vfio: Simplify capability helper

The vfio_info_add_capability() helper requires the caller to pass a
capability ID, which it then uses to fill in header fields, assuming
hard coded versions.  This makes for an awkward and rigid interface.
The only thing we want this helper to do is allocate sufficient
space in the caps buffer and chain this capability into the list.
Reduce it to that simple task.

Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 96060920a6fea2d9eead2134f313dabd3a003b09..0a7d084da1a2759242be0f7144ad77bc5967df0d 100644 (file)
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -1012,6 +1012,8 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
                        if (!sparse)
                                return -ENOMEM;
 
+                       sparse->header.id = VFIO_REGION_INFO_CAP_SPARSE_MMAP;
+                       sparse->header.version = 1;
                        sparse->nr_areas = nr_areas;
                        cap_type_id = VFIO_REGION_INFO_CAP_SPARSE_MMAP;
                        sparse->areas[0].offset =
@@ -1033,7 +1035,9 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
                        break;
                default:
                        {
-                               struct vfio_region_info_cap_type cap_type;
+                               struct vfio_region_info_cap_type cap_type = {
+                                       .header.id = VFIO_REGION_INFO_CAP_TYPE,
+                                       .header.version = 1 };
 
                                if (info.index >= VFIO_PCI_NUM_REGIONS +
                                                vgpu->vdev.num_regions)
@@ -1050,8 +1054,8 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
                                cap_type.subtype = vgpu->vdev.region[i].subtype;
 
                                ret = vfio_info_add_capability(&caps,
-                                               VFIO_REGION_INFO_CAP_TYPE,
-                                               &cap_type);
+                                                       &cap_type.header,
+                                                       sizeof(cap_type));
                                if (ret)
                                        return ret;
                        }
@@ -1061,8 +1065,9 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
                        switch (cap_type_id) {
                        case VFIO_REGION_INFO_CAP_SPARSE_MMAP:
                                ret = vfio_info_add_capability(&caps,
-                                       VFIO_REGION_INFO_CAP_SPARSE_MMAP,
-                                       sparse);
+                                       &sparse->header, sizeof(*sparse) +
+                                       (sparse->nr_areas *
+                                               sizeof(*sparse->areas)));
                                kfree(sparse);
                                if (ret)
                                        return ret;

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index a98681dca1d3a55a3ea60db8d6856c5a08da1538..de48acd29a84f529e876849c6ba8b6d83d00f818 100644 (file)
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -585,6 +585,8 @@ static int msix_sparse_mmap_cap(struct vfio_pci_device *vdev,
        if (!sparse)
                return -ENOMEM;
 
+       sparse->header.id = VFIO_REGION_INFO_CAP_SPARSE_MMAP;
+       sparse->header.version = 1;
        sparse->nr_areas = nr_areas;
 
        if (vdev->msix_offset & PAGE_MASK) {
@@ -600,8 +602,7 @@ static int msix_sparse_mmap_cap(struct vfio_pci_device *vdev,
                i++;
        }
 
-       ret = vfio_info_add_capability(caps, VFIO_REGION_INFO_CAP_SPARSE_MMAP,
-                                      sparse);
+       ret = vfio_info_add_capability(caps, &sparse->header, size);
        kfree(sparse);
 
        return ret;
@@ -744,7 +745,9 @@ static long vfio_pci_ioctl(void *device_data,
                        break;
                default:
                {
-                       struct vfio_region_info_cap_type cap_type;
+                       struct vfio_region_info_cap_type cap_type = {
+                                       .header.id = VFIO_REGION_INFO_CAP_TYPE,
+                                       .header.version = 1 };
 
                        if (info.index >=
                            VFIO_PCI_NUM_REGIONS + vdev->num_regions)
@@ -759,9 +762,8 @@ static long vfio_pci_ioctl(void *device_data,
                        cap_type.type = vdev->region[i].type;
                        cap_type.subtype = vdev->region[i].subtype;
 
-                       ret = vfio_info_add_capability(&caps,
-                                                     VFIO_REGION_INFO_CAP_TYPE,
-                                                     &cap_type);
+                       ret = vfio_info_add_capability(&caps, &cap_type.header,
+                                                      sizeof(cap_type));
                        if (ret)
                                return ret;
 

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 2bc3705a99bd2f1a670e96c9f1175795b961c922..721f97f8dac1f2c979e846dcd89aa6878e195b59 100644 (file)
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1857,63 +1857,19 @@ void vfio_info_cap_shift(struct vfio_info_cap *caps, size_t offset)
 }
 EXPORT_SYMBOL(vfio_info_cap_shift);
 
-static int sparse_mmap_cap(struct vfio_info_cap *caps, void *cap_type)
+int vfio_info_add_capability(struct vfio_info_cap *caps,
+                            struct vfio_info_cap_header *cap, size_t size)
 {
        struct vfio_info_cap_header *header;
-       struct vfio_region_info_cap_sparse_mmap *sparse_cap, *sparse = cap_type;
-       size_t size;
 
-       size = sizeof(*sparse) + sparse->nr_areas *  sizeof(*sparse->areas);
-       header = vfio_info_cap_add(caps, size,
-                                  VFIO_REGION_INFO_CAP_SPARSE_MMAP, 1);
+       header = vfio_info_cap_add(caps, size, cap->id, cap->version);
        if (IS_ERR(header))
                return PTR_ERR(header);
 
-       sparse_cap = container_of(header,
-                       struct vfio_region_info_cap_sparse_mmap, header);
-       sparse_cap->nr_areas = sparse->nr_areas;
-       memcpy(sparse_cap->areas, sparse->areas,
-              sparse->nr_areas * sizeof(*sparse->areas));
-       return 0;
-}
-
-static int region_type_cap(struct vfio_info_cap *caps, void *cap_type)
-{
-       struct vfio_info_cap_header *header;
-       struct vfio_region_info_cap_type *type_cap, *cap = cap_type;
+       memcpy(header + 1, cap + 1, size - sizeof(*header));
 
-       header = vfio_info_cap_add(caps, sizeof(*cap),
-                                  VFIO_REGION_INFO_CAP_TYPE, 1);
-       if (IS_ERR(header))
-               return PTR_ERR(header);
-
-       type_cap = container_of(header, struct vfio_region_info_cap_type,
-                               header);
-       type_cap->type = cap->type;
-       type_cap->subtype = cap->subtype;
        return 0;
 }
-
-int vfio_info_add_capability(struct vfio_info_cap *caps, int cap_type_id,
-                            void *cap_type)
-{
-       int ret = -EINVAL;
-
-       if (!cap_type)
-               return 0;
-
-       switch (cap_type_id) {
-       case VFIO_REGION_INFO_CAP_SPARSE_MMAP:
-               ret = sparse_mmap_cap(caps, cap_type);
-               break;
-
-       case VFIO_REGION_INFO_CAP_TYPE:
-               ret = region_type_cap(caps, cap_type);
-               break;
-       }
-
-       return ret;
-}
 EXPORT_SYMBOL(vfio_info_add_capability);
 
 int vfio_set_irqs_validate_and_prepare(struct vfio_irq_set *hdr, int num_irqs,

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index a47b985341d12cb685a525c9a5d7179d376cb6a9..66741ab087c12b1d5be26ce4e088f895e594cf42 100644 (file)
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -145,7 +145,8 @@ extern struct vfio_info_cap_header *vfio_info_cap_add(
 extern void vfio_info_cap_shift(struct vfio_info_cap *caps, size_t offset);
 
 extern int vfio_info_add_capability(struct vfio_info_cap *caps,
-                                   int cap_type_id, void *cap_type);
+                                   struct vfio_info_cap_header *cap,
+                                   size_t size);
 
 extern int vfio_set_irqs_validate_and_prepare(struct vfio_irq_set *hdr,
                                              int num_irqs, int max_irq_type,