When the device offers the probe feature, send a probe request for each
device managed by the IOMMU. Extract RESV_MEM information. When we
encounter a MSI doorbell region, set it up as a IOMMU_RESV_MSI region.
This will tell other subsystems that there is no need to map the MSI
doorbell in the virtio-iommu, because MSIs bypass it.
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx>
---
drivers/iommu/virtio-iommu.c | 163 ++++++++++++++++++++++++++++++++++++--
include/uapi/linux/virtio_iommu.h | 37 +++++++++
2 files changed, 193 insertions(+), 7 deletions(-)
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index a9c9245e8ba2..3ac4b38eaf19 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -45,6 +45,7 @@ struct viommu_dev {
struct iommu_domain_geometry geometry;
u64 pgsize_bitmap;
u8 domain_bits;
+ u32 probe_size;
};
struct viommu_mapping {
@@ -72,6 +73,7 @@ struct viommu_domain {
struct viommu_endpoint {
struct viommu_dev *viommu;
struct viommu_domain *vdomain;
+ struct list_head resv_regions;
};
struct viommu_request {
@@ -140,6 +142,10 @@ static int viommu_get_req_size(struct viommu_dev *viommu,
case VIRTIO_IOMMU_T_UNMAP:
size = sizeof(r->unmap);
break;
+ case VIRTIO_IOMMU_T_PROBE:
+ *bottom += viommu->probe_size;
+ size = sizeof(r->probe) + *bottom;
+ break;
default:
return -EINVAL;
}
@@ -448,6 +454,105 @@ static int viommu_replay_mappings(struct viommu_domain *vdomain)
return ret;
}
+static int viommu_add_resv_mem(struct viommu_endpoint *vdev,
+ struct virtio_iommu_probe_resv_mem *mem,
+ size_t len)
+{
+ struct iommu_resv_region *region = NULL;
+ unsigned long prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
+
+ u64 addr = le64_to_cpu(mem->addr);
+ u64 size = le64_to_cpu(mem->size);
+
+ if (len < sizeof(*mem))
+ return -EINVAL;
+
+ switch (mem->subtype) {
+ case VIRTIO_IOMMU_RESV_MEM_T_MSI:
+ region = iommu_alloc_resv_region(addr, size, prot,
+ IOMMU_RESV_MSI);
+ break;
+ case VIRTIO_IOMMU_RESV_MEM_T_RESERVED:
+ default:
+ region = iommu_alloc_resv_region(addr, size, 0,
+ IOMMU_RESV_RESERVED);
+ break;
+ }
+
+ list_add(&vdev->resv_regions, ®ion->list);
+
+ /*
+ * Treat unknown subtype as RESERVED, but urge users to update their
+ * driver.
+ */
+ if (mem->subtype != VIRTIO_IOMMU_RESV_MEM_T_RESERVED &&
+ mem->subtype != VIRTIO_IOMMU_RESV_MEM_T_MSI)
+ pr_warn("unknown resv mem subtype 0x%x\n", mem->subtype);
+
+ return 0;
+}
+
+static int viommu_probe_endpoint(struct viommu_dev *viommu, struct device *dev)
+{
+ int ret;
+ u16 type, len;
+ size_t cur = 0;
+ struct virtio_iommu_req_probe *probe;
+ struct virtio_iommu_probe_property *prop;
+ struct iommu_fwspec *fwspec = dev->iommu_fwspec;
+ struct viommu_endpoint *vdev = fwspec->iommu_priv;
+
+ if (!fwspec->num_ids)
+ /* Trouble ahead. */
+ return -EINVAL;
+
+ probe = kzalloc(sizeof(*probe) + viommu->probe_size +
+ sizeof(struct virtio_iommu_req_tail), GFP_KERNEL);
+ if (!probe)
+ return -ENOMEM;
+
+ probe->head.type = VIRTIO_IOMMU_T_PROBE;
+ /*
+ * For now, assume that properties of an endpoint that outputs multiple
+ * IDs are consistent. Only probe the first one.
+ */
+ probe->endpoint = cpu_to_le32(fwspec->ids[0]);
+
+ ret = viommu_send_req_sync(viommu, probe);
+ if (ret)
+ goto out_free;
+
+ prop = (void *)probe->properties;
+ type = le16_to_cpu(prop->type) & VIRTIO_IOMMU_PROBE_T_MASK;
+
+ while (type != VIRTIO_IOMMU_PROBE_T_NONE &&
+ cur < viommu->probe_size) {
+ len = le16_to_cpu(prop->length);
+
+ switch (type) {
+ case VIRTIO_IOMMU_PROBE_T_RESV_MEM:
+ ret = viommu_add_resv_mem(vdev, (void *)prop->value, len);
+ break;
+ default:
+ dev_dbg(dev, "unknown viommu prop 0x%x\n", type);
+ }
+
+ if (ret)
+ dev_err(dev, "failed to parse viommu prop 0x%x\n", type);
+
+ cur += sizeof(*prop) + len;
+ if (cur >= viommu->probe_size)
+ break;
+
+ prop = (void *)probe->properties + cur;
+ type = le16_to_cpu(prop->type) & VIRTIO_IOMMU_PROBE_T_MASK;
+ }
+
+out_free:
+ kfree(probe);
+ return ret;
+}
+
/* IOMMU API */
static bool viommu_capable(enum iommu_cap cap)
@@ -703,6 +808,7 @@ static struct viommu_dev *viommu_get_by_fwnode(struct fwnode_handle *fwnode)
static int viommu_add_device(struct device *dev)
{
+ int ret;
struct iommu_group *group;
struct viommu_endpoint *vdev;
struct viommu_dev *viommu = NULL;
@@ -720,8 +826,16 @@ static int viommu_add_device(struct device *dev)
return -ENOMEM;
vdev->viommu = viommu;
+ INIT_LIST_HEAD(&vdev->resv_regions);
fwspec->iommu_priv = vdev;
+ if (viommu->probe_size) {
+ /* Get additional information for this endpoint */
+ ret = viommu_probe_endpoint(viommu, dev);
+ if (ret)
+ return ret;
+ }
+
/*
* Last step creates a default domain and attaches to it. Everything
* must be ready.
@@ -735,7 +849,19 @@ static int viommu_add_device(struct device *dev)
static void viommu_remove_device(struct device *dev)
{
- kfree(dev->iommu_fwspec->iommu_priv);
+ struct viommu_endpoint *vdev;
+ struct iommu_resv_region *entry, *next;
+ struct iommu_fwspec *fwspec = dev->iommu_fwspec;
+
+ if (!fwspec || fwspec->ops != &viommu_ops)
+ return;
+
+ vdev = fwspec->iommu_priv;
+
+ list_for_each_entry_safe(entry, next, &vdev->resv_regions, list)
+ kfree(entry);
+
+ kfree(vdev);
}
static struct iommu_group *viommu_device_group(struct device *dev)
@@ -753,15 +879,33 @@ static int viommu_of_xlate(struct device *dev, struct of_phandle_args *args)
static void viommu_get_resv_regions(struct device *dev, struct list_head *head)
{
- struct iommu_resv_region *region;
+ struct iommu_resv_region *entry, *new_entry, *msi = NULL;
+ struct viommu_endpoint *vdev = dev->iommu_fwspec->iommu_priv;
int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
- region = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH, prot,
- IOMMU_RESV_SW_MSI);
- if (!region)
- return;
+ list_for_each_entry(entry, &vdev->resv_regions, list) {
+ /*
+ * If the device registered a bypass MSI windows, use it.
+ * Otherwise add a software-mapped region
+ */
+ if (entry->type == IOMMU_RESV_MSI)
+ msi = entry;
+
+ new_entry = kmemdup(entry, sizeof(*entry), GFP_KERNEL);
+ if (!new_entry)
+ return;
+ list_add_tail(&new_entry->list, head);
+ }
+
+ if (!msi) {
+ msi = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH,
+ prot, IOMMU_RESV_SW_MSI);
+ if (!msi)
+ return;
+
+ list_add_tail(&msi->list, head);
+ }
- list_add_tail(®ion->list, head);
iommu_dma_get_resv_regions(dev, head);
}
@@ -852,6 +996,10 @@ static int viommu_probe(struct virtio_device *vdev)
struct virtio_iommu_config, domain_bits,
&viommu->domain_bits);
+ virtio_cread_feature(vdev, VIRTIO_IOMMU_F_PROBE,
+ struct virtio_iommu_config, probe_size,
+ &viommu->probe_size);
+
viommu->geometry = (struct iommu_domain_geometry) {
.aperture_start = input_start,
.aperture_end = input_end,
@@ -933,6 +1081,7 @@ static unsigned int features[] = {
VIRTIO_IOMMU_F_MAP_UNMAP,
VIRTIO_IOMMU_F_DOMAIN_BITS,
VIRTIO_IOMMU_F_INPUT_RANGE,
+ VIRTIO_IOMMU_F_PROBE,
};
static struct virtio_device_id id_table[] = {
diff --git a/include/uapi/linux/virtio_iommu.h b/include/uapi/linux/virtio_iommu.h
index 0de9b44db14d..2335d9ed4676 100644
--- a/include/uapi/linux/virtio_iommu.h
+++ b/include/uapi/linux/virtio_iommu.h
@@ -15,6 +15,7 @@
#define VIRTIO_IOMMU_F_DOMAIN_BITS 1
#define VIRTIO_IOMMU_F_MAP_UNMAP 2
#define VIRTIO_IOMMU_F_BYPASS 3
+#define VIRTIO_IOMMU_F_PROBE 4
struct virtio_iommu_config {
/* Supported page sizes */
@@ -26,6 +27,9 @@ struct virtio_iommu_config {
} input_range;
/* Max domain ID size */
__u8 domain_bits;
+ __u8 padding[3];
+ /* Probe buffer size */
+ __u32 probe_size;
} __packed;
/* Request types */
@@ -33,6 +37,7 @@ struct virtio_iommu_config {
#define VIRTIO_IOMMU_T_DETACH 0x02
#define VIRTIO_IOMMU_T_MAP 0x03
#define VIRTIO_IOMMU_T_UNMAP 0x04
+#define VIRTIO_IOMMU_T_PROBE 0x05
/* Status types */
#define VIRTIO_IOMMU_S_OK 0x00
@@ -104,6 +109,37 @@ struct virtio_iommu_req_unmap {
struct virtio_iommu_req_tail tail;
} __packed;
+#define VIRTIO_IOMMU_RESV_MEM_T_RESERVED 0
+#define VIRTIO_IOMMU_RESV_MEM_T_MSI 1
+
+struct virtio_iommu_probe_resv_mem {
+ __u8 subtype;
+ __u8 reserved[3];
+ __le64 addr;
+ __le64 size;
+} __packed;
+
+#define VIRTIO_IOMMU_PROBE_T_NONE 0
+#define VIRTIO_IOMMU_PROBE_T_RESV_MEM 1
+
+#define VIRTIO_IOMMU_PROBE_T_MASK 0xfff
+
+struct virtio_iommu_probe_property {
+ __le16 type;
+ __le16 length;
+ __u8 value[];
+} __packed;
+
+struct virtio_iommu_req_probe {
+ struct virtio_iommu_req_head head;
+ __le32 endpoint;
+ __u8 reserved[64];
+
+ __u8 properties[];
+
+ /* Tail follows the variable-length properties array (no padding) */
+} __packed;
+
union virtio_iommu_req {
struct virtio_iommu_req_head head;
@@ -111,6 +147,7 @@ union virtio_iommu_req {
struct virtio_iommu_req_detach detach;
struct virtio_iommu_req_map map;
struct virtio_iommu_req_unmap unmap;
+ struct virtio_iommu_req_probe probe;
};
#endif
--
2.16.1
