On Tue, 2014-11-25 at 16:01 +0100, Eric Auger wrote:
> On 11/25/2014 01:23 PM, 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..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 */
> > +};
> Hi Feng,
>
> This struct could be used by arm code too. If Alex agrees I could use
> that one instead. We just need to find a common sensible name
Yep, the interface might as well support batch setup. The vfio code
uses -1 for teardown if we want to avoid FORWARD vs UNFORWARD we could
let the data in the structure define which operation to do. Ideally the
code in virt/kvm/vfio.c would be almost entirely shared and just make
different arch_foo() callouts. The PCI smarts in 2/2 here should
probably be moved out to that same arch_ code. Thanks,
Alex
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