Re: [PATCH v3 3/4] KVM: x86: Add EOI exit bitmap inference

[Steve Rutherford <srutherford@google.com>]

On Wed, Jun 03, 2015 at 11:16:16AM +0200, Paolo Bonzini wrote:
> 
> 
> On 03/06/2015 01:51, Steve Rutherford wrote:
> > +static inline void kvm_arch_irq_routing_update(struct kvm *kvm)
> > +{
> > +}
> 
> Please add the static inline to all arches instead of putting it in
> #ifndef __KVM_HAVE_IOAPIC.  It's not related to the existence of an ioapic.
> 
> > 
> > +void kvm_arch_irq_routing_update(struct kvm *kvm)
> > +{
> > +	struct kvm_ioapic *ioapic = kvm->arch.vioapic;
> > +
> > +	if (ioapic)
> > +		return;
> > +	if (!lapic_in_kernel(kvm))
> > +		return;
> > +	kvm_make_scan_ioapic_request(kvm);
> > +}
> > +
> 
> It's weird to have a function in ioapic.c that only does something if
> you _do not_ have an ioapic. :)
> 
> > +
> > +void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
> 
> This must stay in arch/x86/kvm/.  I'd put both of these in irq_comm.c.
> 
> Then you do not need kvm_arch_nr_userspace_ioapic_pins anymore.
Yes! This is way cleaner. I'll make these changes.

Steve
> 
> Paolo
> 
> > +{
> > +	struct kvm *kvm = vcpu->kvm;
> > +	struct kvm_kernel_irq_routing_entry *entry;
> > +	struct kvm_irq_routing_table *table;
> > +	u32 i, nr_ioapic_pins;
> > +	int idx;
> > +
> > +	/* kvm->irq_routing must be read after clearing
> > +	 * KVM_SCAN_IOAPIC. */
> > +	smp_mb();
> > +	idx = srcu_read_lock(&kvm->irq_srcu);
> > +	table = kvm->irq_routing;
> > +	nr_ioapic_pins = min_t(u32, table->nr_rt_entries,
> > +			      kvm_arch_nr_userspace_ioapic_pins(kvm));
> > +	for (i = 0; i < nr_ioapic_pins; ++i) {
> > +		hlist_for_each_entry(entry, &table->map[i], link) {
> > +			u32 dest_id, dest_mode;
> > +
> > +			if (entry->type != KVM_IRQ_ROUTING_MSI)
> > +				continue;
> > +			dest_id = (entry->msi.address_lo >> 12) & 0xff;
> > +			dest_mode = (entry->msi.address_lo >> 2) & 0x1;
> > +			if (kvm_apic_match_dest(vcpu, NULL, 0, dest_id,
> > +						dest_mode)) {
> > +				u32 vector = entry->msi.data & 0xff;
> > +
> > +				__set_bit(vector,
> > +					  (unsigned long *) eoi_exit_bitmap);
> > +			}
> > +		}
> > +	}
> > +	srcu_read_unlock(&kvm->irq_srcu, idx);
> > +}