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[Qemu-devel] [PATCH 4/7] scsi-disk: fix check for out-of-range LBA
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 4/7] scsi-disk: fix check for out-of-range LBA |
Date: |
Fri, 21 Sep 2012 16:52:46 +0200 |
This fix is needed to correctly handle 0-block read and writes.
Without it, a 0-block access at LBA 0 would underflow.
Signed-off-by: Paolo Bonzini <address@hidden>
---
hw/scsi-disk.c | 6 +++++-
1 file modificato, 5 inserzioni(+). 1 rimozione(-)
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 3959603..d621852 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -1456,9 +1456,13 @@ static inline bool check_lba_range(SCSIDiskState *s,
* The first line tests that no overflow happens when computing the last
* sector. The second line tests that the last accessed sector is in
* range.
+ *
+ * Careful, the computations should not underflow for nb_sectors == 0,
+ * and a 0-block read to the first LBA beyond the end of device is
+ * valid.
*/
return (sector_num <= sector_num + nb_sectors &&
- sector_num + nb_sectors - 1 <= s->qdev.max_lba);
+ sector_num + nb_sectors <= s->qdev.max_lba + 1);
}
typedef struct UnmapCBData {
--
1.7.12
- [Qemu-devel] [PULL 0/7] SCSI patches for 2012-09-21, Paolo Bonzini, 2012/09/21
- [Qemu-devel] [PATCH 2/7] iSCSI: We dont need to explicitely call qemu_notify_event() any more, Paolo Bonzini, 2012/09/21
- [Qemu-devel] [PATCH 3/7] scsi-disk: introduce check_lba_range, Paolo Bonzini, 2012/09/21
- [Qemu-devel] [PATCH 4/7] scsi-disk: fix check for out-of-range LBA,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 1/7] iSCSI: We need to support SG_IO also from iscsi_ioctl(), Paolo Bonzini, 2012/09/21
- [Qemu-devel] [PATCH 6/7] scsi-disk: use scsi_data_cdb_length, Paolo Bonzini, 2012/09/21
- [Qemu-devel] [PATCH 5/7] scsi: introduce scsi_cdb_length and scsi_data_cdb_length, Paolo Bonzini, 2012/09/21
- [Qemu-devel] [PATCH 7/7] SCSI: Standard INQUIRY data should report HiSup flag as set., Paolo Bonzini, 2012/09/21
- Re: [Qemu-devel] [PULL 0/7] SCSI patches for 2012-09-21, Anthony Liguori, 2012/09/25