Hi Christoffer, On 22/03/17 13:37, Christoffer Dall wrote: > Hi Marc, > > > On Tue, Mar 21, 2017 at 07:20:30PM +0000, Marc Zyngier wrote: >> As noticed by RMK in this thread[1], the hyp-stub API on 32bit ARM >> could do with some TLC (it cannot perform a soft-restart at HYP, and >> has holes in the hyp-stub support in a number of places). In general, >> it would be desirable for the 32bit behaviour to align on 64bit, if >> only to ease maintenance. >> >> This series implements the following: >> - Add HVC_[GS]ET_VECTORS and HVC_SOFT_RESTART to the 32bit code >> - Add HVC_RESET_VECTORS to both arm and arm64, removing the need for >> __hyp_reset_vectors >> - Implement add the stub entry points in the KVM init code, which >> didn't implement any so far >> - Convert the HYP code to use the init code stubs directly >> - Some general cleanup as a result of these changes (which includes >> killing HVC_GET_VECTORS) >> - Add some API documentation that covers the above >> >> Patches 12 to 14 would be better squashed into 10 and 11, but I've >> kept them separate so that I can take the blame for everything I've >> broken. > > This series looks great overall. I'm still going through the details of > the patches, but one high level questions: > > What if we formalized the way to call a function in Hyp mode, whatever > its current configuration may be, via a specific HVC number. That would > mean that the documentation say nothing of a hypervisor specific > implementaiton. Do you mean an actual function call indirected via an HVC? Similar to what we already do today for KVM when we want to call HYP functions? > Could we then use that to initialize hyp mode for a hypervisor, i.e. > KVM, without having to actually change the vectors? Couldn't we simply > use the the hvc stub to call a function in the physical address space, > and be rid of the concept of hyp-init alltogether? My problem here is when you say "in the physical space". Do you want to be able to call such a function from any context? That's certainly doable now, but I'm not completely sure of what we get. Maybe I just don't see the use case - can you enlighten me? Thanks, M. -- Jazz is not dead. It just smells funny...
