On Wed, 29 Jan 2020 04:11:46 -0800 "Liu, Yi L" <yi.l.liu@xxxxxxxxx> wrote: > From: Liu Yi L <yi.l.liu@xxxxxxxxx> > > The PASID quota is per-application (VM) according to vfio's PASID > management rule. For better flexibility, quota shall be user tunable > . This patch provides a VFIO based user interface for which quota can > be adjusted. However, quota cannot be adjusted downward below the > number of outstanding PASIDs. > > This patch only makes the per-VM PASID quota tunable. While for the > way to tune the default PASID quota, it may require a new vfio module > option or other way. This may be another patchset in future. If we give an unprivileged user the ability to increase their quota, why do we even have a quota at all? I figured we were going to have a module option tunable so its under the control of the system admin. Thanks, Alex > > Previous discussions: > https://patchwork.kernel.org/patch/11209429/ > > Cc: Kevin Tian <kevin.tian@xxxxxxxxx> > CC: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > Cc: Alex Williamson <alex.williamson@xxxxxxxxxx> > Cc: Eric Auger <eric.auger@xxxxxxxxxx> > Cc: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx> > Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx> > --- > drivers/vfio/vfio_iommu_type1.c | 33 +++++++++++++++++++++++++++++++++ > include/uapi/linux/vfio.h | 22 ++++++++++++++++++++++ > 2 files changed, 55 insertions(+) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index e836d04..1cf75f5 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -2243,6 +2243,27 @@ static int vfio_iommu_type1_pasid_free(struct vfio_iommu *iommu, > return ret; > } > > +static int vfio_iommu_type1_set_pasid_quota(struct vfio_iommu *iommu, > + u32 quota) > +{ > + struct vfio_mm *vmm = iommu->vmm; > + int ret = 0; > + > + mutex_lock(&iommu->lock); > + mutex_lock(&vmm->pasid_lock); > + if (vmm->pasid_count > quota) { > + ret = -EINVAL; > + goto out_unlock; > + } > + vmm->pasid_quota = quota; > + ret = quota; > + > +out_unlock: > + mutex_unlock(&vmm->pasid_lock); > + mutex_unlock(&iommu->lock); > + return ret; > +} > + > static long vfio_iommu_type1_ioctl(void *iommu_data, > unsigned int cmd, unsigned long arg) > { > @@ -2389,6 +2410,18 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, > default: > return -EINVAL; > } > + } else if (cmd == VFIO_IOMMU_SET_PASID_QUOTA) { > + struct vfio_iommu_type1_pasid_quota quota; > + > + minsz = offsetofend(struct vfio_iommu_type1_pasid_quota, > + quota); > + > + if (copy_from_user("a, (void __user *)arg, minsz)) > + return -EFAULT; > + > + if (quota.argsz < minsz) > + return -EINVAL; > + return vfio_iommu_type1_set_pasid_quota(iommu, quota.quota); > } > > return -ENOTTY; > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > index 298ac80..d4bf415 100644 > --- a/include/uapi/linux/vfio.h > +++ b/include/uapi/linux/vfio.h > @@ -835,6 +835,28 @@ struct vfio_iommu_type1_pasid_request { > */ > #define VFIO_IOMMU_PASID_REQUEST _IO(VFIO_TYPE, VFIO_BASE + 22) > > +/** > + * @quota: the new pasid quota which a userspace application (e.g. VM) > + * is configured. > + */ > +struct vfio_iommu_type1_pasid_quota { > + __u32 argsz; > + __u32 flags; > + __u32 quota; > +}; > + > +/** > + * VFIO_IOMMU_SET_PASID_QUOTA - _IOW(VFIO_TYPE, VFIO_BASE + 23, > + * struct vfio_iommu_type1_pasid_quota) > + * > + * Availability of this feature depends on PASID support in the device, > + * its bus, the underlying IOMMU and the CPU architecture. In VFIO, it > + * is available after VFIO_SET_IOMMU. > + * > + * returns: latest quota on success, -errno on failure. > + */ > +#define VFIO_IOMMU_SET_PASID_QUOTA _IO(VFIO_TYPE, VFIO_BASE + 23) > + > /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */ > > /*
