Re: [PATCH] hw/nvme: Add options to override hardcoded values

[Keith Busch]

On Sun, Jun 12, 2022 at 12:35:09AM +0200, Mauricio Sandt wrote:
> This small patch is the result of some recent malware research I did
> in a QEMU VM. The malware used multiple ways of querying info from
> the VM disk and I needed a clean way to change those values from the
> hypervisor.
> 
> I believe this functionality could be useful to more people from multiple
> fields, sometimes you just want to change some default values and having
> them hardcoded in the sourcecode makes that much harder.
> 
> This patch adds three config parameters to the nvme device, all of them
> are optional to not break anything. If any of them are not specified,
> the previous (before this patch) default is used.
> 
> -model - This takes a string and sets it as the devices model name.
> If you don't specify this parameter, the default is "QEMU NVMe Ctrl".
> 
> -firmware - The firmware version string, max 8 ascii characters.
> The default is whatever `QEMU_VERSION` evaluates to.
> 
> -nqn_override - Allows to set a custom nqn on the nvme device.
> Only used if there is no subsystem. This string should be in the same
> format as the default "nqn.2019-08.org.qemu:...", but there is no
> validation for that. Its up to the user to provide a valid string.

I guess the nqn can be user tunable just like it is when used with subsystems,
but what's the point of messing with model and firmware? That could mess with
host drivers' ability to detect what quirks it needs to apply to specific
instances of this virtual controller.