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| author | Paolo Bonzini <pbonzini@redhat.com> | 2012-09-05 17:54:36 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2012-09-21 16:12:34 +0200 |
| commit | 12ca76fc48081b3a0ad1a70546abfcf198aedfc4 (patch) | |
| tree | e90b1b5b27372f04d1f315b3fc3d62ba45a17a5f /hw/scsi-disk.c | |
| parent | 444bc908611ccaf4512dc37c33ac3b54d873a62b (diff) | |
scsi-disk: fix check for out-of-range LBA
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 <pbonzini@redhat.com>
Diffstat (limited to 'hw/scsi-disk.c')
| -rw-r--r-- | hw/scsi-disk.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c index 3959603b0f..d621852857 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 { |