Re: EFI shell with microvm

["Boeuf, Sebastien" <sebastien.boeuf@intel.com>]

On Thu, 2022-01-06 at 13:44 +0100, kraxel@redhat.com wrote:
> On Thu, Jan 06, 2022 at 11:25:37AM +0000, Boeuf, Sebastien wrote:
> > Hi Gerd,
> > 
> > I was looking at a way to add support for EFI shell interaction
> > with Cloud Hypervisor when
> > I realized you added the support for microvm with commit
> > 55f47d22998.
> > I have been able to hack OvmfPkgX64 similarly to get it to work,
> > but here are two follow up
> > questions:
> 
> How do you want interact?  Serial console?  That should work just
> fine
> with OvmfPkgX64.

Yes I'd like to use the serial console (available on PIO 0x3f8) to
interact with the EFI shell.

> 
> qemu-system-x86_64 -nographic -bios
> Build/OvmfX64/DEBUG_GCC5/FV/OVMF.fd -net none
> 
> Possibly you have to add the cloud hypervisor pci id somewhere so isa
> lpc and serial line driver are initialized properly.  SioBusDxe looks
> like a hot candidate.
> 
> microvm has no lpc bridge, so I had to do it in a different way ...

Cloud Hypervisor doesn't emulate any LPC bridge or ISA bus.

> 
> > 2. I can see the shell but I can't interact with it, do you have a
> > similar behavior with microvm
> > or is it because I'm missing the interrupt support?
> 
> Works fine for me.
> 
> qemu-system-x86_64 -nographic -machine microvm,rtc=on -bios
> Build/MicrovmX64/DEBUG_GCC5/FV/MICROVM.fd

Thanks for the confirmation, something might be wrong with the
interrupt used for my serial device.
Cloud Hypervisor only has an IOAPIC, it doesn't rely on any PIC, which
is why I'm not sure what might be missing to get the EFI shell to
receive the interrupts.

> 
> HTH,
>   Gerd
> 

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