Re: [PATCH] s390x: Properly fetch and test the short psw on diag308 subc 0/1

[Janosch Frank <frankja@linux.ibm.com>]

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On 11/5/19 9:07 PM, David Hildenbrand wrote:
> On 05.11.19 20:34, Janosch Frank wrote:
>> On 11/5/19 8:29 PM, David Hildenbrand wrote:
>>> On 05.11.19 19:44, Janosch Frank wrote:
[...]
> Note: For TCG we miss many of these validity checks. For KVM, most 
> should be triggered when running the VCPU AFAIK (that means, we don't 
> have to check for any other scenarios here). Checking for the special 
> case as given in the programming note should be sufficient.
> 
> 
> I'll have to think about how to best handle that for TCG (mazbe what I 
> proposed works). We could ignore TCG for now and add a TODO. Then, just 
> wrap the exception in a "if (kvm_enabled())". You could also document 
> why we only have to check for this very specific bit and not the other 
> bits (handled by HW later).
> 

After some discussion I got an interesting answer:
For KVM we need to expand the short psw and invert bit 12.
The next SIE entry will automatically report a PIC 6.

I'd propose that I'll fix this patch and send a v2 and you can fix TCG :)


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