[PATCH 5/9] KVM: support x2APIC ID in userspace routes

["Radim Krčmář" <rkrcmar@redhat.com>]

We need a way to pass 32 bit APIC ID.  Intel® Virtualization Technology
for Directed I/O, 5.1.8 Programming in Intel® 64 x2APIC Mode, specifies
that Remapping Hardware is configured with APIC ID 31:8 in Upper Address
Register 31:8.  This patch adopts that method and applies it to
KVM_SIGNAL_MSI and GSI routes.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 Documentation/virtual/kvm/api.txt | 11 ++++++++++-
 arch/x86/kvm/irq_comm.c           |  9 +++++++--
 arch/x86/kvm/vmx.c                |  3 ++-
 arch/x86/kvm/x86.c                |  1 +
 include/uapi/linux/kvm.h          |  5 +++++
 virt/kvm/irqchip.c                |  6 +++++-
 6 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 4d0542c5206b..07bcedc0ba09 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1461,6 +1461,7 @@ struct kvm_irq_routing_entry {
 #define KVM_IRQ_ROUTING_MSI 2
 #define KVM_IRQ_ROUTING_S390_ADAPTER 3
 #define KVM_IRQ_ROUTING_HV_SINT 4
+#define KVM_IRQ_ROUTING_MSI_X2APIC 5
 
 No flags are specified so far, the corresponding field must be set to zero.
 
@@ -1489,6 +1490,11 @@ struct kvm_irq_routing_hv_sint {
 	__u32 sint;
 };
 
+KVM_IRQ_ROUTING_MSI_X2APIC can be used if KVM_CAP_MSI_X2APIC is present.
+The entry uses struct kvm_irq_routing_msi and stores APIC ID bits 8-31 in
+address_hi bits 8-31.
+
+
 4.53 KVM_ASSIGN_SET_MSIX_NR (deprecated)
 
 Capability: none
@@ -2166,7 +2172,10 @@ struct kvm_msi {
 	__u8  pad[16];
 };
 
-No flags are defined so far. The corresponding field must be 0.
+Valid flags are 0 and bitwise OR of any following:
+* KVM_SIGNAL_MSI_X2APIC
+  - valid with capability KVM_CAP_MSI_X2APIC
+  - address_hi bits 8-31 contain APIC ID bits 8-31
 
 
 4.71 KVM_CREATE_PIT2
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index 3d17eee0987b..b9595251834b 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -117,6 +117,8 @@ void kvm_set_msi_irq(struct kvm_kernel_irq_routing_entry *e,
 
 	irq->dest_id = (e->msi.address_lo &
 			MSI_ADDR_DEST_ID_MASK) >> MSI_ADDR_DEST_ID_SHIFT;
+	if (e->type == KVM_IRQ_ROUTING_MSI_X2APIC)
+		irq->dest_id |= MSI_ADDR_EXT_DEST_ID(e->msi.address_hi);
 	irq->vector = (e->msi.data &
 			MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT;
 	irq->dest_mode = (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo;
@@ -150,7 +152,8 @@ int kvm_arch_set_irq_inatomic(struct kvm_kernel_irq_routing_entry *e,
 	struct kvm_lapic_irq irq;
 	int r;
 
-	if (unlikely(e->type != KVM_IRQ_ROUTING_MSI))
+	if (unlikely(e->type != KVM_IRQ_ROUTING_MSI &&
+	             e->type != KVM_IRQ_ROUTING_MSI_X2APIC))
 		return -EWOULDBLOCK;
 
 	kvm_set_msi_irq(e, &irq);
@@ -281,6 +284,7 @@ int kvm_set_routing_entry(struct kvm_kernel_irq_routing_entry *e,
 			goto out;
 		break;
 	case KVM_IRQ_ROUTING_MSI:
+	case KVM_IRQ_ROUTING_MSI_X2APIC:
 		e->set = kvm_set_msi;
 		e->msi.address_lo = ue->u.msi.address_lo;
 		e->msi.address_hi = ue->u.msi.address_hi;
@@ -393,7 +397,8 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu,
 		hlist_for_each_entry(entry, &table->map[i], link) {
 			struct kvm_lapic_irq irq;
 
-			if (entry->type != KVM_IRQ_ROUTING_MSI)
+			if (entry->type != KVM_IRQ_ROUTING_MSI &&
+			    entry->type != KVM_IRQ_ROUTING_MSI_X2APIC)
 				continue;
 
 			kvm_set_msi_irq(entry, &irq);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 133679d520af..35df8d757d1d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10829,7 +10829,8 @@ static int vmx_update_pi_irte(struct kvm *kvm, unsigned int host_irq,
 	BUG_ON(guest_irq >= irq_rt->nr_rt_entries);
 
 	hlist_for_each_entry(e, &irq_rt->map[guest_irq], link) {
-		if (e->type != KVM_IRQ_ROUTING_MSI)
+		if (e->type != KVM_IRQ_ROUTING_MSI &&
+		    e->type != KVM_IRQ_ROUTING_MSI_X2APIC)
 			continue;
 		/*
 		 * VT-d PI cannot support posting multicast/broadcast
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9b7798c7b210..86d1eb1c9d8b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2567,6 +2567,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_DISABLE_QUIRKS:
 	case KVM_CAP_SET_BOOT_CPU_ID:
  	case KVM_CAP_SPLIT_IRQCHIP:
+	case KVM_CAP_MSI_X2APIC:
 #ifdef CONFIG_KVM_DEVICE_ASSIGNMENT
 	case KVM_CAP_ASSIGN_DEV_IRQ:
 	case KVM_CAP_PCI_2_3:
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index a7f1f8032ec1..af1abec5f41d 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -865,6 +865,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_SPAPR_TCE_64 125
 #define KVM_CAP_ARM_PMU_V3 126
 #define KVM_CAP_VCPU_ATTRIBUTES 127
+#define KVM_CAP_MSI_X2APIC 128
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -898,6 +899,7 @@ struct kvm_irq_routing_hv_sint {
 #define KVM_IRQ_ROUTING_MSI 2
 #define KVM_IRQ_ROUTING_S390_ADAPTER 3
 #define KVM_IRQ_ROUTING_HV_SINT 4
+#define KVM_IRQ_ROUTING_MSI_X2APIC 5 /* KVM_CAP_MSI_X2APIC */
 
 struct kvm_irq_routing_entry {
 	__u32 gsi;
@@ -1023,6 +1025,9 @@ struct kvm_one_reg {
 	__u64 addr;
 };
 
+#define KVM_SIGNAL_MSI_X2APIC  (1 <<  0) /* KVM_CAP_X2APIC */
+#define KVM_SIGNAL_MSI_FLAGS   KVM_SIGNAL_MSI_X2APIC
+
 struct kvm_msi {
 	__u32 address_lo;
 	__u32 address_hi;
diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
index fe84e1a95dd5..39b38b1a2156 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -62,9 +62,13 @@ int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
 {
 	struct kvm_kernel_irq_routing_entry route;
 
-	if (!irqchip_in_kernel(kvm) || msi->flags != 0)
+	if (!irqchip_in_kernel(kvm) ||
+	    (msi->flags & ~KVM_SIGNAL_MSI_FLAGS) != 0)
 		return -EINVAL;
 
+	/* assignment must copy kvm_set_routing_entry() */
+	route.type = msi->flags & KVM_SIGNAL_MSI_X2APIC ?
+		KVM_IRQ_ROUTING_MSI_X2APIC : KVM_IRQ_ROUTING_MSI;
 	route.msi.address_lo = msi->address_lo;
 	route.msi.address_hi = msi->address_hi;
 	route.msi.data = msi->data;
-- 
2.8.2