> -----Original Message----- > From: Eric Auger [mailto:eric.auger@xxxxxxxxxx] > Sent: Thursday, June 11, 2015 9:38 PM > To: Wu, Feng; kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Cc: pbonzini@xxxxxxxxxx; mtosatti@xxxxxxxxxx; > alex.williamson@xxxxxxxxxx > Subject: Re: [v4 08/16] KVM: kvm-vfio: User API for IRQ forwarding > > Hi Feng, > On 06/11/2015 12:51 PM, Feng Wu wrote: > > From: Eric Auger <eric.auger@xxxxxxxxxx> > > > > This patch adds and documents a new KVM_DEV_VFIO_DEVICE group > > and 2 device attributes: KVM_DEV_VFIO_DEVICE_FORWARD_IRQ, > > KVM_DEV_VFIO_DEVICE_UNFORWARD_IRQ. The purpose is to be able > > to set a VFIO device IRQ as forwarded or not forwarded. > > the command takes as argument a handle to a new struct named > > kvm_vfio_dev_irq. > > > > Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx> > > --- > > Documentation/virtual/kvm/devices/vfio.txt | 34 > ++++++++++++++++++++++++------ > > include/uapi/linux/kvm.h | 12 +++++++++++ > > 2 files changed, 40 insertions(+), 6 deletions(-) > > > > diff --git a/Documentation/virtual/kvm/devices/vfio.txt > b/Documentation/virtual/kvm/devices/vfio.txt > > index ef51740..6186e6d 100644 > > --- a/Documentation/virtual/kvm/devices/vfio.txt > > +++ b/Documentation/virtual/kvm/devices/vfio.txt > > @@ -4,15 +4,20 @@ VFIO virtual device > > Device types supported: > > KVM_DEV_TYPE_VFIO > > > > -Only one VFIO instance may be created per VM. The created device > > -tracks VFIO groups in use by the VM and features of those groups > > -important to the correctness and acceleration of the VM. As groups > > -are enabled and disabled for use by the VM, KVM should be updated > > -about their presence. When registered with KVM, a reference to the > > -VFIO-group is held by KVM. > > +Only one VFIO instance may be created per VM. > > + > > +The created device tracks VFIO groups in use by the VM and features > > +of those groups important to the correctness and acceleration of > > +the VM. As groups are enabled and disabled for use by the VM, KVM > > +should be updated about their presence. When registered with KVM, > > +a reference to the VFIO-group is held by KVM. > > + > > +The device also enables to control some IRQ settings of VFIO devices: > > +forwarding/posting. > > > > Groups: > > KVM_DEV_VFIO_GROUP > > + KVM_DEV_VFIO_DEVICE > > > > KVM_DEV_VFIO_GROUP attributes: > > KVM_DEV_VFIO_GROUP_ADD: Add a VFIO group to VFIO-KVM device > tracking > > @@ -20,3 +25,20 @@ KVM_DEV_VFIO_GROUP attributes: > > > > For each, kvm_device_attr.addr points to an int32_t file descriptor > > for the VFIO group. > > + > > +KVM_DEV_VFIO_DEVICE attributes: > > + KVM_DEV_VFIO_DEVICE_FORWARD_IRQ: set a VFIO device IRQ as > forwarded > > + KVM_DEV_VFIO_DEVICE_UNFORWARD_IRQ: set a VFIO device IRQ as > not forwarded > > + > > +For each, kvm_device_attr.addr points to a kvm_vfio_dev_irq struct. > > + > > +When forwarded, a physical IRQ is completed by the guest and not by the > > +host. This requires HW support in the interrupt controller. > > + > > +Forwarding can only be set when the corresponding VFIO IRQ is not masked > > +(would it be through VFIO_DEVICE_SET_IRQS command or as a consequence > of this > > +IRQ being currently handled) or active at interrupt controller level. > > +In such a situation, -EAGAIN is returned. It is advised to to set the > > +forwarding before the VFIO signaling is set up, this avoids trial and errors. > > + > > +Unforwarding can happen at any time. > Unfortunately the above text is out of context of your series. If it > simplifies things take the ownership of that patch file and remove my > description of KVM_DEV_VFIO_DEVICE_FORWARD_IRQ. Oh, I didn't notice that. It is a good suggestion, Eric! Thanks, Feng > > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > > index 4b60056..798f3e4 100644 > > --- a/include/uapi/linux/kvm.h > > +++ b/include/uapi/linux/kvm.h > > @@ -999,6 +999,9 @@ struct kvm_device_attr { > > #define KVM_DEV_VFIO_GROUP 1 > > #define KVM_DEV_VFIO_GROUP_ADD 1 > > #define KVM_DEV_VFIO_GROUP_DEL 2 > > +#define KVM_DEV_VFIO_DEVICE 2 > > +#define KVM_DEV_VFIO_DEVICE_FORWARD_IRQ 1 > > +#define KVM_DEV_VFIO_DEVICE_UNFORWARD_IRQ 2 > same here > Best Regards > > Eric > > > > enum kvm_device_type { > > KVM_DEV_TYPE_FSL_MPIC_20 = 1, > > @@ -1018,6 +1021,15 @@ enum kvm_device_type { > > KVM_DEV_TYPE_MAX, > > }; > > > > +struct kvm_vfio_dev_irq { > > + __u32 argsz; /* structure length */ > > + __u32 fd; /* file descriptor of the VFIO device */ > > + __u32 index; /* VFIO device IRQ index */ > > + __u32 start; /* start of subindex range */ > > + __u32 count; /* size of subindex range */ > > + __u32 gsi[]; /* gsi, ie. virtual IRQ number */ > > +}; > > + > > /* > > * ioctls for VM fds > > */ > > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
