[PATCH v5 10/15] vfio/type1: Support binding guest page tables to PASID

Liu Yi L
2020-07-12T11:14:45Z

Nesting translation allows two-levels/stages page tables, with 1st level
for guest translations (e.g. GVA->GPA), 2nd level for host translations
(e.g. GPA->HPA). This patch adds interface for binding guest page tables
to a PASID. This PASID must have been allocated to user space before the
binding request.

Cc: Kevin Tian <kevin.tian@intel.com>
CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
v3 -> v4:
*) address comments from Alex on v3

v2 -> v3:
*) use __iommu_sva_unbind_gpasid() for unbind call issued by VFIO
https://lore.kernel.org/linux-iommu/1592931837-58223-6-git-send-email-jacob.jun.pan@linux.intel.com/

v1 -> v2:
*) rename subject from "vfio/type1: Bind guest page tables to host"
*) remove VFIO_IOMMU_BIND, introduce VFIO_IOMMU_NESTING_OP to support bind/
unbind guet page table
*) replaced vfio_iommu_for_each_dev() with a group level loop since this
series enforces one group per container w/ nesting type as start.
*) rename vfio_bind/unbind_gpasid_fn() to vfio_dev_bind/unbind_gpasid_fn()
*) vfio_dev_unbind_gpasid() always successful
*) use vfio_mm->pasid_lock to avoid race between PASID free and page table
bind/unbind
---
drivers/vfio/vfio_iommu_type1.c | 166 ++++++++++++++++++++++++++++++++++++++++
drivers/vfio/vfio_pasid.c | 26 +++++++
include/linux/vfio.h | 20 +++++
include/uapi/linux/vfio.h | 31 ++++++++
4 files changed, 243 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 55b4065..f0f21ff 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -149,6 +149,30 @@ struct vfio_regions {
#define DIRTY_BITMAP_PAGES_MAX ((u64)INT_MAX)
#define DIRTY_BITMAP_SIZE_MAX DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX)

+struct domain_capsule {
+ struct vfio_group *group;
+ struct iommu_domain *domain;
+ void *data;
+};
+
+/* iommu->lock must be held */
+static struct vfio_group *vfio_find_nesting_group(struct vfio_iommu *iommu)
+{
+ struct vfio_domain *d;
+ struct vfio_group *group = NULL;
+
+ if (!iommu->nesting_info)
+ return NULL;
+
+ /* only support singleton container with nesting type */
+ list_for_each_entry(d, &iommu->domain_list, next) {
+ list_for_each_entry(group, &d->group_list, next) {
+ break;
+ }
+ }
+ return group;
+}
+
static int put_pfn(unsigned long pfn, int prot);

static struct vfio_group *vfio_iommu_find_iommu_group(struct vfio_iommu *iommu,
@@ -2349,6 +2373,48 @@ static int vfio_iommu_resv_refresh(struct vfio_iommu *iommu,
return ret;
}

+static int vfio_dev_bind_gpasid_fn(struct device *dev, void *data)
+{
+ struct domain_capsule *dc = (struct domain_capsule *)data;
+ unsigned long arg = *(unsigned long *)dc->data;
+
+ return iommu_sva_bind_gpasid(dc->domain, dev, (void __user *)arg);
+}
+
+static int vfio_dev_unbind_gpasid_fn(struct device *dev, void *data)
+{
+ struct domain_capsule *dc = (struct domain_capsule *)data;
+ unsigned long arg = *(unsigned long *)dc->data;
+
+ iommu_sva_unbind_gpasid(dc->domain, dev, (void __user *)arg);
+ return 0;
+}
+
+static int __vfio_dev_unbind_gpasid_fn(struct device *dev, void *data)
+{
+ struct domain_capsule *dc = (struct domain_capsule *)data;
+ struct iommu_gpasid_bind_data *unbind_data =
+ (struct iommu_gpasid_bind_data *)dc->data;
+
+ __iommu_sva_unbind_gpasid(dc->domain, dev, unbind_data);
+ return 0;
+}
+
+static void vfio_group_unbind_gpasid_fn(ioasid_t pasid, void *data)
+{
+ struct domain_capsule *dc = (struct domain_capsule *)data;
+ struct iommu_gpasid_bind_data unbind_data;
+
+ unbind_data.argsz = offsetof(struct iommu_gpasid_bind_data, vendor);
+ unbind_data.flags = 0;
+ unbind_data.hpasid = pasid;
+
+ dc->data = &unbind_data;
+
+ iommu_group_for_each_dev(dc->group->iommu_group,
+ dc, __vfio_dev_unbind_gpasid_fn);
+}
+
static void vfio_iommu_type1_detach_group(void *iommu_data,
struct iommu_group *iommu_group)
{
@@ -2392,6 +2458,21 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
if (!group)
continue;

+ if (iommu->nesting_info && iommu->vmm &&
+ (iommu->nesting_info->features &
+ IOMMU_NESTING_FEAT_BIND_PGTBL)) {
+ struct domain_capsule dc = { .group = group,
+ .domain = domain->domain,
+ .data = NULL };
+
+ /*
+ * Unbind page tables bound with system wide PASIDs
+ * which are allocated to user space.
+ */
+ vfio_mm_for_each_pasid(iommu->vmm, &dc,
+ vfio_group_unbind_gpasid_fn);
+ }
+
vfio_iommu_detach_group(domain, group);
update_dirty_scope = !group->pinned_page_dirty_scope;
list_del(&group->next);
@@ -2938,6 +3019,89 @@ static int vfio_iommu_type1_pasid_request(struct vfio_iommu *iommu,
}
}

+static long vfio_iommu_handle_pgtbl_op(struct vfio_iommu *iommu,
+ bool is_bind, unsigned long arg)
+{
+ struct iommu_nesting_info *info;
+ struct domain_capsule dc = { .data = &arg };
+ struct vfio_group *group;
+ struct vfio_domain *domain;
+ int ret;
+
+ mutex_lock(&iommu->lock);
+
+ info = iommu->nesting_info;
+ if (!info || !(info->features & IOMMU_NESTING_FEAT_BIND_PGTBL)) {
+ ret = -EOPNOTSUPP;
+ goto out_unlock_iommu;
+ }
+
+ if (!iommu->vmm) {
+ ret = -EINVAL;
+ goto out_unlock_iommu;
+ }
+
+ group = vfio_find_nesting_group(iommu);
+ if (!group) {
+ ret = -EINVAL;
+ goto out_unlock_iommu;
+ }
+
+ domain = list_first_entry(&iommu->domain_list,
+ struct vfio_domain, next);
+ dc.group = group;
+ dc.domain = domain->domain;
+
+ /* Avoid race with other containers within the same process */
+ vfio_mm_pasid_lock(iommu->vmm);
+
+ if (is_bind) {
+ ret = iommu_group_for_each_dev(group->iommu_group, &dc,
+ vfio_dev_bind_gpasid_fn);
+ if (ret)
+ iommu_group_for_each_dev(group->iommu_group, &dc,
+ vfio_dev_unbind_gpasid_fn);
+ } else {
+ iommu_group_for_each_dev(group->iommu_group,
+ &dc, vfio_dev_unbind_gpasid_fn);
+ ret = 0;
+ }
+
+ vfio_mm_pasid_unlock(iommu->vmm);
+out_unlock_iommu:
+ mutex_unlock(&iommu->lock);
+ return ret;
+}
+
+static long vfio_iommu_type1_nesting_op(struct vfio_iommu *iommu,
+ unsigned long arg)
+{
+ struct vfio_iommu_type1_nesting_op hdr;
+ unsigned int minsz;
+ int ret;
+
+ minsz = offsetofend(struct vfio_iommu_type1_nesting_op, flags);
+
+ if (copy_from_user(&hdr, (void __user *)arg, minsz))
+ return -EFAULT;
+
+ if (hdr.argsz < minsz || hdr.flags & ~VFIO_NESTING_OP_MASK)
+ return -EINVAL;
+
+ switch (hdr.flags & VFIO_NESTING_OP_MASK) {
+ case VFIO_IOMMU_NESTING_OP_BIND_PGTBL:
+ ret = vfio_iommu_handle_pgtbl_op(iommu, true, arg + minsz);
+ break;
+ case VFIO_IOMMU_NESTING_OP_UNBIND_PGTBL:
+ ret = vfio_iommu_handle_pgtbl_op(iommu, false, arg + minsz);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+
static long vfio_iommu_type1_ioctl(void *iommu_data,
unsigned int cmd, unsigned long arg)
{
@@ -2956,6 +3120,8 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
return vfio_iommu_type1_dirty_pages(iommu, arg);
case VFIO_IOMMU_PASID_REQUEST:
return vfio_iommu_type1_pasid_request(iommu, arg);
+ case VFIO_IOMMU_NESTING_OP:
+ return vfio_iommu_type1_nesting_op(iommu, arg);
default:
return -ENOTTY;
}
diff --git a/drivers/vfio/vfio_pasid.c b/drivers/vfio/vfio_pasid.c
index ebec244..ecabaaa 100644
--- a/drivers/vfio/vfio_pasid.c
+++ b/drivers/vfio/vfio_pasid.c
@@ -216,6 +216,8 @@ void vfio_pasid_free_range(struct vfio_mm *vmm,
* IOASID core will notify PASID users (e.g. IOMMU driver) to
* teardown necessary structures depending on the to-be-freed
* PASID.
+ * Hold pasid_lock also avoids race with PASID usages like bind/
+ * unbind page tables to requested PASID.
*/
mutex_lock(&vmm->pasid_lock);
while ((vid = vfio_find_pasid(vmm, min, max)) != NULL)
@@ -224,6 +226,30 @@ void vfio_pasid_free_range(struct vfio_mm *vmm,
}
EXPORT_SYMBOL_GPL(vfio_pasid_free_range);

+int vfio_mm_for_each_pasid(struct vfio_mm *vmm, void *data,
+ void (*fn)(ioasid_t id, void *data))
+{
+ int ret;
+
+ mutex_lock(&vmm->pasid_lock);
+ ret = ioasid_set_for_each_ioasid(vmm->ioasid_sid, fn, data);
+ mutex_unlock(&vmm->pasid_lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(vfio_mm_for_each_pasid);
+
+void vfio_mm_pasid_lock(struct vfio_mm *vmm)
+{
+ mutex_lock(&vmm->pasid_lock);
+}
+EXPORT_SYMBOL_GPL(vfio_mm_pasid_lock);
+
+void vfio_mm_pasid_unlock(struct vfio_mm *vmm)
+{
+ mutex_unlock(&vmm->pasid_lock);
+}
+EXPORT_SYMBOL_GPL(vfio_mm_pasid_unlock);
+
static int __init vfio_pasid_init(void)
{
mutex_init(&vfio_mm_lock);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index a111108..2bc8347 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -105,6 +105,11 @@ int vfio_mm_ioasid_sid(struct vfio_mm *vmm);
extern int vfio_pasid_alloc(struct vfio_mm *vmm, int min, int max);
extern void vfio_pasid_free_range(struct vfio_mm *vmm,
ioasid_t min, ioasid_t max);
+extern int vfio_mm_for_each_pasid(struct vfio_mm *vmm, void *data,
+ void (*fn)(ioasid_t id, void *data));
+extern void vfio_mm_pasid_lock(struct vfio_mm *vmm);
+extern void vfio_mm_pasid_unlock(struct vfio_mm *vmm);
+
#else
static inline struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task)
{
@@ -129,6 +134,21 @@ static inline void vfio_pasid_free_range(struct vfio_mm *vmm,
ioasid_t min, ioasid_t max)
{
}
+
+static inline int vfio_mm_for_each_pasid(struct vfio_mm *vmm, void *data,
+ void (*fn)(ioasid_t id, void *data))
+{
+ return -ENOTTY;
+}
+
+static inline void vfio_mm_pasid_lock(struct vfio_mm *vmm)
+{
+}
+
+static inline void vfio_mm_pasid_unlock(struct vfio_mm *vmm)
+{
+}
+
#endif /* CONFIG_VFIO_PASID */

/*
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 96a115f..a8ad786 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -1209,6 +1209,37 @@ struct vfio_iommu_type1_pasid_request {

#define VFIO_IOMMU_PASID_REQUEST _IO(VFIO_TYPE, VFIO_BASE + 18)

+/**
+ * VFIO_IOMMU_NESTING_OP - _IOW(VFIO_TYPE, VFIO_BASE + 19,
+ * struct vfio_iommu_type1_nesting_op)
+ *
+ * This interface allows user space to utilize the nesting IOMMU
+ * capabilities as reported in VFIO_IOMMU_TYPE1_INFO_CAP_NESTING
+ * cap through VFIO_IOMMU_GET_INFO.
+ *
+ * @data[] types defined for each op:
+ * +=================+===============================================+
+ * | NESTING OP | @data[] |
+ * +=================+===============================================+
+ * | BIND_PGTBL | struct iommu_gpasid_bind_data |
+ * +-----------------+-----------------------------------------------+
+ * | UNBIND_PGTBL | struct iommu_gpasid_bind_data |
+ * +-----------------+-----------------------------------------------+
+ *
+ * returns: 0 on success, -errno on failure.
+ */
+struct vfio_iommu_type1_nesting_op {
+ __u32 argsz;
+ __u32 flags;
+#define VFIO_NESTING_OP_MASK (0xffff) /* lower 16-bits for op */
+ __u8 data[];
+};
+
+#define VFIO_IOMMU_NESTING_OP_BIND_PGTBL (0)
+#define VFIO_IOMMU_NESTING_OP_UNBIND_PGTBL (1)
+
+#define VFIO_IOMMU_NESTING_OP _IO(VFIO_TYPE, VFIO_BASE + 19)
+
/* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */

/*
--
2.7.4