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iommu/virtio: Add event queue 

The event queue offers a way for the device to report access faults from
endpoints. It is implemented on virtqueue #1. Whenever the host needs to
signal a fault, it fills one of the buffers offered by the guest and
interrupts it.

Tested-by: Bharat Bhushan <bharat.bhushan@nxp.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Jean-Philippe Brucker 2019-01-15 12:19:59 +00:00 committed by Michael S. Tsirkin
parent 2a5a314874
commit 169a126c6e
2 changed files with 125 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

115
drivers/iommu/virtio-iommu.c
View File

@ -29,7 +29,8 @@
#define MSI_IOVA_LENGTH 0x100000
#define VIOMMU_REQUEST_VQ 0
#define VIOMMU_NR_VQS 1
#define VIOMMU_EVENT_VQ 1
#define VIOMMU_NR_VQS 2
struct viommu_dev {
struct iommu_device iommu;
@ -41,6 +42,7 @@ struct viommu_dev {
struct virtqueue *vqs[VIOMMU_NR_VQS];
spinlock_t request_lock;
struct list_head requests;
void *evts;
/* Device configuration */
struct iommu_domain_geometry geometry;
@ -82,6 +84,15 @@ struct viommu_request {
char buf[];
};
#define VIOMMU_FAULT_RESV_MASK 0xffffff00
struct viommu_event {
union {
u32 head;
struct virtio_iommu_fault fault;
};
};
#define to_viommu_domain(domain) \
container_of(domain, struct viommu_domain, domain)
@ -503,6 +514,68 @@ static int viommu_probe_endpoint(struct viommu_dev *viommu, struct device *dev)
return ret;
}
static int viommu_fault_handler(struct viommu_dev *viommu,
struct virtio_iommu_fault *fault)
{
char *reason_str;
u8 reason = fault->reason;
u32 flags = le32_to_cpu(fault->flags);
u32 endpoint = le32_to_cpu(fault->endpoint);
u64 address = le64_to_cpu(fault->address);
switch (reason) {
case VIRTIO_IOMMU_FAULT_R_DOMAIN:
reason_str = "domain";
break;
case VIRTIO_IOMMU_FAULT_R_MAPPING:
reason_str = "page";
break;
case VIRTIO_IOMMU_FAULT_R_UNKNOWN:
default:
reason_str = "unknown";
break;
}
/* TODO: find EP by ID and report_iommu_fault */
if (flags & VIRTIO_IOMMU_FAULT_F_ADDRESS)
dev_err_ratelimited(viommu->dev, "%s fault from EP %u at %#llx [%s%s%s]\n",
reason_str, endpoint, address,
flags & VIRTIO_IOMMU_FAULT_F_READ ? "R" : "",
flags & VIRTIO_IOMMU_FAULT_F_WRITE ? "W" : "",
flags & VIRTIO_IOMMU_FAULT_F_EXEC ? "X" : "");
else
dev_err_ratelimited(viommu->dev, "%s fault from EP %u\n",
reason_str, endpoint);
return 0;
}
static void viommu_event_handler(struct virtqueue *vq)
{
int ret;
unsigned int len;
struct scatterlist sg[1];
struct viommu_event *evt;
struct viommu_dev *viommu = vq->vdev->priv;
while ((evt = virtqueue_get_buf(vq, &len)) != NULL) {
if (len > sizeof(*evt)) {
dev_err(viommu->dev,
"invalid event buffer (len %u != %zu)\n",
len, sizeof(*evt));
} else if (!(evt->head & VIOMMU_FAULT_RESV_MASK)) {
viommu_fault_handler(viommu, &evt->fault);
}
sg_init_one(sg, evt, sizeof(*evt));
ret = virtqueue_add_inbuf(vq, sg, 1, evt, GFP_ATOMIC);
if (ret)
dev_err(viommu->dev, "could not add event buffer\n");
}
virtqueue_kick(vq);
}
/* IOMMU API */
static struct iommu_domain *viommu_domain_alloc(unsigned type)
@ -886,17 +959,36 @@ static struct iommu_ops viommu_ops = {
static int viommu_init_vqs(struct viommu_dev *viommu)
{
struct virtio_device *vdev = dev_to_virtio(viommu->dev);
const char *name = "request";
void *ret;
const char *names[] = { "request", "event" };
vq_callback_t *callbacks[] = {
NULL, /* No async requests */
viommu_event_handler,
};
ret = virtio_find_single_vq(vdev, NULL, name);
if (IS_ERR(ret)) {
dev_err(viommu->dev, "cannot find VQ\n");
return PTR_ERR(ret);
return virtio_find_vqs(vdev, VIOMMU_NR_VQS, viommu->vqs, callbacks,
names, NULL);
}
static int viommu_fill_evtq(struct viommu_dev *viommu)
{
int i, ret;
struct scatterlist sg[1];
struct viommu_event *evts;
struct virtqueue *vq = viommu->vqs[VIOMMU_EVENT_VQ];
size_t nr_evts = vq->num_free;
viommu->evts = evts = devm_kmalloc_array(viommu->dev, nr_evts,
sizeof(*evts), GFP_KERNEL);
if (!evts)
return -ENOMEM;
for (i = 0; i < nr_evts; i++) {
sg_init_one(sg, &evts[i], sizeof(*evts));
ret = virtqueue_add_inbuf(vq, sg, 1, &evts[i], GFP_KERNEL);
if (ret)
return ret;
}
viommu->vqs[VIOMMU_REQUEST_VQ] = ret;
return 0;
}
@ -964,6 +1056,11 @@ static int viommu_probe(struct virtio_device *vdev)
virtio_device_ready(vdev);
/* Populate the event queue with buffers */
ret = viommu_fill_evtq(viommu);
if (ret)
goto err_free_vqs;
ret = iommu_device_sysfs_add(&viommu->iommu, dev, NULL, "%s",
virtio_bus_name(vdev));
if (ret)

19
include/uapi/linux/virtio_iommu.h
View File

@ -139,4 +139,23 @@ struct virtio_iommu_req_probe {
*/
};
/* Fault types */
#define VIRTIO_IOMMU_FAULT_R_UNKNOWN 0
#define VIRTIO_IOMMU_FAULT_R_DOMAIN 1
#define VIRTIO_IOMMU_FAULT_R_MAPPING 2
#define VIRTIO_IOMMU_FAULT_F_READ (1 << 0)
#define VIRTIO_IOMMU_FAULT_F_WRITE (1 << 1)
#define VIRTIO_IOMMU_FAULT_F_EXEC (1 << 2)
#define VIRTIO_IOMMU_FAULT_F_ADDRESS (1 << 8)
struct virtio_iommu_fault {
__u8 reason;
__u8 reserved[3];
__le32 flags;
__le32 endpoint;
__u8 reserved2[4];
__le64 address;
};
#endif