[RFC PATCH v1] powerpc/prom_init: disable XIVE in Secure VM.

[Cédric Le Goater]

On 3/5/20 12:55 AM, David Gibson wrote:
> On Wed, Mar 04, 2020 at 04:56:09PM +0100, Cédric Le Goater wrote:
>> [ ... ]
>>
>>> (1) applied the patch which shares the EQ-page with the hypervisor.
>>> (2) set "kernel_irqchip=off"
>>> (3) set "ic-mode=xive"
>>
>> you don't have to set the interrupt mode. xive should be negotiated
>> by default.
>>
>>> (4) set "svm=on" on the kernel command line.
>>> (5) no changes to the hypervisor and ultravisor.
>>>
>>> And Boom it works!.   So you were right.
>>
>> Excellent.
>>  
>>> I am sending out the patch for (1) above ASAP.
>>
>> Next step, could you please try to do the same with the TIMA and ESB pfn ?
>> and use KVM.
> 
> I'm a bit confused by this.  Aren't the TIMA and ESB pages essentially
> IO pages, rather than memory pages from the guest's point of view?

yes. 

> I assume only memory pages are protected with PEF - I can't even really
> see what protecting an IO page would even mean.

AFAIUI, the ultravisor needs to be aware of these IO page frames. We have 
the information in KVM but we need to inform the ultravisor in some ways.
It could be done earlier than in the page fault handler.

C.