Re: [PATCH v2 1/4] usb: early: Avoid using DbC if already enabled

From: Jan Beulich
Date: Mon May 17 2021 - 10:16:44 EST


On 17.05.2021 15:48, Connor Davis wrote:
>
> On 5/17/21 3:32 AM, Jan Beulich wrote:
>> On 14.05.2021 02:56, Connor Davis wrote:
>>> Check if the debug capability is enabled in early_xdbc_parse_parameter,
>>> and if it is, return with an error. This avoids collisions with whatever
>>> enabled the DbC prior to linux starting.
>> Doesn't this go too far and prevent use even if firmware (perhaps
>> mistakenly) left it enabled?
>
> Yes, but how is one supposed to distinguish the broken firmware and
> non-broken
>
> firmware cases?

Well, a first step might be to only check if running virtualized.
And then if your running virtualized, there might be a way to
inquire the hypervisor?

Jan