[PATCH v5] iommu/virtio: Use page size bitmap supported by endpoint

[Bharat Bhushan]

Different endpoint can support different page size, probe
endpoint if it supports specific page size otherwise use
global page sizes.

Signed-off-by: Bharat Bhushan <bbhush...@marvell.com>
---
v4->v5:
 - Rebase to Linux v5.7-rc4

v3->v4:
 - Fix whitespace error

v2->v3:
 - Fixed error return for incompatible endpoint
 - __u64 changed to __le64 in header file

 drivers/iommu/virtio-iommu.c      | 48 ++++++++++++++++++++++++++++---
 include/uapi/linux/virtio_iommu.h |  7 +++++
 2 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index d5cac4f46ca5..9513d2ab819e 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -78,6 +78,7 @@ struct viommu_endpoint {
        struct viommu_dev               *viommu;
        struct viommu_domain            *vdomain;
        struct list_head                resv_regions;
+       u64                             pgsize_bitmap;
 };
 
 struct viommu_request {
@@ -415,6 +416,19 @@ static int viommu_replay_mappings(struct viommu_domain 
*vdomain)
        return ret;
 }
 
+static int viommu_set_pgsize_bitmap(struct viommu_endpoint *vdev,
+                                   struct virtio_iommu_probe_pgsize_mask *mask,
+                                   size_t len)
+{
+       u64 pgsize_bitmap = le64_to_cpu(mask->pgsize_bitmap);
+
+       if (len < sizeof(*mask))
+               return -EINVAL;
+
+       vdev->pgsize_bitmap = pgsize_bitmap;
+       return 0;
+}
+
 static int viommu_add_resv_mem(struct viommu_endpoint *vdev,
                               struct virtio_iommu_probe_resv_mem *mem,
                               size_t len)
@@ -499,6 +513,9 @@ static int viommu_probe_endpoint(struct viommu_dev *viommu, 
struct device *dev)
                case VIRTIO_IOMMU_PROBE_T_RESV_MEM:
                        ret = viommu_add_resv_mem(vdev, (void *)prop, len);
                        break;
+               case VIRTIO_IOMMU_PROBE_T_PAGE_SIZE_MASK:
+                       ret = viommu_set_pgsize_bitmap(vdev, (void *)prop, len);
+                       break;
                default:
                        dev_err(dev, "unknown viommu prop 0x%x\n", type);
                }
@@ -630,7 +647,7 @@ static int viommu_domain_finalise(struct viommu_endpoint 
*vdev,
 
        vdomain->id             = (unsigned int)ret;
 
-       domain->pgsize_bitmap   = viommu->pgsize_bitmap;
+       domain->pgsize_bitmap   = vdev->pgsize_bitmap;
        domain->geometry        = viommu->geometry;
 
        vdomain->map_flags      = viommu->map_flags;
@@ -654,6 +671,29 @@ static void viommu_domain_free(struct iommu_domain *domain)
        kfree(vdomain);
 }
 
+/*
+ * Check whether the endpoint's capabilities are compatible with other
+ * endpoints in the domain. Report any inconsistency.
+ */
+static bool viommu_endpoint_is_compatible(struct viommu_endpoint *vdev,
+                                         struct viommu_domain *vdomain)
+{
+       struct device *dev = vdev->dev;
+
+       if (vdomain->viommu != vdev->viommu) {
+               dev_err(dev, "cannot attach to foreign vIOMMU\n");
+               return false;
+       }
+
+       if (vdomain->domain.pgsize_bitmap != vdev->pgsize_bitmap) {
+               dev_err(dev, "incompatible domain bitmap 0x%lx != 0x%llx\n",
+                       vdomain->domain.pgsize_bitmap, vdev->pgsize_bitmap);
+               return false;
+       }
+
+       return true;
+}
+
 static int viommu_attach_dev(struct iommu_domain *domain, struct device *dev)
 {
        int i;
@@ -670,9 +710,8 @@ static int viommu_attach_dev(struct iommu_domain *domain, 
struct device *dev)
                 * owns it.
                 */
                ret = viommu_domain_finalise(vdev, domain);
-       } else if (vdomain->viommu != vdev->viommu) {
-               dev_err(dev, "cannot attach to foreign vIOMMU\n");
-               ret = -EXDEV;
+       } else if (!viommu_endpoint_is_compatible(vdev, vdomain)) {
+               ret = -EINVAL;
        }
        mutex_unlock(&vdomain->mutex);
 
@@ -886,6 +925,7 @@ static int viommu_add_device(struct device *dev)
 
        vdev->dev = dev;
        vdev->viommu = viommu;
+       vdev->pgsize_bitmap = viommu->pgsize_bitmap;
        INIT_LIST_HEAD(&vdev->resv_regions);
        dev_iommu_priv_set(dev, vdev);
 
diff --git a/include/uapi/linux/virtio_iommu.h 
b/include/uapi/linux/virtio_iommu.h
index 48e3c29223b5..2cced7accc99 100644
--- a/include/uapi/linux/virtio_iommu.h
+++ b/include/uapi/linux/virtio_iommu.h
@@ -111,6 +111,7 @@ struct virtio_iommu_req_unmap {
 
 #define VIRTIO_IOMMU_PROBE_T_NONE              0
 #define VIRTIO_IOMMU_PROBE_T_RESV_MEM          1
+#define VIRTIO_IOMMU_PROBE_T_PAGE_SIZE_MASK    2
 
 #define VIRTIO_IOMMU_PROBE_T_MASK              0xfff
 
@@ -119,6 +120,12 @@ struct virtio_iommu_probe_property {
        __le16                                  length;
 };
 
+struct virtio_iommu_probe_pgsize_mask {
+       struct virtio_iommu_probe_property      head;
+       __u8                                    reserved[4];
+       __le64                                  pgsize_bitmap;
+};
+
 #define VIRTIO_IOMMU_RESV_MEM_T_RESERVED       0
 #define VIRTIO_IOMMU_RESV_MEM_T_MSI            1
 
-- 
2.17.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu