git: 7e04dc0797f3 - stable/13 - stand: i386: take into account disk sector size for blk calculation

From: Kyle Evans <kevans_at_FreeBSD.org>
Date: Sun, 18 Sep 2022 06:27:10 UTC
The branch stable/13 has been updated by kevans:

URL: https://cgit.FreeBSD.org/src/commit/?id=7e04dc0797f3265a10975cac2670f0407487a925

commit 7e04dc0797f3265a10975cac2670f0407487a925
Author:     Kyle Evans <kevans@FreeBSD.org>
AuthorDate: 2022-09-08 00:35:06 +0000
Commit:     Kyle Evans <kevans@FreeBSD.org>
CommitDate: 2022-09-18 06:26:40 +0000

    stand: i386: take into account disk sector size for blk calculation
    
    disk_blocks assumes BIOSDISK_SECSIZE, but the media may not be using
    it.  In particular, bioscd on Parallels presents a 2K sector size, so
    we end up with a short disk_blocks and subsequent validation fails when
    trying to read /boot/lua.
    
    PR:             233098
    Reviewed by:    imp, tsoome
    
    (cherry picked from commit 72291cee075d9ef1a608b2a67762b44e024cc0d4)
---
 stand/i386/libi386/biosdisk.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/stand/i386/libi386/biosdisk.c b/stand/i386/libi386/biosdisk.c
index 2c52617f255d..f8c712b324c6 100644
--- a/stand/i386/libi386/biosdisk.c
+++ b/stand/i386/libi386/biosdisk.c
@@ -1031,7 +1031,8 @@ bd_realstrategy(void *devdata, int rw, daddr_t dblk, size_t size,
 		d_offset = dev->d_offset;
 	}
 	if (disk_blocks == 0)
-		disk_blocks = bd->bd_sectors - d_offset;
+		disk_blocks = bd->bd_sectors * (bd->bd_sectorsize /
+		    BIOSDISK_SECSIZE) - d_offset;
 
 	/* Validate source block address. */
 	if (dblk < d_offset || dblk >= d_offset + disk_blocks)