From 169a126c6e88a99578a309a9021f314b5d532c5f Mon Sep 17 00:00:00 2001 From: Jean-Philippe Brucker Date: Tue, 15 Jan 2019 12:19:59 +0000 Subject: [PATCH] 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 Tested-by: Eric Auger Reviewed-by: Eric Auger Signed-off-by: Jean-Philippe Brucker Signed-off-by: Michael S. Tsirkin --- drivers/iommu/virtio-iommu.c | 115 +++++++++++++++++++++++++++--- include/uapi/linux/virtio_iommu.h | 19 +++++ 2 files changed, 125 insertions(+), 9 deletions(-) diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c index 5e194493a531..4620dd221ffd 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) @@ -503,6 +514,68 @@ out_free: 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) diff --git a/include/uapi/linux/virtio_iommu.h b/include/uapi/linux/virtio_iommu.h index ae6145cf5928..ba1b460c9944 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