> From: Auger Eric [mailto:eric.auger@xxxxxxxxxx] > Sent: Thursday, July 18, 2019 6:17 PM > To: Liu, Yi L <yi.l.liu@xxxxxxxxx>; alex.williamson@xxxxxxxxxx > Subject: Re: [RFC v1 4/4] vfio/type1: bind guest pasid (guest page tables) to host > > Yi, > > On 7/5/19 1:06 PM, Liu, Yi L wrote: > > From: Liu Yi L <yi.l.liu@xxxxxxxxx> > > > > This patch adds vfio support to bind guest translation structure to > > host iommu. VFIO exposes iommu programming capability to user- space. > > Guest is a user-space application in host under KVM solution. > > For SVA usage in Virtual Machine, guest owns GVA->GPA translation > > structure. And this part should be passdown to host to enable nested > > translation (or say two stage translation). This patch reuses the > > VFIO_IOMMU_BIND proposal from Jean-Philippe Brucker, and adds new bind > > type for binding guest owned translation structure to host. > > > > *) Add two new ioctls for VFIO containers. > > > > - VFIO_IOMMU_BIND: for bind request from userspace, it could be > > bind a process to a pasid or bind a guest pasid > > to a device, this is indicated by type > > - VFIO_IOMMU_UNBIND: for unbind request from userspace, it could be > > unbind a process to a pasid or unbind a guest pasid > > to a device, also indicated by type > > - Bind type: > > VFIO_IOMMU_BIND_PROCESS: user-space request to bind a process > > to a device > > VFIO_IOMMU_BIND_GUEST_PASID: bind guest owned translation > > structure to host iommu. e.g. guest page table > You may add that only VFIO_IOMMU_BIND_GUEST_PASID gets implemented in this > patch Good catch:-). > > > > *) Code logic in vfio_iommu_type1_ioctl() to handle > > VFIO_IOMMU_BIND/UNBIND > > > > Cc: Kevin Tian <kevin.tian@xxxxxxxxx> > > Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx> > > Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx> > > Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > > --- > > drivers/vfio/vfio_iommu_type1.c | 151 > ++++++++++++++++++++++++++++++++++++++++ > > include/uapi/linux/vfio.h | 56 +++++++++++++++ > > 2 files changed, 207 insertions(+) > > > > diff --git a/drivers/vfio/vfio_iommu_type1.c > > b/drivers/vfio/vfio_iommu_type1.c index d5e0c01..57826ed 100644 > > --- a/drivers/vfio/vfio_iommu_type1.c > > +++ b/drivers/vfio/vfio_iommu_type1.c > > @@ -1920,6 +1920,119 @@ static int vfio_iommu_type1_pasid_free(struct > vfio_iommu *iommu, int pasid) > > return ret; > > } > > > > +static int vfio_bind_gpasid_fn(struct device *dev, void *data) { > > + struct iommu_domain *domain = iommu_get_domain_for_dev(dev); > > + struct vfio_iommu_type1_bind_guest_pasid *guest_bind = data; > > + > > + return iommu_sva_bind_gpasid(domain, dev, &guest_bind->bind_data); } > > + > > +static int vfio_unbind_gpasid_fn(struct device *dev, void *data) { > > + struct iommu_domain *domain = iommu_get_domain_for_dev(dev); > > + struct vfio_iommu_type1_bind_guest_pasid *guest_bind = data; > > + > > + return iommu_sva_unbind_gpasid(domain, dev, > > + guest_bind->bind_data.hpasid); > > +} > > + > > +/* > > + * unbind specific gpasid, caller of this function requires hold > > + * vfio_iommu->lock > > + */ > > +static long vfio_iommu_type1_do_guest_unbind(struct vfio_iommu *iommu, > > + struct vfio_iommu_type1_bind_guest_pasid *guest_bind) { > > + struct vfio_domain *domain; > > + struct vfio_group *group; > > + int ret = 0; > > + > > + if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) { > > + ret = -EINVAL; > > + goto out; > > + } > > + > > + list_for_each_entry(domain, &iommu->domain_list, next) { > > + list_for_each_entry(group, &domain->group_list, next) { > > + ret = iommu_group_for_each_dev(group->iommu_group, > > + guest_bind, vfio_unbind_gpasid_fn); > can it fail individually, in which case we end up with something half unset or it is safe? > A comment may be worth. thanks, good suggestion. Actually, we have an assumption that for devices which belong to non-singleton group, we should not enable PASID capability. So may not fail individually. But yes, a comment would be needed here. > > + if (ret) > > + goto out; > > + } > > + } > you may use vfio_iommu_lookup_dev() introduced in [RFC v1 2/4] vfio: > VFIO_IOMMU_CACHE_INVALIDATE yes, let me do it next version. :-) > > + > > + return 0; > not needed > > + > > +out: > > + return ret; > > +} > > + > > +static long vfio_iommu_type1_bind_gpasid(struct vfio_iommu *iommu, > > + void __user *arg, > > + struct vfio_iommu_type1_bind *bind) { > > + struct vfio_iommu_type1_bind_guest_pasid guest_bind; > > + struct vfio_domain *domain; > > + struct vfio_group *group; > > + unsigned long minsz; > > + int ret = 0; > > + > > + minsz = sizeof(*bind) + sizeof(guest_bind); > > + if (bind->argsz < minsz) > > + return -EINVAL; > > + > > + if (copy_from_user(&guest_bind, arg, sizeof(guest_bind))) > > + return -EFAULT; > > + > > + mutex_lock(&iommu->lock); > > + if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) { > > + ret = -EINVAL; > > + goto out_unlock; > > + } > > + > > + list_for_each_entry(domain, &iommu->domain_list, next) { > > + list_for_each_entry(group, &domain->group_list, next) { > > + ret = iommu_group_for_each_dev(group->iommu_group, > > + &guest_bind, vfio_bind_gpasid_fn); > > + if (ret) > > + goto out_unbind; > use vfio_iommu_lookup_dev got it. ~ > > + } > > > + } > > + > > + mutex_unlock(&iommu->lock); > > + return 0; > > + > > +out_unbind: > > + /* Undo all binds that already succeeded */ > > + vfio_iommu_type1_do_guest_unbind(iommu, &guest_bind); > > + > > +out_unlock: > > + mutex_unlock(&iommu->lock); > > + return ret; > > +} > > + > > +static long vfio_iommu_type1_unbind_gpasid(struct vfio_iommu *iommu, > > + void __user *arg, > > + struct vfio_iommu_type1_bind *bind) { > > + struct vfio_iommu_type1_bind_guest_pasid guest_bind; > > + unsigned long minsz; > > + int ret = 0; > nit: init not needed yeah, nice catch. > > + > > + minsz = sizeof(*bind) + sizeof(guest_bind); > > + if (bind->argsz < minsz) > > + return -EINVAL; > > + > > + if (copy_from_user(&guest_bind, arg, sizeof(guest_bind))) > > + return -EFAULT; > > + > > + mutex_lock(&iommu->lock); > > + ret = vfio_iommu_type1_do_guest_unbind(iommu, &guest_bind); > > + mutex_unlock(&iommu->lock); > > + return ret; > > +} > > + > > static long vfio_iommu_type1_ioctl(void *iommu_data, > > unsigned int cmd, unsigned long arg) { @@ - > 2061,6 +2174,44 @@ > > static long vfio_iommu_type1_ioctl(void *iommu_data, > > default: > > return -EINVAL; > > } > > + > > + } else if (cmd == VFIO_IOMMU_BIND) { > > + struct vfio_iommu_type1_bind bind; > > + > > + minsz = offsetofend(struct vfio_iommu_type1_bind, bind_type); > > + > > + if (copy_from_user(&bind, (void __user *)arg, minsz)) > > + return -EFAULT; > > + > > + if (bind.argsz < minsz) > > + return -EINVAL; > > + > > + switch (bind.bind_type) { > > + case VFIO_IOMMU_BIND_GUEST_PASID: > > + return vfio_iommu_type1_bind_gpasid(iommu, > > + (void __user *)(arg + minsz), &bind); > > + default: > > + return -EINVAL; > > + } > > + > > + } else if (cmd == VFIO_IOMMU_UNBIND) { > > + struct vfio_iommu_type1_bind bind; > > + > > + minsz = offsetofend(struct vfio_iommu_type1_bind, bind_type); > > + > > + if (copy_from_user(&bind, (void __user *)arg, minsz)) > > + return -EFAULT; > > + > > + if (bind.argsz < minsz) > > + return -EINVAL; > > + > > + switch (bind.bind_type) { > > + case VFIO_IOMMU_BIND_GUEST_PASID: > > + return vfio_iommu_type1_unbind_gpasid(iommu, > > + (void __user *)(arg + minsz), &bind); > > + default: > > + return -EINVAL; > > + } > > } > > > > return -ENOTTY; > > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > > index af03c9f..4167bbd 100644 > > --- a/include/uapi/linux/vfio.h > > +++ b/include/uapi/linux/vfio.h > > @@ -823,6 +823,62 @@ struct vfio_iommu_type1_pasid_request { > > */ > > #define VFIO_IOMMU_PASID_REQUEST _IO(VFIO_TYPE, VFIO_BASE + 27) > > > > +/* > > + * In guest use of SVA, the first level page tables is managed by the guest. > > + * we can either bind guest PASID table or explicitly bind a PASID > > +with guest > > + * page table. > > + */ > > +struct vfio_iommu_type1_bind_guest_pasid { > > + struct gpasid_bind_data bind_data; > > +}; > do you need this encapsulation? Why not directly using iommu.h uapi struct? yeah, at first I want to cover guest pasid table bind. but now, I agree this may be not necessary. :-) > > + > > +enum vfio_iommu_bind_type { > > + VFIO_IOMMU_BIND_PROCESS, > > + VFIO_IOMMU_BIND_GUEST_PASID, > > +}; > > + > > +/* > > + * Supported types: > > + * - VFIO_IOMMU_BIND_PROCESS: bind native process, which takes > > + * vfio_iommu_type1_bind_process in data. > > + * - VFIO_IOMMU_BIND_GUEST_PASID: bind guest pasid, which invoked > > + * by guest process binding, it takes > > + * vfio_iommu_type1_bind_guest_pasid in data. > > + */ > > +struct vfio_iommu_type1_bind { > > + __u32 argsz; > > + enum vfio_iommu_bind_type bind_type; > The rest of the API does not use enum directly in structs. __u8/__u32? If using __u8/__u32, it would introduce some bit flags. e.g. bit 0 for bind_gpasid, bit 1 for bind process. If so, it may be possible that user space pass both bit 0 and bit 1 as set. Then it would be a trouble. Enum may avoid it. Not sure if such case is critical. If not, I'm willing to use __u8/__u32. :-) Thanks very much for your review, Eric. Let me address the comments in next version. Regards, Yi Liu > > + __u8 data[]; > > +}; > > + > > +/* > > + * VFIO_IOMMU_BIND - _IOWR(VFIO_TYPE, VFIO_BASE + 28, struct > > +vfio_iommu_bind) > > + * > > + * Manage address spaces of devices in this container. Initially a > > +TYPE1 > > + * container can only have one address space, managed with > > + * VFIO_IOMMU_MAP/UNMAP_DMA. > > + * > > + * An IOMMU of type VFIO_TYPE1_NESTING_IOMMU can be managed by both > > +MAP/UNMAP > > + * and BIND ioctls at the same time. MAP/UNMAP acts on the stage-2 > > +(host) page > > + * tables, and BIND manages the stage-1 (guest) page tables. Other > > +types of > > + * IOMMU may allow MAP/UNMAP and BIND to coexist, where MAP/UNMAP > > +controls > > + * non-PASID traffic and BIND controls PASID traffic. But this > > +depends on the > > + * underlying IOMMU architecture and isn't guaranteed. > > + * > > + * Availability of this feature depends on the device, its bus, the > > +underlying > > + * IOMMU and the CPU architecture. > > + * > > + * returns: 0 on success, -errno on failure. > > + */ > > +#define VFIO_IOMMU_BIND _IO(VFIO_TYPE, VFIO_BASE + 28) > > + > > +/* > > + * VFIO_IOMMU_UNBIND - _IOWR(VFIO_TYPE, VFIO_BASE + 29, struct > > +vfio_iommu_bind) > > + * > > + * Undo what was done by the corresponding VFIO_IOMMU_BIND ioctl. > > + */ > > +#define VFIO_IOMMU_UNBIND _IO(VFIO_TYPE, VFIO_BASE + 29) > > + > > /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU > > -------- */ > > > > /* > > > > Thanks > > Eric
