From 25abc060d282132ea5c945392f900dca0a7e9bbb Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Tue, 4 Aug 2020 19:20:40 +0300 Subject: [PATCH] vhost-vdpa: support IOTLB batching hints This patches extend the vhost IOTLB API to accept batch updating hints form userspace. When userspace wants update the device IOTLB in a batch, it may do: 1) Write vhost_iotlb_msg with VHOST_IOTLB_BATCH_BEGIN flag 2) Perform a batch of IOTLB updating via VHOST_IOTLB_UPDATE/INVALIDATE 3) Write vhost_iotlb_msg with VHOST_IOTLB_BATCH_END flag Vhost-vdpa may decide to batch the IOMMU/IOTLB updating in step 3 when vDPA device support set_map() ops. This is useful for the vDPA device that want to know all the mappings to tweak their own DMA translation logic. For vDPA device that doesn't require set_map(), no behavior changes. This capability is advertised via VHOST_BACKEND_F_IOTLB_BATCH capability. Signed-off-by: Jason Wang Link: https://lore.kernel.org/r/20200804162048.22587-5-eli@mellanox.com Signed-off-by: Michael S. Tsirkin --- drivers/vhost/vdpa.c | 36 ++++++++++++++++++++++++-------- include/uapi/linux/vhost.h | 2 ++ include/uapi/linux/vhost_types.h | 11 ++++++++++ 3 files changed, 40 insertions(+), 9 deletions(-) diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c index 61c17d34cb39..e80db051845d 100644 --- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -27,7 +27,9 @@ #include "vhost.h" enum { - VHOST_VDPA_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) + VHOST_VDPA_BACKEND_FEATURES = + (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) | + (1ULL << VHOST_BACKEND_F_IOTLB_BATCH), }; /* Currently, only network backend w/o multiqueue is supported. */ @@ -48,6 +50,7 @@ struct vhost_vdpa { int virtio_id; int minor; struct eventfd_ctx *config_ctx; + int in_batch; }; static DEFINE_IDA(vhost_vdpa_ida); @@ -124,6 +127,7 @@ static void vhost_vdpa_reset(struct vhost_vdpa *v) struct vdpa_device *vdpa = v->vdpa; vdpa_reset(vdpa); + v->in_batch = 0; } static long vhost_vdpa_get_device_id(struct vhost_vdpa *v, u8 __user *argp) @@ -546,13 +550,15 @@ static int vhost_vdpa_map(struct vhost_vdpa *v, if (r) return r; - if (ops->dma_map) + if (ops->dma_map) { r = ops->dma_map(vdpa, iova, size, pa, perm); - else if (ops->set_map) - r = ops->set_map(vdpa, dev->iotlb); - else + } else if (ops->set_map) { + if (!v->in_batch) + r = ops->set_map(vdpa, dev->iotlb); + } else { r = iommu_map(v->domain, iova, pa, size, perm_to_iommu_flags(perm)); + } return r; } @@ -565,12 +571,14 @@ static void vhost_vdpa_unmap(struct vhost_vdpa *v, u64 iova, u64 size) vhost_vdpa_iotlb_unmap(v, iova, iova + size - 1); - if (ops->dma_map) + if (ops->dma_map) { ops->dma_unmap(vdpa, iova, size); - else if (ops->set_map) - ops->set_map(vdpa, dev->iotlb); - else + } else if (ops->set_map) { + if (!v->in_batch) + ops->set_map(vdpa, dev->iotlb); + } else { iommu_unmap(v->domain, iova, size); + } } static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v, @@ -663,6 +671,8 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev, struct vhost_iotlb_msg *msg) { struct vhost_vdpa *v = container_of(dev, struct vhost_vdpa, vdev); + struct vdpa_device *vdpa = v->vdpa; + const struct vdpa_config_ops *ops = vdpa->config; int r = 0; r = vhost_dev_check_owner(dev); @@ -676,6 +686,14 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev, case VHOST_IOTLB_INVALIDATE: vhost_vdpa_unmap(v, msg->iova, msg->size); break; + case VHOST_IOTLB_BATCH_BEGIN: + v->in_batch = true; + break; + case VHOST_IOTLB_BATCH_END: + if (v->in_batch && ops->set_map) + ops->set_map(vdpa, dev->iotlb); + v->in_batch = false; + break; default: r = -EINVAL; break; diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h index 0c2349612e77..75232185324a 100644 --- a/include/uapi/linux/vhost.h +++ b/include/uapi/linux/vhost.h @@ -91,6 +91,8 @@ /* Use message type V2 */ #define VHOST_BACKEND_F_IOTLB_MSG_V2 0x1 +/* IOTLB can accept batching hints */ +#define VHOST_BACKEND_F_IOTLB_BATCH 0x2 #define VHOST_SET_BACKEND_FEATURES _IOW(VHOST_VIRTIO, 0x25, __u64) #define VHOST_GET_BACKEND_FEATURES _IOR(VHOST_VIRTIO, 0x26, __u64) diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h index 669457ce5c48..9a269a88a6ff 100644 --- a/include/uapi/linux/vhost_types.h +++ b/include/uapi/linux/vhost_types.h @@ -60,6 +60,17 @@ struct vhost_iotlb_msg { #define VHOST_IOTLB_UPDATE 2 #define VHOST_IOTLB_INVALIDATE 3 #define VHOST_IOTLB_ACCESS_FAIL 4 +/* + * VHOST_IOTLB_BATCH_BEGIN and VHOST_IOTLB_BATCH_END allow modifying + * multiple mappings in one go: beginning with + * VHOST_IOTLB_BATCH_BEGIN, followed by any number of + * VHOST_IOTLB_UPDATE messages, and ending with VHOST_IOTLB_BATCH_END. + * When one of these two values is used as the message type, the rest + * of the fields in the message are ignored. There's no guarantee that + * these changes take place automatically in the device. + */ +#define VHOST_IOTLB_BATCH_BEGIN 5 +#define VHOST_IOTLB_BATCH_END 6 __u8 type; };