[PATCH 14/14] extend GSI IRQ routing to take a device ID

[Andre Przywara]

For ITS emulation we need the device ID along with the MSI payload
and doorbell address to identify an MSI, so we need to put it in the
GSI IRQ routing table too.
There is a per-VM capability by which the kernel signals the need for
a device ID, so check this and put the device ID into the routing
table if needed.
For PCI devices we take the bus/device/function triplet and and that
to the routing setup call.

Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
 hw/pci-shmem.c    |  3 ++-
 include/kvm/irq.h |  2 +-
 irq.c             | 24 ++++++++++++++++++++++--
 virtio/pci.c      |  6 ++++--
 4 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/hw/pci-shmem.c b/hw/pci-shmem.c
index 7ce98cb..512b5b0 100644
--- a/hw/pci-shmem.c
+++ b/hw/pci-shmem.c
@@ -135,7 +135,8 @@ int pci_shmem__get_local_irqfd(struct kvm *kvm)
 			return fd;
 
 		if (pci_shmem_pci_device.msix.ctrl & cpu_to_le16(PCI_MSIX_FLAGS_ENABLE)) {
-			gsi = irq__add_msix_route(kvm, &msix_table[0].msg);
+			gsi = irq__add_msix_route(kvm, &msix_table[0].msg,
+						  pci_shmem_device.dev_num << 3);
 			if (gsi < 0)
 				return gsi;
 		} else {
diff --git a/include/kvm/irq.h b/include/kvm/irq.h
index f35eb7e..ee059e3 100644
--- a/include/kvm/irq.h
+++ b/include/kvm/irq.h
@@ -20,7 +20,7 @@ int irq__init(struct kvm *kvm);
 int irq__exit(struct kvm *kvm);
 
 int irq__allocate_routing_entry(void);
-int irq__add_msix_route(struct kvm *kvm, struct msi_msg *msg);
+int irq__add_msix_route(struct kvm *kvm, struct msi_msg *msg, u32 device_id);
 void irq__update_msix_route(struct kvm *kvm, u32 gsi, struct msi_msg *msg);
 
 #endif
diff --git a/irq.c b/irq.c
index 25ac8d7..ea365de 100644
--- a/irq.c
+++ b/irq.c
@@ -62,7 +62,21 @@ static bool check_for_irq_routing(struct kvm *kvm)
 	return has_irq_routing > 0;
 }
 
-int irq__add_msix_route(struct kvm *kvm, struct msi_msg *msg)
+static bool check_for_msi_devid(struct kvm *kvm)
+{
+	static int needs_devid = 0;
+
+	if (needs_devid == 0) {
+		if (kvm__supports_vm_extension(kvm, KVM_CAP_MSI_DEVID))
+			needs_devid = 1;
+		else
+			needs_devid = -1;
+	}
+
+	return needs_devid > 0;
+}
+
+int irq__add_msix_route(struct kvm *kvm, struct msi_msg *msg, u32 device_id)
 {
 	int r;
 
@@ -73,7 +87,7 @@ int irq__add_msix_route(struct kvm *kvm, struct msi_msg *msg)
 	if (r)
 		return r;
 
-	irq_routing->entries[irq_routing->nr++] =
+	irq_routing->entries[irq_routing->nr] =
 		(struct kvm_irq_routing_entry) {
 			.gsi = next_gsi,
 			.type = KVM_IRQ_ROUTING_MSI,
@@ -82,6 +96,12 @@ int irq__add_msix_route(struct kvm *kvm, struct msi_msg *msg)
 			.u.msi.data = msg->data,
 		};
 
+	if (check_for_msi_devid(kvm)) {
+		irq_routing->entries[irq_routing->nr].flags = KVM_MSI_VALID_DEVID;
+		irq_routing->entries[irq_routing->nr].u.msi.devid = device_id;
+	}
+	irq_routing->nr++;
+
 	r = ioctl(kvm->vm_fd, KVM_SET_GSI_ROUTING, irq_routing);
 	if (r)
 		return r;
diff --git a/virtio/pci.c b/virtio/pci.c
index e92a2df..f12773f 100644
--- a/virtio/pci.c
+++ b/virtio/pci.c
@@ -191,7 +191,8 @@ static bool virtio_pci__specific_io_out(struct kvm *kvm, struct virtio_device *v
 				break;
 
 			gsi = irq__add_msix_route(kvm,
-						  &vpci->msix_table[vec].msg);
+						  &vpci->msix_table[vec].msg,
+						  vpci->dev_hdr.dev_num << 3);
 			if (gsi >= 0)
 				vpci->config_gsi = gsi;
 			break;
@@ -203,7 +204,8 @@ static bool virtio_pci__specific_io_out(struct kvm *kvm, struct virtio_device *v
 				break;
 
 			gsi = irq__add_msix_route(kvm,
-						  &vpci->msix_table[vec].msg);
+						  &vpci->msix_table[vec].msg,
+						  vpci->dev_hdr.dev_num << 3);
 			if (gsi < 0)
 				break;
 			vpci->gsis[vpci->queue_selector] = gsi;
-- 
2.3.5