[fixing Andre's email address] On 13/11/14 11:20, Christoffer Dall wrote: > On Thu, Nov 13, 2014 at 12:45:42PM +0200, Nikolay Nikolaev wrote: > > [...] > >>>> >>>> Going through the vgic_handle_mmio we see that it will require large >>>> refactoring: >>>> - there are 15 MMIO ranges for the vgic now - each should be >>>> registered as a separate device >>>> - the handler of each range should be split into read and write >>>> - all handlers take 'struct kvm_exit_mmio', and pass it to >>>> 'vgic_reg_access', 'mmio_data_read' and 'mmio_data_read' >>>> >>>> To sum up - if we do this refactoring of vgic's MMIO handling + >>>> kvm_io_bus_ API getting 'vcpu" argument we'll get a 'much' cleaner >>>> vgic code and as a bonus we'll get 'ioeventfd' capabilities. >>>> >>>> We have 3 questions: >>>> - is the kvm_io_bus_ getting 'vcpu' argument acceptable for the other >>>> architectures too? >>>> - is this huge vgic MMIO handling redesign acceptable/desired (it >>>> touches a lot of code)? >>>> - is there a way that ioeventfd is accepted leaving vgic.c in it's >>>> current state? >>>> >>> Not sure how the latter question is relevant to this, but check with >>> Andre who recently looked at this as well and decided that for GICv3 the >>> only sane thing was to remove that comment for the gic. >> @Andre - what's your experience with the GICv3 and MMIO handling, >> anything specific? >>> >>> I don't recall the details of what you were trying to accomplish here >>> (it's been 8 months or so) but the surely the vgic handling code should >>> *somehow* be integrated into the handle_kernel_mmio (like Paolo >>> suggested), unless you come back and tell me that that would involve a >>> complete rewrite of the vgic code. >> I'm experimenting now - it's not exactly rewrite of whole vgic code, >> but it will touch a lot of it - all MMIO access handlers and the >> supporting functions. >> We're ready to spend the effort. My question is - is this acceptable? >> > I certainly appreciate the offer to do this work, but it's hard to say > at this point if it is worth it. > > What I was trying to say above is that Andre looked at this, and came to > the conclusion that it is not worth it. > > Marc, what are your thoughts? Same here, I rely on Andre's view that it was not very useful. Now, it would be good to see a mock-up of the patches and find out: - if it is a major improvement for the general quality of the code - if that allow us to *delete* a lot of code (if it is just churn, I'm not really interested) - if it helps or hinders further developments that are currently in the pipeline Andre, can you please share your findings? I don't remember the specifics of the discussion we had a few months ago... Thanks, M. -- Jazz is not dead. It just smells funny... _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
