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Re: [Qemu-block] [PATCH] qcow2: Assert that L2 table offsets fit in the
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-block] [PATCH] qcow2: Assert that L2 table offsets fit in the L1 table |
Date: |
Mon, 25 Feb 2019 15:05:44 +0100 |
User-agent: |
Mutt/1.11.3 (2019-02-01) |
Am 08.02.2019 um 16:44 hat Alberto Garcia geschrieben:
> L1 table entries have a field to store the offset of an L2 table.
> The rest of the bits of the entry are currently reserved except from
> bit 63, which stores the COPIED flag.
>
> The offset is always taken from the entry using L1E_OFFSET_MASK to
> ensure that we only use the bits that belong to that field.
>
> While that mask is used every time we read from the L1 table, it is
> never used when we write to it. Due to the limits set elsewhere in the
> code QEMU can never produce L2 table offsets that don't fit in that
> field so any such offset when allocating an L2 table would indicate a
> bug in QEMU.
>
> Signed-off-by: Alberto Garcia <address@hidden>
Thanks, applied to the block branch.
Kevin