RE: [PATCH v6 05/24] kvm/vfio: Accept vfio device file from userspace

Liu, Yi L
2023-03-28T03:48:52Z

> From: Xu, Yilun <yilun.xu@intel.com>
> Sent: Wednesday, March 22, 2023 10:11 PM
>
> On 2023-03-08 at 05:28:44 -0800, Yi Liu wrote:
> > This defines KVM_DEV_VFIO_FILE* and make alias with
> KVM_DEV_VFIO_GROUP*.
> > Old userspace uses KVM_DEV_VFIO_GROUP* works as well.
> >
> > Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> > Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> > Tested-by: Terrence Xu <terrence.xu@intel.com>
> > Tested-by: Nicolin Chen <nicolinc@nvidia.com>
> > Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
> > ---
> > Documentation/virt/kvm/devices/vfio.rst | 52 +++++++++++++++++--------
> > include/uapi/linux/kvm.h | 16 ++++++--
> > virt/kvm/vfio.c | 16 ++++----
> > 3 files changed, 55 insertions(+), 29 deletions(-)
> >
> > diff --git a/Documentation/virt/kvm/devices/vfio.rst
> b/Documentation/virt/kvm/devices/vfio.rst
> > index 79b6811bb4f3..5b05b48abaab 100644
> > --- a/Documentation/virt/kvm/devices/vfio.rst
> > +++ b/Documentation/virt/kvm/devices/vfio.rst
> > @@ -9,24 +9,37 @@ 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.
> > +tracks VFIO files (group or device) in use by the VM and features
> > +of those groups/devices important to the correctness and acceleration
> > +of the VM. As groups/devices 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 file is held by KVM.
> >
> > Groups:
> > - KVM_DEV_VFIO_GROUP
> > -
> > -KVM_DEV_VFIO_GROUP attributes:
> > - KVM_DEV_VFIO_GROUP_ADD: Add a VFIO group to VFIO-KVM device
> tracking
> > - kvm_device_attr.addr points to an int32_t file descriptor
> > - for the VFIO group.
> > - KVM_DEV_VFIO_GROUP_DEL: Remove a VFIO group from VFIO-KVM
> device tracking
> > - kvm_device_attr.addr points to an int32_t file descriptor
> > - for the VFIO group.
> > - KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: attaches a guest visible TCE
> table
> > + KVM_DEV_VFIO_FILE
> > + alias: KVM_DEV_VFIO_GROUP
> > +
> > +KVM_DEV_VFIO_FILE attributes:
> > + KVM_DEV_VFIO_FILE_ADD: Add a VFIO file (group/device) to VFIO-KVM
> device
> > + tracking
> > +
> > + alias: KVM_DEV_VFIO_GROUP_ADD
> > +
> > + kvm_device_attr.addr points to an int32_t file descriptor for the
> > + VFIO file.
>
> A blank line here to be consistent with other attibutes.
>
> > + KVM_DEV_VFIO_FILE_DEL: Remove a VFIO file (group/device) from
> VFIO-KVM
> > + device tracking
> > +
> > + alias: KVM_DEV_VFIO_GROUP_DEL
> > +
> > + kvm_device_attr.addr points to an int32_t file descriptor for the
> > + VFIO file.
> > +
> > + KVM_DEV_VFIO_FILE_SET_SPAPR_TCE: attaches a guest visible TCE
> table
> > allocated by sPAPR KVM.
> > +
> > + alias: KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE
> > +
> > kvm_device_attr.addr points to a struct::
> >
> > struct kvm_vfio_spapr_tce {
> > @@ -40,9 +53,14 @@ KVM_DEV_VFIO_GROUP attributes:
> > - @tablefd is a file descriptor for a TCE table allocated via
> > KVM_CREATE_SPAPR_TCE.
> >
> > + only accepts vfio group file as SPAPR has no iommufd support
> > +
> > ::
> >
> > -The GROUP_ADD operation above should be invoked prior to accessing
> the
> > +The FILE/GROUP_ADD operation above should be invoked prior to
> accessing the
> > device file descriptor via VFIO_GROUP_GET_DEVICE_FD in order to
> support
> > drivers which require a kvm pointer to be set in their .open_device()
> > -callback.
> > +callback. It is the same for device file descriptor via character device
> > +open which gets device access via VFIO_DEVICE_BIND_IOMMUFD. For
> such file
> > +descriptors, FILE_ADD should be invoked before
> VFIO_DEVICE_BIND_IOMMUFD
> > +to support the drivers mentioned in piror sentence as well.
>
> s/piror/prior

Fixed in v8, thanks.