Hi Jean,
On 11/15/18 5:52 PM, Jean-Philippe Brucker wrote:
> 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.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx>
> ---
> drivers/iommu/virtio-iommu.c | 116 +++++++++++++++++++++++++++---
> include/uapi/linux/virtio_iommu.h | 19 +++++
> 2 files changed, 126 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
> index c547ebd79c43..81c6b72e9c43 100644
> --- a/drivers/iommu/virtio-iommu.c
> +++ b/drivers/iommu/virtio-iommu.c
> @@ -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)
>
> @@ -504,6 +515,69 @@ 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");
> + }
> +
> + if (!virtqueue_kick(vq))
> + dev_err(viommu->dev, "kick failed\n");
There are other occurences of virtqueue_kick where you don't check the
returned value
> +}
> +
> /* IOMMU API */
>
> static struct iommu_domain *viommu_domain_alloc(unsigned type)
> @@ -887,16 +961,35 @@ 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);
> +}
>
> - viommu->vqs[VIOMMU_REQUEST_VQ] = ret;
> +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;
> + }
>
> return 0;
> }
> @@ -965,6 +1058,11 @@ 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)
> diff --git a/include/uapi/linux/virtio_iommu.h b/include/uapi/linux/virtio_iommu.h
> index cde2a3409caa..fed2ba5b47ab 100644
> --- a/include/uapi/linux/virtio_iommu.h
> +++ b/include/uapi/linux/virtio_iommu.h
> @@ -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
>
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
Thanks
Eric
