On Tue, Dec 05, 2017 at 10:09:15AM +0100, Christoffer Dall wrote: > On Fri, Dec 01, 2017 at 03:19:40PM +0000, Dave Martin wrote: > > The HCR_EL2.TID3 flag needs to be set when trapping guest access to > > the CPU ID registers is required. However, the decision about > > whether to set this bit does not need to be repeated at every > > switch to the guest. > > > > Instead, it's sufficient to make this decision once and record the > > outcome. > > > > This patch moves the decision to vcpu_reset_hcr() and records the > > choice made in vcpu->arch.hcr_el2. The world switch code can then > > load this directly when switching to the guest without the need for > > conditional logic on the critical path. > > > > Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx> > > Suggested-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx> > > Cc: Marc Zyngier <marc.zyngier@xxxxxxx> > > Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx> > > > > > --- > > > > Note to maintainers: this was discussed on-list [1] prior to the merge > > window, but this patch implementing the agreed decision hasn't been > > posted previously. > > > > This should be considered a fix for v4.15. > > It's actually easier for me to apply this for v4.16 and base my VHE > optimization patches on it. If you're happy for this optimisation to be missing for v4.15, I'm fine with that. Can I leave it you to pick this up then? I'll repost the other stuff from this series separately for Will to take care of. Cheers ---Dave _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
