On Mon, Jan 23, 2017 at 03:44:16PM +0000, Marc Zyngier wrote: > 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> > Thanks! I suppose looking at this again, I don't need the "irq_set_pending_latch()" indirection but I can just set this variable directly. What do you think? Would it be cleaner? -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
