Index: efiblock.c
===================================================================
RCS file: /cvsroot/src/sys/stand/efiboot/efiblock.c,v
retrieving revision 1.18
diff -p -u -r1.18 efiblock.c
--- efiblock.c	30 Oct 2021 11:18:51 -0000	1.18
+++ efiblock.c	23 Apr 2022 18:28:00 -0000
@@ -129,20 +129,21 @@ efi_block_do_read_blockio(struct efi_blo
 	EFI_STATUS status;
 	EFI_LBA lba_start, lba_end;
 	UINT64 blkbuf_offset;
-	UINT64 blkbuf_size;
+	UINT64 blkbuf_size, alloc_size;
 
 	lba_start = off / bdev->bio->Media->BlockSize;
-	lba_end = (off + bufsize + bdev->bio->Media->BlockSize - 1) /
-	    bdev->bio->Media->BlockSize;
+	lba_end = (off + bufsize - 1) / bdev->bio->Media->BlockSize;
 	blkbuf_offset = off % bdev->bio->Media->BlockSize;
-	blkbuf_size = (lba_end - lba_start) * bdev->bio->Media->BlockSize;
+	blkbuf_size = (lba_end - lba_start + 1) * bdev->bio->Media->BlockSize;
+
+	alloc_size = blkbuf_size;
 	if (bdev->bio->Media->IoAlign > 1) {
-		blkbuf_size = (blkbuf_size + bdev->bio->Media->IoAlign - 1) /
+		alloc_size = (blkbuf_size + bdev->bio->Media->IoAlign - 1) /
 		    bdev->bio->Media->IoAlign *
 		    bdev->bio->Media->IoAlign;
 	}
 
-	blkbuf = AllocatePool(blkbuf_size);
+	blkbuf = AllocatePool(alloc_size);
 	if (blkbuf == NULL) {
 		return EFI_OUT_OF_RESOURCES;
 	}
@@ -285,18 +286,16 @@ efi_block_find_partitions_disklabel(stru
     struct mbr_sector *mbr, uint32_t start, uint32_t size)
 {
 	struct efi_block_part *bpart;
-	char buf[DEV_BSIZE];
+	char buf[DEV_BSIZE]; /* XXX, arbitrary size >= struct disklabel */
 	struct disklabel d;
 	struct partition *p;
 	EFI_STATUS status;
 	int n;
 
 	status = efi_block_read(bdev,
-	    ((EFI_LBA)start + LABELSECTOR) * DEV_BSIZE, buf, sizeof(buf));
-	if (EFI_ERROR(status) || getdisklabel(buf, &d) != NULL) {
-		FreePool(buf);
+	    ((EFI_LBA)start + LABELSECTOR) * bdev->bio->Media->BlockSize, buf, sizeof(buf));
+	if (EFI_ERROR(status) || getdisklabel(buf, &d) != NULL)
 		return EIO;
-	}
 
 	if (le32toh(d.d_magic) != DISKMAGIC || le32toh(d.d_magic2) != DISKMAGIC)
 		return EINVAL;
@@ -419,7 +418,7 @@ efi_block_find_partitions_gpt(struct efi
 	void *buf;
 	UINTN sz;
 
-	status = efi_block_read(bdev, GPT_HDR_BLKNO * DEV_BSIZE, &hdr,
+	status = efi_block_read(bdev, (EFI_LBA)GPT_HDR_BLKNO * bdev->bio->Media->BlockSize, &hdr,
 	    sizeof(hdr));
 	if (EFI_ERROR(status)) {
 		return EIO;
@@ -436,7 +435,7 @@ efi_block_find_partitions_gpt(struct efi
 		return ENOMEM;
 
 	status = efi_block_read(bdev,
-	    le64toh(hdr.hdr_lba_table) * DEV_BSIZE, buf, sz);
+	    le64toh(hdr.hdr_lba_table) * bdev->bio->Media->BlockSize, buf, sz);
 	if (EFI_ERROR(status)) {
 		FreePool(buf);
 		return EIO;
@@ -682,6 +681,7 @@ int
 efi_block_strategy(void *devdata, int rw, daddr_t dblk, size_t size, void *buf, size_t *rsize)
 {
 	struct efi_block_part *bpart = devdata;
+	struct efi_block_dev *bdev = bpart->bdev;
 	EFI_STATUS status;
 	UINT64 off;
 
@@ -692,13 +692,13 @@ efi_block_strategy(void *devdata, int rw
 
 	switch (bpart->type) {
 	case EFI_BLOCK_PART_DISKLABEL:
-		off = (dblk + bpart->disklabel.part.p_offset) * DEV_BSIZE;
+		off = ((EFI_LBA)dblk + bpart->disklabel.part.p_offset) * bdev->bio->Media->BlockSize;
 		break;
 	case EFI_BLOCK_PART_GPT:
-		off = (dblk + le64toh(bpart->gpt.ent.ent_lba_start)) * DEV_BSIZE;
+		off = ((EFI_LBA)dblk + le64toh(bpart->gpt.ent.ent_lba_start)) * bdev->bio->Media->BlockSize;
 		break;
 	case EFI_BLOCK_PART_CD9660:
-		off = dblk * ISO_DEFAULT_BLOCK_SIZE;
+		off = (EFI_LBA)dblk * ISO_DEFAULT_BLOCK_SIZE;
 		break;
 	default:
 		return EINVAL;