Enabling interrupts in QEMU TPM TIS

[Jason Gunthorpe]

On Thu, Jun 25, 2020 at 10:56:43AM -0400, Stefan Berger wrote:
> Hello!
> 
>  I want to enable IRQs now in QEMU's TPM TIS device model and I need to work
> with the following patch to Linux TIS. I am wondering whether the changes
> there look reasonable to you? Windows works with the QEMU modifications
> as-is, so maybe it's a bug in the TIS code (which I had not run into
> before).
> 
> 
> The point of the loop I need to introduce in the interrupt handler is that
> while the interrupt handler is running another interrupt may occur/be posted
> that then does NOT cause the interrupt handler to be invoked again but
> causes a stall, unless the loop is there.

That seems like a qemu bug, TPM interrupts are supposed to be level
interrupts, not edge.

Jason