From: Kevin Wolf <kwolf@redhat.com>
To: Alberto Garcia <berto@igalia.com>
Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org,
Max Reitz <mreitz@redhat.com>, Eric Blake <eblake@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v2] qcow2: Assert that refcount block offsets fit in the refcount table
Date: Tue, 8 Jan 2019 16:53:55 +0100 [thread overview]
Message-ID: <20190108155355.GH11492@linux.fritz.box> (raw)
In-Reply-To: <20181114145857.19720-1-berto@igalia.com>
Am 14.11.2018 um 15:58 hat Alberto Garcia geschrieben:
> Refcount table entries have a field to store the offset of the
> refcount block. The rest of the bits of the entry are currently
> reserved.
>
> The offset is always taken from the entry using REFT_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 refcount table, it
> is never used when we write to it. Due to the other constraints of the
> qcow2 format QEMU can never produce refcount block offsets that don't
> fit in that field so any such offset when allocating a refcount block
> would indicate a bug in QEMU.
>
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
Thanks, applied to the block branch.
Kevin
prev parent reply other threads:[~2019-01-08 15:54 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-14 14:58 [Qemu-devel] [PATCH v2] qcow2: Assert that refcount block offsets fit in the refcount table Alberto Garcia
2018-12-14 9:52 ` Alberto Garcia
2019-01-08 15:37 ` Alberto Garcia
2019-01-08 15:53 ` Kevin Wolf [this message]
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