Thread (52 messages) 52 messages, 5 authors, 2015-07-07

[PATCH 1/7] KVM: api: add kvm_irq_routing_extended_msi

From: Pavel Fedin <hidden>
Date: 2015-07-02 07:26:43
Also in: kvm, kvmarm, lkml

 Hello!
quoted hunk ↗ jump to hunk
-----Original Message-----
From: kvm-owner at vger.kernel.org [mailto:kvm-owner at vger.kernel.org] On Behalf Of Eric Auger
Sent: Monday, June 29, 2015 6:37 PM
To: eric.auger at st.com; eric.auger at linaro.org; linux-arm-kernel at lists.infradead.org;
marc.zyngier at arm.com; christoffer.dall at linaro.org; andre.przywara at arm.com;
kvmarm at lists.cs.columbia.edu; kvm at vger.kernel.org
Cc: linux-kernel at vger.kernel.org; patches at linaro.org; p.fedin at samsung.com; pbonzini at redhat.com
Subject: [PATCH 1/7] KVM: api: add kvm_irq_routing_extended_msi

On ARM, the MSI msg (address and data) comes along with
out-of-band device ID information. The device ID encodes the device
that composes the MSI msg. Let's create a new routing entry type,
dubbed KVM_IRQ_ROUTING_EXTENDED_MSI and use the __u32 pad space
to convey the device ID.

Signed-off-by: Eric Auger <redacted>

---

RFC -> PATCH
- remove kvm_irq_routing_extended_msi and use union instead
---
 Documentation/virtual/kvm/api.txt | 9 ++++++++-
 include/uapi/linux/kvm.h          | 6 +++++-
 2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index d20fd94..6426ae9 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1414,7 +1414,10 @@ struct kvm_irq_routing_entry {
 	__u32 gsi;
 	__u32 type;
 	__u32 flags;
-	__u32 pad;
+	union {
+		__u32 pad;
+		__u32 devid;
+	};
 	union {
 		struct kvm_irq_routing_irqchip irqchip;
 		struct kvm_irq_routing_msi msi;
 devid is actually a part of MSI bunch. Shouldn't it be a part of struct kvm_irq_routing_msi then?
It also has reserved pad.
quoted hunk ↗ jump to hunk
@@ -1427,6 +1430,10 @@ 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
+
+In case of KVM_IRQ_ROUTING_EXTENDED_MSI routing type, devid is used to convey
+the device ID.

 No flags are specified so far, the corresponding field must be set to zero.
What if we use KVM_MSI_VALID_DEVID flag instead of new KVM_IRQ_ROUTING_EXTENDED_MSI definition? I
believe this would make an API more consistent and introduce less new definitions.
quoted hunk ↗ jump to hunk
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 2a23705..8484681 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -841,12 +841,16 @@ 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;
 	__u32 type;
 	__u32 flags;
-	__u32 pad;
+	union {
+		__u32 pad;
+		__u32 devid;
+	};
 	union {
 		struct kvm_irq_routing_irqchip irqchip;
 		struct kvm_irq_routing_msi msi;
--
1.9.1

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Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia
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