[RFC PATCH v2] iommu/virtio: Use page size bitmap supported by endpoint

From: Bharat Bhushan
Date: Wed Apr 01 2020 - 07:38:19 EST


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 <bbhushan2@xxxxxxxxxxx>
---
drivers/iommu/virtio-iommu.c | 33 +++++++++++++++++++++++++++----
include/uapi/linux/virtio_iommu.h | 7 +++++++
2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index cce329d71fba..c794cb5b7b3e 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 +416,20 @@ 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)
@@ -494,11 +509,13 @@ static int viommu_probe_endpoint(struct viommu_dev *viommu, struct device *dev)
while (type != VIRTIO_IOMMU_PROBE_T_NONE &&
cur < viommu->probe_size) {
len = le16_to_cpu(prop->length) + sizeof(*prop);
-
switch (type) {
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);
}
@@ -607,16 +624,23 @@ static struct iommu_domain *viommu_domain_alloc(unsigned type)
return &vdomain->domain;
}

-static int viommu_domain_finalise(struct viommu_dev *viommu,
+static int viommu_domain_finalise(struct viommu_endpoint *vdev,
struct iommu_domain *domain)
{
int ret;
struct viommu_domain *vdomain = to_viommu_domain(domain);
+ struct viommu_dev *viommu = vdev->viommu;

vdomain->viommu = viommu;
vdomain->map_flags = viommu->map_flags;

- domain->pgsize_bitmap = viommu->pgsize_bitmap;
+ /* Devices in same domain must support same size pages */
+ if ((domain->pgsize_bitmap != viommu->pgsize_bitmap) &&
+ (domain->pgsize_bitmap != vdev->pgsize_bitmap))
+ return -EINVAL;
+
+ domain->pgsize_bitmap = vdev->pgsize_bitmap;
+
domain->geometry = viommu->geometry;

ret = ida_alloc_range(&viommu->domain_ids, viommu->first_domain,
@@ -657,7 +681,7 @@ static int viommu_attach_dev(struct iommu_domain *domain, struct device *dev)
* Properly initialize the domain now that we know which viommu
* owns it.
*/
- ret = viommu_domain_finalise(vdev->viommu, domain);
+ ret = viommu_domain_finalise(vdev, domain);
} else if (vdomain->viommu != vdev->viommu) {
dev_err(dev, "cannot attach to foreign vIOMMU\n");
ret = -EXDEV;
@@ -875,6 +899,7 @@ 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);
fwspec->iommu_priv = vdev;

diff --git a/include/uapi/linux/virtio_iommu.h b/include/uapi/linux/virtio_iommu.h
index 237e36a280cb..dc9d3f40bcd8 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];
+ __u64 pgsize_bitmap;
+};
+
#define VIRTIO_IOMMU_RESV_MEM_T_RESERVED 0
#define VIRTIO_IOMMU_RESV_MEM_T_MSI 1

--
2.17.1