[PATCH v2 1/7] KVM: api: introduce KVM_IRQ_ROUTING_EXTENDED_MSI

[Eric Auger]

On ARM, the MSI msg (address and data) comes along with
out-of-band device ID information. The device ID encodes the
device that writes the MSI msg. Let's convey the device id in
kvm_irq_routing_msi and use a new routing entry type to
indicate the devid is populated.

Signed-off-by: Eric Auger <eric.auger at linaro.org>

---

v1 -> v2:
- devid id passed in kvm_irq_routing_msi instead of in
  kvm_irq_routing_entry

RFC -> PATCH
- remove kvm_irq_routing_extended_msi and use union instead
---
 Documentation/virtual/kvm/api.txt | 10 +++++++++-
 include/uapi/linux/kvm.h          |  6 +++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index bea8de7..3d920cd 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1453,6 +1453,7 @@ struct kvm_irq_routing_entry {
 #define KVM_IRQ_ROUTING_IRQCHIP 1
 #define KVM_IRQ_ROUTING_MSI 2
 #define KVM_IRQ_ROUTING_S390_ADAPTER 3
+#define KVM_IRQ_ROUTING_EXTENDED_MSI 4
 
 No flags are specified so far, the corresponding field must be set to zero.
 
@@ -1465,9 +1466,16 @@ struct kvm_irq_routing_msi {
 	__u32 address_lo;
 	__u32 address_hi;
 	__u32 data;
-	__u32 pad;
+	union {
+		__u32 pad;
+		__u32 devid;
+	};
 };
 
+for KVM_IRQ_ROUTING_EXTENDED_MSI routing entry type, the kvm_irq_routing_msi
+routing entry is used and devid is populated with the device ID that wrote
+the MSI message. For PCI, this is usually a BFD identifier in the lower 16 bits.
+
 struct kvm_irq_routing_s390_adapter {
 	__u64 ind_addr;
 	__u64 summary_addr;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 9a261e5..39ec164 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -829,7 +829,10 @@ struct kvm_irq_routing_msi {
 	__u32 address_lo;
 	__u32 address_hi;
 	__u32 data;
-	__u32 pad;
+	union {
+		__u32 pad;
+		__u32 devid;
+	};
 };
 
 struct kvm_irq_routing_s390_adapter {
@@ -844,6 +847,7 @@ struct kvm_irq_routing_s390_adapter {
 #define KVM_IRQ_ROUTING_IRQCHIP 1
 #define KVM_IRQ_ROUTING_MSI 2
 #define KVM_IRQ_ROUTING_S390_ADAPTER 3
+#define KVM_IRQ_ROUTING_EXTENDED_MSI 4
 
 struct kvm_irq_routing_entry {
 	__u32 gsi;
-- 
1.9.1