[libvirt] [PATCH] qemu: Put format=raw onto cmd line for SCSI passthrough

[Michal Privoznik]

On 10/12/2018 02:17 PM, Daniel P. Berrangé wrote:
> On Fri, Oct 12, 2018 at 01:14:51PM +0200, Michal Privoznik wrote:
>> https://bugzilla.redhat.com/show_bug.cgi?id=1632833
>>
>> When doing a SCSI passthrough we don't put format= onto the
>> command line. This causes qemu to probe the format automatically
>> which ends up in a warning in the domain log and possible qemu
>> disabling writes to the first block (according to the warning
>> message).
> 
> If the warning message is correct, this should have been reported
> as a security bug to libvirt and given a CVE.

Why is that? It the message is correct, qemu would prevent from writing
to the first block. No harm there.

> 
> On the other hand if the warning from QEMU isn't correct, then
> QEMU shouldn't have printed the warning about it being dangerous.

In my testing I was able to write to the first block. Therefore, IMO
qemu is throwing incorrect warning message.

> 
> So something is missing here either way.

Sure, but that doesn't invalidate my patch, does it?

Michal