> -----Original Message----- > From: Will Deacon [mailto:will@xxxxxxxxxx] > Sent: 03 August 2021 12:39 > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; kvmarm@xxxxxxxxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; maz@xxxxxxxxxx; catalin.marinas@xxxxxxx; > james.morse@xxxxxxx; julien.thierry.kdev@xxxxxxxxx; > suzuki.poulose@xxxxxxx; jean-philippe@xxxxxxxxxx; > Alexandru.Elisei@xxxxxxx; qperret@xxxxxxxxxx; Linuxarm > <linuxarm@xxxxxxxxxx> > Subject: Re: [PATCH v3 1/4] KVM: arm64: Introduce a new VMID allocator for > KVM > > On Thu, Jul 29, 2021 at 11:40:06AM +0100, Shameer Kolothum wrote: > > A new VMID allocator for arm64 KVM use. This is based on > > arm64 ASID allocator algorithm. > > > > One major deviation from the ASID allocator is the way we > > flush the context. Unlike ASID allocator, we expect less > > frequent rollover in the case of VMIDs. Hence, instead of > > marking the CPU as flush_pending and issuing a local context > > invalidation on the next context switch, we broadcast TLB > > flush + I-cache invalidation over the inner shareable domain > > on rollover. > > > > Signed-off-by: Shameer Kolothum > <shameerali.kolothum.thodi@xxxxxxxxxx> > > --- > > [...] > > > +void kvm_arm_vmid_update(struct kvm_vmid *kvm_vmid) > > +{ > > + unsigned long flags; > > + unsigned int cpu; > > + u64 vmid, old_active_vmid; > > + > > + vmid = atomic64_read(&kvm_vmid->id); > > + > > + /* > > + * Please refer comments in check_and_switch_context() in > > + * arch/arm64/mm/context.c. > > + */ > > + old_active_vmid = atomic64_read(this_cpu_ptr(&active_vmids)); > > + if (old_active_vmid && vmid_gen_match(vmid) && > > + atomic64_cmpxchg_relaxed(this_cpu_ptr(&active_vmids), > > + old_active_vmid, vmid)) > > + return; > > + > > + raw_spin_lock_irqsave(&cpu_vmid_lock, flags); > > + > > + /* Check that our VMID belongs to the current generation. */ > > + vmid = atomic64_read(&kvm_vmid->id); > > + if (!vmid_gen_match(vmid)) { > > + vmid = new_vmid(kvm_vmid); > > + atomic64_set(&kvm_vmid->id, vmid); > > new_vmid() can just set kvm_vmid->id directly Ok. > > > + } > > + > > + cpu = smp_processor_id(); > > Why? Left over from previous one. Forgot to remove as we don't have the tlb_flush_pending check anymore. Thanks, Shameer > > Will _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
