap.c b/drivers/block/blkmap.c
new file mode 100644
index 0000000000..a6ba07404c
--- /dev/null
+++ b/drivers/block/blkmap.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2023 Addiva Elektronik
+ * Author: Tobias Waldekranz <tobias at waldekranz.com>
+ */
+
+#include <common.h>
+#include <blk.h>
+#include <blkmap.h>
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <dm/root.h>
+#include <malloc.h>
+#include <part.h>
+
+struct blkmap;
+
+struct blkmap_slice {
+ struct list_head node;
+
+ lbaint_t blknr;
+ lbaint_t blkcnt;
+
+ ulong (*read)(struct blkmap *bm, struct blkmap_slice *bms,
+ lbaint_t blknr, lbaint_t blkcnt, void *buffer);
+ ulong (*write)(struct blkmap *bm, struct blkmap_slice *bms,
+ lbaint_t blknr, lbaint_t blkcnt, const void *buffer);
+ void (*destroy)(struct blkmap *bm, struct blkmap_slice *bms);
+};
+
+struct blkmap {
+ struct udevice *dev;
+ struct list_head slices;
+};
+
+static bool blkmap_slice_contains(struct blkmap_slice *bms, lbaint_t blknr)
+{
+ return (blknr >= bms->blknr) && (blknr < (bms->blknr + bms->blkcnt));
+}
+
+static bool blkmap_slice_available(struct blkmap *bm, struct blkmap_slice *new)
+{
+ struct blkmap_slice *bms;
+ lbaint_t first, last;
+
+ first = new->blknr;
+ last = new->blknr + new->blkcnt - 1;
+
+ list_for_each_entry(bms, &bm->slices, node) {
+ if (blkmap_slice_contains(bms, first) ||
+ blkmap_slice_contains(bms, last) ||
+ blkmap_slice_contains(new, bms->blknr) ||
+ blkmap_slice_contains(new, bms->blknr + bms->blkcnt - 1))
+ return false;
+ }
+
+ return true;
+}
+
+static struct blkmap *blkmap_from_devnum(int devnum)
+{
+ struct udevice *dev;
+ int err;
+
+ err = blk_find_device(UCLASS_BLKMAP, devnum, &dev);
+
+ return err ? NULL : dev_get_priv(dev);
+}
+
+static int blkmap_add(struct blkmap *bm, struct blkmap_slice *new)
+{
+ struct blk_desc *bd = dev_get_uclass_plat(bm->dev);
+ struct list_head *insert = &bm->slices;
+ struct blkmap_slice *bms;
+
+ if (!blkmap_slice_available(bm, new))
+ return -EBUSY;
+
+ list_for_each_entry(bms, &bm->slices, node) {
+ if (bms->blknr < new->blknr)
+ continue;
+
+ insert = &bms->node;
+ break;
+ }
+
+ list_add_tail(&new->node, insert);
+
+ /* Disk might have grown, update the size */
+ bms = list_last_entry(&bm->slices, struct blkmap_slice, node);
+ bd->lba = bms->blknr + bms->blkcnt;
+ return 0;
+}
+
+static struct udevice *blkmap_root(void)
+{
+ static struct udevice *dev;
+ int err;
+
+ if (dev)
+ return dev;
+
+ err = device_bind_driver(dm_root(), "blkmap_root", "blkmap", &dev);
+ if (err)
+ return NULL;
+
+ err = device_probe(dev);
+ if (err) {
+ device_unbind(dev);
+ return NULL;
+ }
+
+ return dev;
+}
+
+int blkmap_create(int devnum)
+{
+ struct udevice *root;
+ struct blk_desc *bd;
+ struct blkmap *bm;
+ int err;
+
+ if (devnum >= 0 && blkmap_from_devnum(devnum))
+ return -EBUSY;
+
+ root = blkmap_root();
+ if (!root)
+ return -ENODEV;
+
+ bm = calloc(1, sizeof(*bm));
+ if (!bm)
+ return -ENOMEM;
+
+ err = blk_create_devicef(root, "blkmap_blk", "blk", UCLASS_BLKMAP,
+ devnum, 512, 0, &bm->dev);
+ if (err)
+ goto err_free;
+
+ bd = dev_get_uclass_plat(bm->dev);
+
+ /* EFI core isn't keen on zero-sized disks, so we lie. This is
+ * updated with the correct size once the user adds a
+ * mapping.
+ */
+ bd->lba = 1;
+
+ dev_set_priv(bm->dev, bm);
+ INIT_LIST_HEAD(&bm->slices);
+
+ err = blk_probe_or_unbind(bm->dev);
+ if (err)
+ goto err_remove;
+
+ return bd->devnum;
+
+err_remove:
+ device_remove(bm->dev, DM_REMOVE_NORMAL);
+err_free:
+ free(bm);
+ return err;
+}
+
+int blkmap_destroy(int devnum)
+{
+ struct blkmap_slice *bms, *tmp;
+ struct blkmap *bm;
+ int err;
+
+ bm = blkmap_from_devnum(devnum);
+ if (!bm)
+ return -ENODEV;
+
+ err = device_remove(bm->dev, DM_REMOVE_NORMAL);
+ if (err)
+ return err;
+
+ err = device_unbind(bm->dev);
+ if (err)
+ return err;
+
+ list_for_each_entry_safe(bms, tmp, &bm->slices, node) {
+ list_del(&bms->node);
+ free(bms);
+ }
+
+ free(bm);
+ return 0;
+}
+
+static ulong blkmap_read_slice(struct blkmap *bm, struct blkmap_slice *bms,
+ lbaint_t blknr, lbaint_t blkcnt, void *buffer)
+{
+ lbaint_t nr, cnt;
+
+ nr = blknr - bms->blknr;
+ cnt = (blkcnt < bms->blkcnt) ? blkcnt : bms->blkcnt;
+ return bms->read(bm, bms, nr, cnt, buffer);
+}
+
+static ulong blkmap_read(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
+ void *buffer)
+{
+ struct blk_desc *bd = dev_get_uclass_plat(dev);
+ struct blkmap *bm = dev_get_priv(dev);
+ struct blkmap_slice *bms;
+ lbaint_t cnt, total = 0;
+
+ list_for_each_entry(bms, &bm->slices, node) {
+ if (!blkmap_slice_contains(bms, blknr))
+ continue;
+
+ cnt = blkmap_read_slice(bm, bms, blknr, blkcnt, buffer);
+ blknr += cnt;
+ blkcnt -= cnt;
+ buffer += cnt << bd->log2blksz;
+ total += cnt;
+ }
+
+ return total;
+}
+
+static ulong blkmap_write_slice(struct blkmap *bm, struct blkmap_slice *bms,
+ lbaint_t blknr, lbaint_t blkcnt,
+ const void *buffer)
+{
+ lbaint_t nr, cnt;
+
+ nr = blknr - bms->blknr;
+ cnt = (blkcnt < bms->blkcnt) ? blkcnt : bms->blkcnt;
+ return bms->write(bm, bms, nr, cnt, buffer);
+}
+
+static ulong blkmap_write(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
+ const void *buffer)
+{
+ struct blk_desc *bd = dev_get_uclass_plat(dev);
+ struct blkmap *bm = dev_get_priv(dev);
+ struct blkmap_slice *bms;
+ lbaint_t cnt, total = 0;
+
+ list_for_each_entry(bms, &bm->slices, node) {
+ if (!blkmap_slice_contains(bms, blknr))
+ continue;
+
+ cnt = blkmap_write_slice(bm, bms, blknr, blkcnt, buffer);
+ blknr += cnt;
+ blkcnt -= cnt;
+ buffer += cnt << bd->log2blksz;
+ total += cnt;
+ }
+
+ return total;
+}
+
+static const struct blk_ops blkmap_ops = {
+ .read = blkmap_read,
+ .write = blkmap_write,
+};
+
+U_BOOT_DRIVER(blkmap_blk) = {
+ .name = "blkmap_blk",
+ .id = UCLASS_BLK,
+ .ops = &blkmap_ops,
+};
+
+U_BOOT_DRIVER(blkmap_root) = {
+ .name = "blkmap_root",
+ .id = UCLASS_BLKMAP,
+};
+
+UCLASS_DRIVER(blkmap) = {
+ .id = UCLASS_BLKMAP,
+ .name = "blkmap",
+};
diff --git a/include/blkmap.h b/include/blkmap.h
new file mode 100644
index 0000000000..37c0c31c3f
--- /dev/null
+++ b/include/blkmap.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2023 Addiva Elektronik
+ * Author: Tobias Waldekranz <tobias at waldekranz.com>
+ */
+
+#ifndef _BLKMAP_H
+#define _BLKMAP_H
+
+#include <stdbool.h>
+
+int blkmap_create(int devnum);
+int blkmap_destroy(int devnum);
+
+#endif /* _BLKMAP_H */
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 33e43c20db..576237b954 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -37,6 +37,7 @@ enum uclass_id {
UCLASS_AUDIO_CODEC, /* Audio codec with control and data path */
UCLASS_AXI, /* AXI bus */
UCLASS_BLK, /* Block device */
+ UCLASS_BLKMAP, /* Composable virtual block device */
UCLASS_BOOTCOUNT, /* Bootcount backing store */
UCLASS_BOOTDEV, /* Boot device for locating an OS to boot */
UCLASS_BOOTMETH, /* Bootmethod for booting an OS */
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 4560b0d04c..59687f44de 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -134,6 +134,10 @@ static inline efi_status_t efi_launch_capsules(void)
#define U_BOOT_GUID \
EFI_GUID(0xe61d73b9, 0xa384, 0x4acc, \
0xae, 0xab, 0x82, 0xe8, 0x28, 0xf3, 0x62, 0x8b)
+/* GUID used as root for blkmap devices */
+#define U_BOOT_BLKMAP_DEV_GUID \
+ EFI_GUID(0x4cad859d, 0xd644, 0x42ff, \
+ 0x87, 0x0b, 0xc0, 0x2e, 0xac, 0x05, 0x58, 0x63)
/* GUID used as host device on sandbox */
#define U_BOOT_HOST_DEV_GUID \
EFI_GUID(0xbbe4e671, 0x5773, 0x4ea1, \
diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
index 3b267b713e..4b4c96bc2e 100644
--- a/lib/efi_loader/efi_device_path.c
+++ b/lib/efi_loader/efi_device_path.c
@@ -21,6 +21,9 @@
#include <asm-generic/unaligned.h>
#include <linux/compat.h> /* U16_MAX */
+#ifdef CONFIG_BLKMAP
+const efi_guid_t efi_guid_blkmap_dev = U_BOOT_BLKMAP_DEV_GUID;
+#endif
#ifdef CONFIG_SANDBOX
const efi_guid_t efi_guid_host_dev = U_BOOT_HOST_DEV_GUID;
#endif
@@ -573,6 +576,16 @@ __maybe_unused static unsigned int dp_size(struct udevice *dev)
*/
return dp_size(dev->parent)
+ sizeof(struct efi_device_path_vendor) + 1;
+#endif
+#ifdef CONFIG_BLKMAP
+ case UCLASS_BLKMAP:
+ /*
+ * blkmap devices will be represented as a vendor
+ * device node with an extra byte for the device
+ * number.
+ */
+ return dp_size(dev->parent)
+ + sizeof(struct efi_device_path_vendor) + 1;
#endif
default:
return dp_size(dev->parent);
@@ -631,6 +644,23 @@ __maybe_unused static void *dp_fill(void *buf, struct udevice *dev)
#endif
case UCLASS_BLK:
switch (dev->parent->uclass->uc_drv->id) {
+#ifdef CONFIG_BLKMAP
+ case UCLASS_BLKMAP: {
+ struct efi_device_path_vendor *dp;
+ struct blk_desc *desc = dev_get_uclass_plat(dev);
+
+ dp_fill(buf, dev->parent);
+ dp = buf;
+ ++dp;
+ dp->dp.type = DEVICE_PATH_TYPE_HARDWARE_DEVICE;
+ dp->dp.sub_type = DEVICE_PATH_SUB_TYPE_VENDOR;
+ dp->dp.length = sizeof(*dp) + 1;
+ memcpy(&dp->guid, &efi_guid_blkmap_dev,
+ sizeof(efi_guid_t));
+ dp->vendor_data[0] = desc->devnum;
+ return &dp->vendor_data[1];
+ }
+#endif
#ifdef CONFIG_SANDBOX
case UCLASS_HOST: {
/* stop traversing parents at this point: */
--
2.34.1
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