kvm: x86: Extended struct kvm_lapic_irq with msi_redir_hint for MSI delivery

Extended struct kvm_lapic_irq with bool msi_redir_hint, which will
be used to determine if the delivery of the MSI should target only
the lowest priority CPU in the logical group specified for delivery.
(In physical dest mode, the RH bit is not relevant). Initialized the value
of msi_redir_hint to true when RH=1 in kvm_set_msi_irq(), and initialized
to false in all other cases.

Added value of msi_redir_hint to a debug message dump of an IRQ in
apic_send_ipi().
Signed-off-by: James Sullivan <sullivan.james.f@gmail.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -695,6 +695,7 @@ struct kvm_lapic_irq {
 	u16 trig_mode;
 	u32 shorthand;
 	u32 dest_id;
+	bool msi_redir_hint;
 };
 
 struct kvm_x86_ops {

arch/x86/kvm/ioapic.c

@@ -349,6 +349,7 @@ static int ioapic_service(struct kvm_ioapic *ioapic, int irq, bool line_status)
 	irqe.delivery_mode = entry->fields.delivery_mode << 8;
 	irqe.level = 1;
 	irqe.shorthand = 0;
+	irqe.msi_redir_hint = false;
 
 	if (irqe.trig_mode == IOAPIC_EDGE_TRIG)
 		ioapic->irr_delivered |= 1 << irq;

arch/x86/kvm/irq_comm.c

@@ -106,9 +106,10 @@ static inline void kvm_set_msi_irq(struct kvm_kernel_irq_routing_entry *e,
 	irq->dest_mode = (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo;
 	irq->trig_mode = (1 << MSI_DATA_TRIGGER_SHIFT) & e->msi.data;
 	irq->delivery_mode = e->msi.data & 0x700;
+	irq->msi_redir_hint = ((e->msi.address_lo
+		& MSI_ADDR_REDIRECTION_LOWPRI) > 0);
 	irq->level = 1;
 	irq->shorthand = 0;
-	/* TODO Deal with RH bit of MSI message address */
 }
 
 int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,

arch/x86/kvm/lapic.c

@@ -917,6 +917,7 @@ static void apic_send_ipi(struct kvm_lapic *apic)
 	irq.level = (icr_low & APIC_INT_ASSERT) != 0;
 	irq.trig_mode = icr_low & APIC_INT_LEVELTRIG;
 	irq.shorthand = icr_low & APIC_SHORT_MASK;
+	irq.msi_redir_hint = false;
 	if (apic_x2apic_mode(apic))
 		irq.dest_id = icr_high;
 	else
@@ -926,10 +927,11 @@ static void apic_send_ipi(struct kvm_lapic *apic)
 
 	apic_debug("icr_high 0x%x, icr_low 0x%x, "
 		   "short_hand 0x%x, dest 0x%x, trig_mode 0x%x, level 0x%x, "
-		   "dest_mode 0x%x, delivery_mode 0x%x, vector 0x%x\n",
+		   "dest_mode 0x%x, delivery_mode 0x%x, vector 0x%x, "
+		   "msi_redir_hint 0x%x\n",
 		   icr_high, icr_low, irq.shorthand, irq.dest_id,
 		   irq.trig_mode, irq.level, irq.dest_mode, irq.delivery_mode,
-		   irq.vector);
+		   irq.vector, irq.msi_redir_hint);
 
 	kvm_irq_delivery_to_apic(apic->vcpu->kvm, apic, &irq, NULL);
 }

arch/x86/kvm/x86.c

@@ -5984,6 +5984,7 @@ static void kvm_pv_kick_cpu_op(struct kvm *kvm, unsigned long flags, int apicid)
 	lapic_irq.shorthand = 0;
 	lapic_irq.dest_mode = 0;
 	lapic_irq.dest_id = apicid;
+	lapic_irq.msi_redir_hint = false;
 
 	lapic_irq.delivery_mode = APIC_DM_REMRD;
 	kvm_irq_delivery_to_apic(kvm, NULL, &lapic_irq, NULL);