[Qemu-devel] Question about IDE TRIM Command

[kazushi takahashi]

Hi all

I have a question about IDE TRIM Command.

As you know, QEMU have supported TRIM command since QEMU 0.15.0.

Some QEMU disk images such as qcow2 support bdrv_discard function
which will be called when guest OS executes ATA TRIM command.

So, I think qcow2 image has a function to delete the disk pages which are
recognized as discarded by guest OS.

I think that to enable TRIM Command, we have to emulate guest HDD as
Solid State Drive. However, it seems QEMU does not emulate guest
HDD as Solid State Drive. Thus, I think that bdrv_discard functions in
qemu images are never called by guest OS.

Is my thinking correct?

Thanks,
Kazushi Takahashi