Hi Feng,
On 12/03/2014 08:39 AM, Feng Wu wrote:
> 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...@intel.com>
> ---
> 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..41e12b7 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
typo
> + the IRQ to guests.
> +For this attribute, kvm_device_attr.addr points to a kvm_vfio_dev_irq 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.
For my curiosity are there any restrictions about the instant at which
the change can be done?
I do not get here how you deactivate the posting?
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index a269a42..7d98650 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
Maybe we should align our naming verb vs verbing here?
Best Regards
Eric
>
> 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_vfio_dev_irq {
> + __u32 argsz;
> + __u32 fd; /* file descriptor of the VFIO device */
> + __u32 index; /* VFIO device IRQ index */
> + __u32 start;
> + __u32 count;
> + __u32 gsi[]; /* gsi, ie. virtual IRQ number */
> +};
> +
> /*
> * ioctls for VM fds
> */
>
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