This patch adds and documents a new attribute
KVM_DEV_VFIO_DEVICE_POSTING_IRQ in KVM_DEV_VFIO_DEVICE group.
This new attribute is used for VT-d Posted-Interrupts.
When guest OS changes the interrupt configuration for an
assigned device, such as, MSI/MSIx data/address fields,
QEMU will use this IRQ attribute to tell KVM to update the
related IRTE according the VT-d Posted-Interrrupts Specification,
such as, the guest vector should be updated in the related IRTE.
Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx>
---
Documentation/virtual/kvm/devices/vfio.txt | 9 +++++++++
include/uapi/linux/kvm.h | 10 ++++++++++
2 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/Documentation/virtual/kvm/devices/vfio.txt b/Documentation/virtual/kvm/devices/vfio.txt
index f7aff29..39dee86 100644
--- a/Documentation/virtual/kvm/devices/vfio.txt
+++ b/Documentation/virtual/kvm/devices/vfio.txt
@@ -42,3 +42,12 @@ activated before VFIO_DEVICE_SET_IRQS has been called to trigger the IRQ
or associate an eventfd to it. Unforwarding can only be called while the
signaling has been disabled with VFIO_DEVICE_SET_IRQS. If this condition is
not satisfied, the command returns an -EBUSY.
+
+ KVM_DEV_VFIO_DEVICE_POSTING_IRQ: Use posted interrtups mechanism to post
+ the IRQ to guests.
+For this attribute, kvm_device_attr.addr points to a kvm_posted_intr struct.
+
+When guest OS changes the interrupt configuration for an assigned device,
+such as, MSI/MSIx data/address fields, QEMU will use this IRQ attribute
+to tell KVM to update the related IRTE according the VT-d Posted-Interrrupts
+Specification, such as, the guest vector should be updated in the related IRTE.
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index a269a42..e5f86ad 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -949,6 +949,7 @@ struct kvm_device_attr {
#define KVM_DEV_VFIO_DEVICE 2
#define KVM_DEV_VFIO_DEVICE_FORWARD_IRQ 1
#define KVM_DEV_VFIO_DEVICE_UNFORWARD_IRQ 2
+#define KVM_DEV_VFIO_DEVICE_POSTING_IRQ 3
enum kvm_device_type {
KVM_DEV_TYPE_FSL_MPIC_20 = 1,
@@ -973,6 +974,15 @@ struct kvm_arch_forwarded_irq {
__u32 gsi; /* gsi, ie. virtual IRQ number */
};
+struct kvm_posted_intr {
+ __u32 argsz;
+ __u32 fd; /* file descriptor of the VFIO device */
+ __u32 index; /* VFIO device IRQ index */
+ __u32 start;
+ __u32 count;
+ int virq[0]; /* gsi, ie. virtual IRQ number */
+};
+
/*
* ioctls for VM fds
*/
--
1.7.1
--
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