On 23/01/17 13:39, Christoffer Dall wrote: > One of the goals behind the VGIC redesign was to get rid of cached or > intermediate state in the data structures, but we decided to allow > ourselves to precompute the pending value of an IRQ based on the line > level and pending latch state. However, this has now become difficult > to base proper GICv3 save/restore on, because there is a potential to > modify the pending state without knowing if an interrupt is edge or > level configured. > > See the following post and related message for more background: > https://lists.cs.columbia.edu/pipermail/kvmarm/2017-January/023195.html > > This commit gets rid of the precomputed pending field in favor of a > function that calculates the value when needed, irq_is_pending(). > > The soft_pending field is renamed to pending_latch to represent that > this latch is the equivalent hardware latch which gets manipulated by > the input signal for edge-triggered interrupts and when writing to the > SPENDR/CPENDR registers. > > After this commit save/restore code should be able to simply restore the > pending_latch state, line_level state, and config state in any order and > get the desired result. > > Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx> I admit having lost a few brain cells looking at this patch, and I can't prove it wrong! ;-) I like the fact that it now provides a safe abstraction to the pending state, and that there is exactly *one* place where line_level is evaluated. Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx> M. -- Jazz is not dead. It just smells funny... _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
