Problems using Block Io protocol in a CSM (worked in UDK2014.SP1, no longer works on master)

Problems using Block Io protocol in a CSM (worked in UDK2014.SP1, no longer works on master)

[Rebecca Cran]

I'm working to update a CSM (for bhyve) from UDK2014.SP1 to the latest 
master. I've already fixed several problems, but one I'm stuck on now is 
that while the code previously had no problem finding Block Io protocol 
via gBS->LocateHandleBuffer(ByProtocol, &gEfiBlockIoProtocolGuid, ...), 
it's no longer working: from looking through the debug log it appears 
the protocol is being torn down before our Legacy16PrepareToBoot 
function gets called.


I'm wondering if this was ever supposed to work and we just got lucky, 
or if something has changed in such a way that I just need to update/fix 
the code or add a dependency to make it work again?


-- 
Rebecca Cran

Re: [edk2-devel] Problems using Block Io protocol in a CSM (worked in UDK2014.SP1, no longer works on master)

[Laszlo Ersek]

On 05/09/20 04:59, Rebecca Cran wrote:
> I'm working to update a CSM (for bhyve) from UDK2014.SP1 to the latest
> master. I've already fixed several problems, but one I'm stuck on now is
> that while the code previously had no problem finding Block Io protocol
> via gBS->LocateHandleBuffer(ByProtocol, &gEfiBlockIoProtocolGuid, ...),
> it's no longer working: from looking through the debug log it appears
> the protocol is being torn down before our Legacy16PrepareToBoot
> function gets called.
> 
> 
> I'm wondering if this was ever supposed to work and we just got lucky,
> or if something has changed in such a way that I just need to update/fix
> the code or add a dependency to make it work again?
> 
> 

Is the protocol installed and then uninstalled, or is it never installed?

It is platform BDS policy what drivers are connected to what devices.
Perhaps the BlockIo protocol instance you're looking for is never
produced in the first place -- that could be explained by a platform BDS
change.

Thanks
Laszlo