[PATCH] efi_loader: expand disk device names with drive details

[Heinrich Schuchardt]

On 4/20/26 09:28, Padmarao Begari wrote:
> Increase the boot menu device name buffer so we can append extra
> metadata. Append the disk capacity and trimmed vendor/product strings
> to the device name so users can differentiate drives in the EFI boot
> menu. Also tighten the parameter validation and pull in linux/string.h
> for strl* helpers.
> 
> For example, the U-Boot boot menu now shows entries such as:
> 
>      usb 0 (29.7 GiB, Generic Ultra HS-COMBO)
>      usb 1 (28.6 GiB, USB SanDisk 3.2Gen1)
>      scsi 0 (1 GiB, MICRON MT064GBCAV1U31AA)

Adding a descriptive text looks like a good idea to me. I am just not 
sure if with the patch we are showing the relevant information.

nvme 0 (953 GiB, SKHynix_HFS001TEM4X169N)
nvme 1 (953 GiB, SKHynix_HFS001TEM4X169N)
nvme 2 (953 GiB, SKHynix_HFS001TEM4X169N)

I would not know if these are 3 namespaces on the same drive or 
different drives.

EDK II MdeModulePkg/Library/UefiBootManagerLib/BmBootDescription.c, 
BmGetNvmeDescription() sends ADMIN_IDENTIFY command to the NVME 
controller to get the model and serial number.

The EDK II description for NVMe namespaces contains:

* model
* serial number
* namespace ID

This information is sufficient to identify what the boot entry relates to.

Another example:

host 0 (64 MiB, U-Boot hostfile)
host 1 (64 MiB, U-Boot hostfile)

Wouldn't the user need the mounted file here?

> 
> Signed-off-by: Padmarao Begari <padmarao.begari at amd.com>
> ---
>   include/efi_loader.h      |  2 +-
>   lib/efi_loader/efi_disk.c | 86 ++++++++++++++++++++++++++++++++++++++-
>   2 files changed, 85 insertions(+), 3 deletions(-)
> 
> diff --git a/include/efi_loader.h b/include/efi_loader.h
> index 3a4d502631c..b6065cfdab7 100644
> --- a/include/efi_loader.h
> +++ b/include/efi_loader.h
> @@ -290,7 +290,7 @@ const char *__efi_nesting_dec(void);
>   #endif
>   
>   /* max bootmenu title size for volume selection */
> -#define BOOTMENU_DEVICE_NAME_MAX 16
> +#define BOOTMENU_DEVICE_NAME_MAX 128

If your terminal is only 80 characters wide and you print 128 character 
strings, they will overflow into the next line. This should be avoided.

Some displays may even have less than 80 characters per line.

Please, check the usage in the boot menu and the eficonfig command.

>   
>   /* Key identifying current memory map */
>   extern efi_uintn_t efi_memory_map_key;
> diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
> index f8a57539ec6..e0b613065d5 100644
> --- a/lib/efi_loader/efi_disk.c
> +++ b/lib/efi_loader/efi_disk.c
> @@ -19,6 +19,8 @@
>   #include <log.h>
>   #include <part.h>
>   #include <malloc.h>
> +#include <linux/sizes.h>
> +#include <linux/string.h>
>   
>   struct efi_system_partition efi_system_partition = {
>   	.uclass_id = UCLASS_INVALID,
> @@ -813,9 +815,87 @@ int efi_disk_remove(void *ctx, struct event *event)
>   
>   }
>   
> +#define EFI_DISK_SIZE_TENTHS		10
> +#define EFI_DISK_CAPACITY_STR_MAX	sizeof("17179869183.9 GiB")
> +#define EFI_DISK_DETAIL_MAX		(BLK_VEN_SIZE + BLK_PRD_SIZE + \
> +					 EFI_DISK_CAPACITY_STR_MAX + \
> +					 sizeof(" (, )"))
> +
> +/**
> + * efi_disk_append_detail() - append capacity and vendor info to a device label
> + *
> + * Appends a " (size, vendor product)" suffix to @buf when the block
> + * descriptor carries readable capacity or identification strings.
> + *
> + * @desc:	block device descriptor
> + * @buf:	label buffer to append to (already contains base name)
> + * @size:	total size of @buf in bytes
> + */
> +static void efi_disk_append_detail(const struct blk_desc *desc,
> +				   char *buf, int size)
> +{
> +	u64 capacity = (u64)desc->lba * desc->blksz;
> +	char capacity_str[EFI_DISK_CAPACITY_STR_MAX];
> +	char vendor_buf[BLK_VEN_SIZE + 1];
> +	char product_buf[BLK_PRD_SIZE + 1];
> +	char detail[EFI_DISK_DETAIL_MAX];
> +	char *vendor, *product;
> +
> +	capacity_str[0] = '\0';
> +
> +	if (capacity >= SZ_1G) {

Please, consider using print_size(capacity, "").

Best regards

Heinrich

> +		u64 gib = capacity / SZ_1G;
> +		u64 tenths = ((capacity % SZ_1G) * EFI_DISK_SIZE_TENTHS) /
> +			     SZ_1G;
> +
> +		if (tenths)
> +			snprintf(capacity_str, sizeof(capacity_str),
> +				 "%llu.%u GiB", gib,
> +				 (unsigned int)tenths);
> +		else
> +			snprintf(capacity_str, sizeof(capacity_str),
> +				 "%llu GiB", gib);
> +	} else if (capacity >= SZ_1M) {
> +		snprintf(capacity_str, sizeof(capacity_str), "%llu MiB",
> +			 capacity / SZ_1M);
> +	} else if (capacity >= SZ_1K) {
> +		snprintf(capacity_str, sizeof(capacity_str), "%llu KiB",
> +			 capacity / SZ_1K);
> +	} else if (capacity) {
> +		snprintf(capacity_str, sizeof(capacity_str), "%llu B", capacity);
> +	}
> +
> +	strlcpy(vendor_buf, desc->vendor, sizeof(vendor_buf));
> +	strlcpy(product_buf, desc->product, sizeof(product_buf));
> +	vendor = strim(vendor_buf);
> +	product = strim(product_buf);
> +
> +	if (!capacity_str[0] && !vendor[0] && !product[0])
> +		return;
> +
> +	detail[0] = '\0';
> +	strlcat(detail, " (", sizeof(detail));
> +	if (capacity_str[0]) {
> +		strlcat(detail, capacity_str, sizeof(detail));
> +		if (vendor[0] || product[0])
> +			strlcat(detail, ", ", sizeof(detail));
> +	}
> +	strlcat(detail, vendor, sizeof(detail));
> +	if (vendor[0] && product[0])
> +		strlcat(detail, " ", sizeof(detail));
> +	strlcat(detail, product, sizeof(detail));
> +	strlcat(detail, ")", sizeof(detail));
> +
> +	strlcat(buf, detail, size);
> +}
> +
>   /**
>    * efi_disk_get_device_name() - get U-Boot device name associated with EFI handle
>    *
> + * Fills @buf with a human-readable label such as "mmc 0 (7.5 GiB, SanDisk
> + * AJTD4R)". Capacity and trimmed vendor/product strings are appended when
> + * available.
> + *
>    * @handle:	pointer to the EFI handle
>    * @buf:	pointer to the buffer to store the string
>    * @size:	size of buffer
> @@ -833,7 +913,7 @@ efi_status_t efi_disk_get_device_name(const efi_handle_t handle, char *buf, int
>   	bool is_partition = false;
>   	struct disk_part *part_data;
>   
> -	if (!handle || !buf || !size)
> +	if (!handle || !buf || size <= 0)
>   		return EFI_INVALID_PARAMETER;
>   
>   	dev = handle->dev;
> @@ -858,9 +938,11 @@ efi_status_t efi_disk_get_device_name(const efi_handle_t handle, char *buf, int
>   		count = snprintf(buf, size, "%s %d", if_typename, diskid);
>   	}
>   
> -	if (count < 0 || (count + 1) > size)
> +	if (count < 0 || count >= size)
>   		return EFI_INVALID_PARAMETER;
>   
> +	efi_disk_append_detail(desc, buf, size);
> +
>   	return EFI_SUCCESS;
>   }
>