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Re: [Qemu-devel] [PATCH] ide: refuse WIN_READ_NATIVE_MAX on empty device
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] [PATCH] ide: refuse WIN_READ_NATIVE_MAX on empty device |
Date: |
Fri, 05 Apr 2013 12:56:07 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) |
Stefan Hajnoczi <address@hidden> writes:
> What is the highest addressable sector on an empty CD-ROM? Nothing is
> addressable so produce an error.
>
> This patch prevents a divide-by-zero in ide_set_sector() since
> s->sectors and s->heads would be 0. Not to mention that a sector=-1
> argument would be nonsense.
>
> Note that WIN_READ_NATIVE_MAX can be triggered using hdparm -N 1024
> /dev/cdrom. The LBA bit will be set to 1 though, so the only easy way
> to go down the ide_set_sector() CHS code path which divides by zero is
> to comment out the s->select & 0x40 case for testing.
Suggests you did that.
Have you tried the reproducer with a physical drive? Does it fail the
command when empty, too?
Re: [Qemu-devel] [PATCH] ide: refuse WIN_READ_NATIVE_MAX on empty device, Stefan Hajnoczi, 2013/04/10