| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Tiwei Bie | 6122 | 60.81% | 12 | 13.48% |
| Rusty Russell | 1441 | 14.31% | 24 | 26.97% |
| Andrew Lutomirski | 1222 | 12.14% | 4 | 4.49% |
| Michael S. Tsirkin | 638 | 6.34% | 16 | 17.98% |
| Mark McLoughlin | 108 | 1.07% | 1 | 1.12% |
| Shirley Ma | 106 | 1.05% | 1 | 1.12% |
| Venkatesh Srinivas | 101 | 1.00% | 1 | 1.12% |
| Cornelia Huck | 67 | 0.67% | 2 | 2.25% |
| Joerg Roedel | 40 | 0.40% | 1 | 1.12% |
| Rick Jones | 33 | 0.33% | 1 | 1.12% |
| Heinz Graalfs | 32 | 0.32% | 2 | 2.25% |
| Ladi Prosek | 29 | 0.29% | 1 | 1.12% |
| Richard W.M. Jones | 18 | 0.18% | 1 | 1.12% |
| Tetsuo Handa | 14 | 0.14% | 1 | 1.12% |
| Jiang Biao | 11 | 0.11% | 1 | 1.12% |
| Amit Shah | 10 | 0.10% | 2 | 2.25% |
| Suman Anna | 9 | 0.09% | 1 | 1.12% |
| Matthias Lange | 9 | 0.09% | 1 | 1.12% |
| Wei Yongjun | 9 | 0.09% | 1 | 1.12% |
| Marvin Liu | 8 | 0.08% | 1 | 1.12% |
| Gonglei (Arei) | 8 | 0.08% | 1 | 1.12% |
| Will Deacon | 6 | 0.06% | 1 | 1.12% |
| Yue haibing | 5 | 0.05% | 1 | 1.12% |
| Roel Kluin | 4 | 0.04% | 1 | 1.12% |
| Jason (Hui) Wang | 3 | 0.03% | 2 | 2.25% |
| Paul Gortmaker | 3 | 0.03% | 1 | 1.12% |
| Tejun Heo | 3 | 0.03% | 1 | 1.12% |
| Kees Cook | 2 | 0.02% | 1 | 1.12% |
| Halil Pasic | 2 | 0.02% | 1 | 1.12% |
| Thomas Gleixner | 2 | 0.02% | 1 | 1.12% |
| Baoyou Xie | 1 | 0.01% | 1 | 1.12% |
| Anthony Liguori | 1 | 0.01% | 1 | 1.12% |
| Joel Stanley | 1 | 0.01% | 1 | 1.12% |
| Total | 10068 | 89 |
// SPDX-License-Identifier: GPL-2.0-or-later /* Virtio ring implementation. * * Copyright 2007 Rusty Russell IBM Corporation */ #include <linux/virtio.h> #include <linux/virtio_ring.h> #include <linux/virtio_config.h> #include <linux/device.h> #include <linux/slab.h> #include <linux/module.h> #include <linux/hrtimer.h> #include <linux/dma-mapping.h> #include <xen/xen.h> #ifdef DEBUG /* For development, we want to crash whenever the ring is screwed. */ #define BAD_RING(_vq, fmt, args...) \ do { \ dev_err(&(_vq)->vq.vdev->dev, \ "%s:"fmt, (_vq)->vq.name, ##args); \ BUG(); \ } while (0) /* Caller is supposed to guarantee no reentry. */ #define START_USE(_vq) \ do { \ if ((_vq)->in_use) \ panic("%s:in_use = %i\n", \ (_vq)->vq.name, (_vq)->in_use); \ (_vq)->in_use = __LINE__; \ } while (0) #define END_USE(_vq) \ do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; } while(0) #define LAST_ADD_TIME_UPDATE(_vq) \ do { \ ktime_t now = ktime_get(); \ \ /* No kick or get, with .1 second between? Warn. */ \ if ((_vq)->last_add_time_valid) \ WARN_ON(ktime_to_ms(ktime_sub(now, \ (_vq)->last_add_time)) > 100); \ (_vq)->last_add_time = now; \ (_vq)->last_add_time_valid = true; \ } while (0) #define LAST_ADD_TIME_CHECK(_vq) \ do { \ if ((_vq)->last_add_time_valid) { \ WARN_ON(ktime_to_ms(ktime_sub(ktime_get(), \ (_vq)->last_add_time)) > 100); \ } \ } while (0) #define LAST_ADD_TIME_INVALID(_vq) \ ((_vq)->last_add_time_valid = false) #else #define BAD_RING(_vq, fmt, args...) \ do { \ dev_err(&_vq->vq.vdev->dev, \ "%s:"fmt, (_vq)->vq.name, ##args); \ (_vq)->broken = true; \ } while (0) #define START_USE(vq) #define END_USE(vq) #define LAST_ADD_TIME_UPDATE(vq) #define LAST_ADD_TIME_CHECK(vq) #define LAST_ADD_TIME_INVALID(vq) #endif struct vring_desc_state_split { void *data; /* Data for callback. */ struct vring_desc *indir_desc; /* Indirect descriptor, if any. */ }; struct vring_desc_state_packed { void *data; /* Data for callback. */ struct vring_packed_desc *indir_desc; /* Indirect descriptor, if any. */ u16 num; /* Descriptor list length. */ u16 next; /* The next desc state in a list. */ u16 last; /* The last desc state in a list. */ }; struct vring_desc_extra_packed { dma_addr_t addr; /* Buffer DMA addr. */ u32 len; /* Buffer length. */ u16 flags; /* Descriptor flags. */ }; struct vring_virtqueue { struct virtqueue vq; /* Is this a packed ring? */ bool packed_ring; /* Is DMA API used? */ bool use_dma_api; /* Can we use weak barriers? */ bool weak_barriers; /* Other side has made a mess, don't try any more. */ bool broken; /* Host supports indirect buffers */ bool indirect; /* Host publishes avail event idx */ bool event; /* Head of free buffer list. */ unsigned int free_head; /* Number we've added since last sync. */ unsigned int num_added; /* Last used index we've seen. */ u16 last_used_idx; union { /* Available for split ring */ struct { /* Actual memory layout for this queue. */ struct vring vring; /* Last written value to avail->flags */ u16 avail_flags_shadow; /* * Last written value to avail->idx in * guest byte order. */ u16 avail_idx_shadow; /* Per-descriptor state. */ struct vring_desc_state_split *desc_state; /* DMA address and size information */ dma_addr_t queue_dma_addr; size_t queue_size_in_bytes; } split; /* Available for packed ring */ struct { /* Actual memory layout for this queue. */ struct { unsigned int num; struct vring_packed_desc *desc; struct vring_packed_desc_event *driver; struct vring_packed_desc_event *device; } vring; /* Driver ring wrap counter. */ bool avail_wrap_counter; /* Device ring wrap counter. */ bool used_wrap_counter; /* Avail used flags. */ u16 avail_used_flags; /* Index of the next avail descriptor. */ u16 next_avail_idx; /* * Last written value to driver->flags in * guest byte order. */ u16 event_flags_shadow; /* Per-descriptor state. */ struct vring_desc_state_packed *desc_state; struct vring_desc_extra_packed *desc_extra; /* DMA address and size information */ dma_addr_t ring_dma_addr; dma_addr_t driver_event_dma_addr; dma_addr_t device_event_dma_addr; size_t ring_size_in_bytes; size_t event_size_in_bytes; } packed; }; /* How to notify other side. FIXME: commonalize hcalls! */ bool (*notify)(struct virtqueue *vq); /* DMA, allocation, and size information */ bool we_own_ring; #ifdef DEBUG /* They're supposed to lock for us. */ unsigned int in_use; /* Figure out if their kicks are too delayed. */ bool last_add_time_valid; ktime_t last_add_time; #endif }; /* * Helpers. */ #define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq) static inline bool virtqueue_use_indirect(struct virtqueue *_vq, unsigned int total_sg) { struct vring_virtqueue *vq = to_vvq(_vq); /* * If the host supports indirect descriptor tables, and we have multiple * buffers, then go indirect. FIXME: tune this threshold */ return (vq->indirect && total_sg > 1 && vq->vq.num_free); } /* * Modern virtio devices have feature bits to specify whether they need a * quirk and bypass the IOMMU. If not there, just use the DMA API. * * If there, the interaction between virtio and DMA API is messy. * * On most systems with virtio, physical addresses match bus addresses, * and it doesn't particularly matter whether we use the DMA API. * * On some systems, including Xen and any system with a physical device * that speaks virtio behind a physical IOMMU, we must use the DMA API * for virtio DMA to work at all. * * On other systems, including SPARC and PPC64, virtio-pci devices are * enumerated as though they are behind an IOMMU, but the virtio host * ignores the IOMMU, so we must either pretend that the IOMMU isn't * there or somehow map everything as the identity. * * For the time being, we preserve historic behavior and bypass the DMA * API. * * TODO: install a per-device DMA ops structure that does the right thing * taking into account all the above quirks, and use the DMA API * unconditionally on data path. */ static bool vring_use_dma_api(struct virtio_device *vdev) { if (!virtio_has_iommu_quirk(vdev)) return true; /* Otherwise, we are left to guess. */ /* * In theory, it's possible to have a buggy QEMU-supposed * emulated Q35 IOMMU and Xen enabled at the same time. On * such a configuration, virtio has never worked and will * not work without an even larger kludge. Instead, enable * the DMA API if we're a Xen guest, which at least allows * all of the sensible Xen configurations to work correctly. */ if (xen_domain()) return true; return false; } size_t virtio_max_dma_size(struct virtio_device *vdev) { size_t max_segment_size = SIZE_MAX; if (vring_use_dma_api(vdev)) max_segment_size = dma_max_mapping_size(&vdev->dev); return max_segment_size; } EXPORT_SYMBOL_GPL(virtio_max_dma_size); static void *vring_alloc_queue(struct virtio_device *vdev, size_t size, dma_addr_t *dma_handle, gfp_t flag) { if (vring_use_dma_api(vdev)) { return dma_alloc_coherent(vdev->dev.parent, size, dma_handle, flag); } else { void *queue = alloc_pages_exact(PAGE_ALIGN(size), flag); if (queue) { phys_addr_t phys_addr = virt_to_phys(queue); *dma_handle = (dma_addr_t)phys_addr; /* * Sanity check: make sure we dind't truncate * the address. The only arches I can find that * have 64-bit phys_addr_t but 32-bit dma_addr_t * are certain non-highmem MIPS and x86 * configurations, but these configurations * should never allocate physical pages above 32 * bits, so this is fine. Just in case, throw a * warning and abort if we end up with an * unrepresentable address. */ if (WARN_ON_ONCE(*dma_handle != phys_addr)) { free_pages_exact(queue, PAGE_ALIGN(size)); return NULL; } } return queue; } } static void vring_free_queue(struct virtio_device *vdev, size_t size, void *queue, dma_addr_t dma_handle) { if (vring_use_dma_api(vdev)) dma_free_coherent(vdev->dev.parent, size, queue, dma_handle); else free_pages_exact(queue, PAGE_ALIGN(size)); } /* * The DMA ops on various arches are rather gnarly right now, and * making all of the arch DMA ops work on the vring device itself * is a mess. For now, we use the parent device for DMA ops. */ static inline struct device *vring_dma_dev(const struct vring_virtqueue *vq) { return vq->vq.vdev->dev.parent; } /* Map one sg entry. */ static dma_addr_t vring_map_one_sg(const struct vring_virtqueue *vq, struct scatterlist *sg, enum dma_data_direction direction) { if (!vq->use_dma_api) return (dma_addr_t)sg_phys(sg); /* * We can't use dma_map_sg, because we don't use scatterlists in * the way it expects (we don't guarantee that the scatterlist * will exist for the lifetime of the mapping). */ return dma_map_page(vring_dma_dev(vq), sg_page(sg), sg->offset, sg->length, direction); } static dma_addr_t vring_map_single(const struct vring_virtqueue *vq, void *cpu_addr, size_t size, enum dma_data_direction direction) { if (!vq->use_dma_api) return (dma_addr_t)virt_to_phys(cpu_addr); return dma_map_single(vring_dma_dev(vq), cpu_addr, size, direction); } static int vring_mapping_error(const struct vring_virtqueue *vq, dma_addr_t addr) { if (!vq->use_dma_api) return 0; return dma_mapping_error(vring_dma_dev(vq), addr); } /* * Split ring specific functions - *_split(). */ static void vring_unmap_one_split(const struct vring_virtqueue *vq, struct vring_desc *desc) { u16 flags; if (!vq->use_dma_api) return; flags = virtio16_to_cpu(vq->vq.vdev, desc->flags); if (flags & VRING_DESC_F_INDIRECT) { dma_unmap_single(vring_dma_dev(vq), virtio64_to_cpu(vq->vq.vdev, desc->addr), virtio32_to_cpu(vq->vq.vdev, desc->len), (flags & VRING_DESC_F_WRITE) ? DMA_FROM_DEVICE : DMA_TO_DEVICE); } else { dma_unmap_page(vring_dma_dev(vq), virtio64_to_cpu(vq->vq.vdev, desc->addr), virtio32_to_cpu(vq->vq.vdev, desc->len), (flags & VRING_DESC_F_WRITE) ? DMA_FROM_DEVICE : DMA_TO_DEVICE); } } static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq, unsigned int total_sg, gfp_t gfp) { struct vring_desc *desc; unsigned int i; /* * We require lowmem mappings for the descriptors because * otherwise virt_to_phys will give us bogus addresses in the * virtqueue. */ gfp &= ~__GFP_HIGHMEM; desc = kmalloc_array(total_sg, sizeof(struct vring_desc), gfp); if (!desc) return NULL; for (i = 0; i < total_sg; i++) desc[i].next = cpu_to_virtio16(_vq->vdev, i + 1); return desc; } static inline int virtqueue_add_split(struct virtqueue *_vq, struct scatterlist *sgs[], unsigned int total_sg, unsigned int out_sgs, unsigned int in_sgs, void *data, void *ctx, gfp_t gfp) { struct vring_virtqueue *vq = to_vvq(_vq); struct scatterlist *sg; struct vring_desc *desc; unsigned int i, n, avail, descs_used, uninitialized_var(prev), err_idx; int head; bool indirect; START_USE(vq); BUG_ON(data == NULL); BUG_ON(ctx && vq->indirect); if (unlikely(vq->broken)) { END_USE(vq); return -EIO; } LAST_ADD_TIME_UPDATE(vq); BUG_ON(total_sg == 0); head = vq->free_head; if (virtqueue_use_indirect(_vq, total_sg)) desc = alloc_indirect_split(_vq, total_sg, gfp); else { desc = NULL; WARN_ON_ONCE(total_sg > vq->split.vring.num && !vq->indirect); } if (desc) { /* Use a single buffer which doesn't continue */ indirect = true; /* Set up rest to use this indirect table. */ i = 0; descs_used = 1; } else { indirect = false; desc = vq->split.vring.desc; i = head; descs_used = total_sg; } if (vq->vq.num_free < descs_used) { pr_debug("Can't add buf len %i - avail = %i\n", descs_used, vq->vq.num_free); /* FIXME: for historical reasons, we force a notify here if * there are outgoing parts to the buffer. Presumably the * host should service the ring ASAP. */ if (out_sgs) vq->notify(&vq->vq); if (indirect) kfree(desc); END_USE(vq); return -ENOSPC; } for (n = 0; n < out_sgs; n++) { for (sg = sgs[n]; sg; sg = sg_next(sg)) { dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE); if (vring_mapping_error(vq, addr)) goto unmap_release; desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT); desc[i].addr = cpu_to_virtio64(_vq->vdev, addr); desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length); prev = i; i = virtio16_to_cpu(_vq->vdev, desc[i].next); } } for (; n < (out_sgs + in_sgs); n++) { for (sg = sgs[n]; sg; sg = sg_next(sg)) { dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_FROM_DEVICE); if (vring_mapping_error(vq, addr)) goto unmap_release; desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT | VRING_DESC_F_WRITE); desc[i].addr = cpu_to_virtio64(_vq->vdev, addr); desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length); prev = i; i = virtio16_to_cpu(_vq->vdev, desc[i].next); } } /* Last one doesn't continue. */ desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT); if (indirect) { /* Now that the indirect table is filled in, map it. */ dma_addr_t addr = vring_map_single( vq, desc, total_sg * sizeof(struct vring_desc), DMA_TO_DEVICE); if (vring_mapping_error(vq, addr)) goto unmap_release; vq->split.vring.desc[head].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_INDIRECT); vq->split.vring.desc[head].addr = cpu_to_virtio64(_vq->vdev, addr); vq->split.vring.desc[head].len = cpu_to_virtio32(_vq->vdev, total_sg * sizeof(struct vring_desc)); } /* We're using some buffers from the free list. */ vq->vq.num_free -= descs_used; /* Update free pointer */ if (indirect) vq->free_head = virtio16_to_cpu(_vq->vdev, vq->split.vring.desc[head].next); else vq->free_head = i; /* Store token and indirect buffer state. */ vq->split.desc_state[head].data = data; if (indirect) vq->split.desc_state[head].indir_desc = desc; else vq->split.desc_state[head].indir_desc = ctx; /* Put entry in available array (but don't update avail->idx until they * do sync). */ avail = vq->split.avail_idx_shadow & (vq->split.vring.num - 1); vq->split.vring.avail->ring[avail] = cpu_to_virtio16(_vq->vdev, head); /* Descriptors and available array need to be set before we expose the * new available array entries. */ virtio_wmb(vq->weak_barriers); vq->split.avail_idx_shadow++; vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev, vq->split.avail_idx_shadow); vq->num_added++; pr_debug("Added buffer head %i to %p\n", head, vq); END_USE(vq); /* This is very unlikely, but theoretically possible. Kick * just in case. */ if (unlikely(vq->num_added == (1 << 16) - 1)) virtqueue_kick(_vq); return 0; unmap_release: err_idx = i; if (indirect) i = 0; else i = head; for (n = 0; n < total_sg; n++) { if (i == err_idx) break; vring_unmap_one_split(vq, &desc[i]); i = virtio16_to_cpu(_vq->vdev, desc[i].next); } if (indirect) kfree(desc); END_USE(vq); return -ENOMEM; } static bool virtqueue_kick_prepare_split(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); u16 new, old; bool needs_kick; START_USE(vq); /* We need to expose available array entries before checking avail * event. */ virtio_mb(vq->weak_barriers); old = vq->split.avail_idx_shadow - vq->num_added; new = vq->split.avail_idx_shadow; vq->num_added = 0; LAST_ADD_TIME_CHECK(vq); LAST_ADD_TIME_INVALID(vq); if (vq->event) { needs_kick = vring_need_event(virtio16_to_cpu(_vq->vdev, vring_avail_event(&vq->split.vring)), new, old); } else { needs_kick = !(vq->split.vring.used->flags & cpu_to_virtio16(_vq->vdev, VRING_USED_F_NO_NOTIFY)); } END_USE(vq); return needs_kick; } static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, void **ctx) { unsigned int i, j; __virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT); /* Clear data ptr. */ vq->split.desc_state[head].data = NULL; /* Put back on free list: unmap first-level descriptors and find end */ i = head; while (vq->split.vring.desc[i].flags & nextflag) { vring_unmap_one_split(vq, &vq->split.vring.desc[i]); i = virtio16_to_cpu(vq->vq.vdev, vq->split.vring.desc[i].next); vq->vq.num_free++; } vring_unmap_one_split(vq, &vq->split.vring.desc[i]); vq->split.vring.desc[i].next = cpu_to_virtio16(vq->vq.vdev, vq->free_head); vq->free_head = head; /* Plus final descriptor */ vq->vq.num_free++; if (vq->indirect) { struct vring_desc *indir_desc = vq->split.desc_state[head].indir_desc; u32 len; /* Free the indirect table, if any, now that it's unmapped. */ if (!indir_desc) return; len = virtio32_to_cpu(vq->vq.vdev, vq->split.vring.desc[head].len); BUG_ON(!(vq->split.vring.desc[head].flags & cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT))); BUG_ON(len == 0 || len % sizeof(struct vring_desc)); for (j = 0; j < len / sizeof(struct vring_desc); j++) vring_unmap_one_split(vq, &indir_desc[j]); kfree(indir_desc); vq->split.desc_state[head].indir_desc = NULL; } else if (ctx) { *ctx = vq->split.desc_state[head].indir_desc; } } static inline bool more_used_split(const struct vring_virtqueue *vq) { return vq->last_used_idx != virtio16_to_cpu(vq->vq.vdev, vq->split.vring.used->idx); } static void *virtqueue_get_buf_ctx_split(struct virtqueue *_vq, unsigned int *len, void **ctx) { struct vring_virtqueue *vq = to_vvq(_vq); void *ret; unsigned int i; u16 last_used; START_USE(vq); if (unlikely(vq->broken)) { END_USE(vq); return NULL; } if (!more_used_split(vq)) { pr_debug("No more buffers in queue\n"); END_USE(vq); return NULL; } /* Only get used array entries after they have been exposed by host. */ virtio_rmb(vq->weak_barriers); last_used = (vq->last_used_idx & (vq->split.vring.num - 1)); i = virtio32_to_cpu(_vq->vdev, vq->split.vring.used->ring[last_used].id); *len = virtio32_to_cpu(_vq->vdev, vq->split.vring.used->ring[last_used].len); if (unlikely(i >= vq->split.vring.num)) { BAD_RING(vq, "id %u out of range\n", i); return NULL; } if (unlikely(!vq->split.desc_state[i].data)) { BAD_RING(vq, "id %u is not a head!\n", i); return NULL; } /* detach_buf_split clears data, so grab it now. */ ret = vq->split.desc_state[i].data; detach_buf_split(vq, i, ctx); vq->last_used_idx++; /* If we expect an interrupt for the next entry, tell host * by writing event index and flush out the write before * the read in the next get_buf call. */ if (!(vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) virtio_store_mb(vq->weak_barriers, &vring_used_event(&vq->split.vring), cpu_to_virtio16(_vq->vdev, vq->last_used_idx)); LAST_ADD_TIME_INVALID(vq); END_USE(vq); return ret; } static void virtqueue_disable_cb_split(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); if (!(vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) { vq->split.avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT; if (!vq->event) vq->split.vring.avail->flags = cpu_to_virtio16(_vq->vdev, vq->split.avail_flags_shadow); } } static unsigned virtqueue_enable_cb_prepare_split(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); u16 last_used_idx; START_USE(vq); /* We optimistically turn back on interrupts, then check if there was * more to do. */ /* Depending on the VIRTIO_RING_F_EVENT_IDX feature, we need to * either clear the flags bit or point the event index at the next * entry. Always do both to keep code simple. */ if (vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) { vq->split.avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT; if (!vq->event) vq->split.vring.avail->flags = cpu_to_virtio16(_vq->vdev, vq->split.avail_flags_shadow); } vring_used_event(&vq->split.vring) = cpu_to_virtio16(_vq->vdev, last_used_idx = vq->last_used_idx); END_USE(vq); return last_used_idx; } static bool virtqueue_poll_split(struct virtqueue *_vq, unsigned last_used_idx) { struct vring_virtqueue *vq = to_vvq(_vq); return (u16)last_used_idx != virtio16_to_cpu(_vq->vdev, vq->split.vring.used->idx); } static bool virtqueue_enable_cb_delayed_split(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); u16 bufs; START_USE(vq); /* We optimistically turn back on interrupts, then check if there was * more to do. */ /* Depending on the VIRTIO_RING_F_USED_EVENT_IDX feature, we need to * either clear the flags bit or point the event index at the next * entry. Always update the event index to keep code simple. */ if (vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) { vq->split.avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT; if (!vq->event) vq->split.vring.avail->flags = cpu_to_virtio16(_vq->vdev, vq->split.avail_flags_shadow); } /* TODO: tune this threshold */ bufs = (u16)(vq->split.avail_idx_shadow - vq->last_used_idx) * 3 / 4; virtio_store_mb(vq->weak_barriers, &vring_used_event(&vq->split.vring), cpu_to_virtio16(_vq->vdev, vq->last_used_idx + bufs)); if (unlikely((u16)(virtio16_to_cpu(_vq->vdev, vq->split.vring.used->idx) - vq->last_used_idx) > bufs)) { END_USE(vq); return false; } END_USE(vq); return true; } static void *virtqueue_detach_unused_buf_split(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); unsigned int i; void *buf; START_USE(vq); for (i = 0; i < vq->split.vring.num; i++) { if (!vq->split.desc_state[i].data) continue; /* detach_buf_split clears data, so grab it now. */ buf = vq->split.desc_state[i].data; detach_buf_split(vq, i, NULL); vq->split.avail_idx_shadow--; vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev, vq->split.avail_idx_shadow); END_USE(vq); return buf; } /* That should have freed everything. */ BUG_ON(vq->vq.num_free != vq->split.vring.num); END_USE(vq); return NULL; } static struct virtqueue *vring_create_virtqueue_split( unsigned int index, unsigned int num, unsigned int vring_align, struct virtio_device *vdev, bool weak_barriers, bool may_reduce_num, bool context, bool (*notify)(struct virtqueue *), void (*callback)(struct virtqueue *), const char *name) { struct virtqueue *vq; void *queue = NULL; dma_addr_t dma_addr; size_t queue_size_in_bytes; struct vring vring; /* We assume num is a power of 2. */ if (num & (num - 1)) { dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num); return NULL; } /* TODO: allocate each queue chunk individually */ for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) { queue = vring_alloc_queue(vdev, vring_size(num, vring_align), &dma_addr, GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO); if (queue) break; if (!may_reduce_num) return NULL; } if (!num) return NULL; if (!queue) { /* Try to get a single page. You are my only hope! */ queue = vring_alloc_queue(vdev, vring_size(num, vring_align), &dma_addr, GFP_KERNEL|__GFP_ZERO); } if (!queue) return NULL; queue_size_in_bytes = vring_size(num, vring_align); vring_init(&vring, num, queue, vring_align); vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers, context, notify, callback, name); if (!vq) { vring_free_queue(vdev, queue_size_in_bytes, queue, dma_addr); return NULL; } to_vvq(vq)->split.queue_dma_addr = dma_addr; to_vvq(vq)->split.queue_size_in_bytes = queue_size_in_bytes; to_vvq(vq)->we_own_ring = true; return vq; } /* * Packed ring specific functions - *_packed(). */ static void vring_unmap_state_packed(const struct vring_virtqueue *vq, struct vring_desc_extra_packed *state) { u16 flags; if (!vq->use_dma_api) return; flags = state->flags; if (flags & VRING_DESC_F_INDIRECT) { dma_unmap_single(vring_dma_dev(vq), state->addr, state->len, (flags & VRING_DESC_F_WRITE) ? DMA_FROM_DEVICE : DMA_TO_DEVICE); } else { dma_unmap_page(vring_dma_dev(vq), state->addr, state->len, (flags & VRING_DESC_F_WRITE) ? DMA_FROM_DEVICE : DMA_TO_DEVICE); } } static void vring_unmap_desc_packed(const struct vring_virtqueue *vq, struct vring_packed_desc *desc) { u16 flags; if (!vq->use_dma_api) return; flags = le16_to_cpu(desc->flags); if (flags & VRING_DESC_F_INDIRECT) { dma_unmap_single(vring_dma_dev(vq), le64_to_cpu(desc->addr), le32_to_cpu(desc->len), (flags & VRING_DESC_F_WRITE) ? DMA_FROM_DEVICE : DMA_TO_DEVICE); } else { dma_unmap_page(vring_dma_dev(vq), le64_to_cpu(desc->addr), le32_to_cpu(desc->len), (flags & VRING_DESC_F_WRITE) ? DMA_FROM_DEVICE : DMA_TO_DEVICE); } } static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg, gfp_t gfp) { struct vring_packed_desc *desc; /* * We require lowmem mappings for the descriptors because * otherwise virt_to_phys will give us bogus addresses in the * virtqueue. */ gfp &= ~__GFP_HIGHMEM; desc = kmalloc_array(total_sg, sizeof(struct vring_packed_desc), gfp); return desc; } static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, struct scatterlist *sgs[], unsigned int total_sg, unsigned int out_sgs, unsigned int in_sgs, void *data, gfp_t gfp) { struct vring_packed_desc *desc; struct scatterlist *sg; unsigned int i, n, err_idx; u16 head, id; dma_addr_t addr; head = vq->packed.next_avail_idx; desc = alloc_indirect_packed(total_sg, gfp); if (unlikely(vq->vq.num_free < 1)) { pr_debug("Can't add buf len 1 - avail = 0\n"); kfree(desc); END_USE(vq); return -ENOSPC; } i = 0; id = vq->free_head; BUG_ON(id == vq->packed.vring.num); for (n = 0; n < out_sgs + in_sgs; n++) { for (sg = sgs[n]; sg; sg = sg_next(sg)) { addr = vring_map_one_sg(vq, sg, n < out_sgs ? DMA_TO_DEVICE : DMA_FROM_DEVICE); if (vring_mapping_error(vq, addr)) goto unmap_release; desc[i].flags = cpu_to_le16(n < out_sgs ? 0 : VRING_DESC_F_WRITE); desc[i].addr = cpu_to_le64(addr); desc[i].len = cpu_to_le32(sg->length); i++; } } /* Now that the indirect table is filled in, map it. */ addr = vring_map_single(vq, desc, total_sg * sizeof(struct vring_packed_desc), DMA_TO_DEVICE); if (vring_mapping_error(vq, addr)) goto unmap_release; vq->packed.vring.desc[head].addr = cpu_to_le64(addr); vq->packed.vring.desc[head].len = cpu_to_le32(total_sg * sizeof(struct vring_packed_desc)); vq->packed.vring.desc[head].id = cpu_to_le16(id); if (vq->use_dma_api) { vq->packed.desc_extra[id].addr = addr; vq->packed.desc_extra[id].len = total_sg * sizeof(struct vring_packed_desc); vq->packed.desc_extra[id].flags = VRING_DESC_F_INDIRECT | vq->packed.avail_used_flags; } /* * A driver MUST NOT make the first descriptor in the list * available before all subsequent descriptors comprising * the list are made available. */ virtio_wmb(vq->weak_barriers); vq->packed.vring.desc[head].flags = cpu_to_le16(VRING_DESC_F_INDIRECT | vq->packed.avail_used_flags); /* We're using some buffers from the free list. */ vq->vq.num_free -= 1; /* Update free pointer */ n = head + 1; if (n >= vq->packed.vring.num) { n = 0; vq->packed.avail_wrap_counter ^= 1; vq->packed.avail_used_flags ^= 1 << VRING_PACKED_DESC_F_AVAIL | 1 << VRING_PACKED_DESC_F_USED; } vq->packed.next_avail_idx = n; vq->free_head = vq->packed.desc_state[id].next; /* Store token and indirect buffer state. */ vq->packed.desc_state[id].num = 1; vq->packed.desc_state[id].data = data; vq->packed.desc_state[id].indir_desc = desc; vq->packed.desc_state[id].last = id; vq->num_added += 1; pr_debug("Added buffer head %i to %p\n", head, vq); END_USE(vq); return 0; unmap_release: err_idx = i; for (i = 0; i < err_idx; i++) vring_unmap_desc_packed(vq, &desc[i]); kfree(desc); END_USE(vq); return -ENOMEM; } static inline int virtqueue_add_packed(struct virtqueue *_vq, struct scatterlist *sgs[], unsigned int total_sg, unsigned int out_sgs, unsigned int in_sgs, void *data, void *ctx, gfp_t gfp) { struct vring_virtqueue *vq = to_vvq(_vq); struct vring_packed_desc *desc; struct scatterlist *sg; unsigned int i, n, c, descs_used, err_idx; __le16 uninitialized_var(head_flags), flags; u16 head, id, uninitialized_var(prev), curr, avail_used_flags; START_USE(vq); BUG_ON(data == NULL); BUG_ON(ctx && vq->indirect); if (unlikely(vq->broken)) { END_USE(vq); return -EIO; } LAST_ADD_TIME_UPDATE(vq); BUG_ON(total_sg == 0); if (virtqueue_use_indirect(_vq, total_sg)) return virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs, in_sgs, data, gfp); head = vq->packed.next_avail_idx; avail_used_flags = vq->packed.avail_used_flags; WARN_ON_ONCE(total_sg > vq->packed.vring.num && !vq->indirect); desc = vq->packed.vring.desc; i = head; descs_used = total_sg; if (unlikely(vq->vq.num_free < descs_used)) { pr_debug("Can't add buf len %i - avail = %i\n", descs_used, vq->vq.num_free); END_USE(vq); return -ENOSPC; } id = vq->free_head; BUG_ON(id == vq->packed.vring.num); curr = id; c = 0; for (n = 0; n < out_sgs + in_sgs; n++) { for (sg = sgs[n]; sg; sg = sg_next(sg)) { dma_addr_t addr = vring_map_one_sg(vq, sg, n < out_sgs ? DMA_TO_DEVICE : DMA_FROM_DEVICE); if (vring_mapping_error(vq, addr)) goto unmap_release; flags = cpu_to_le16(vq->packed.avail_used_flags | (++c == total_sg ? 0 : VRING_DESC_F_NEXT) | (n < out_sgs ? 0 : VRING_DESC_F_WRITE)); if (i == head) head_flags = flags; else desc[i].flags = flags; desc[i].addr = cpu_to_le64(addr); desc[i].len = cpu_to_le32(sg->length); desc[i].id = cpu_to_le16(id); if (unlikely(vq->use_dma_api)) { vq->packed.desc_extra[curr].addr = addr; vq->packed.desc_extra[curr].len = sg->length; vq->packed.desc_extra[curr].flags = le16_to_cpu(flags); } prev = curr; curr = vq->packed.desc_state[curr].next; if ((unlikely(++i >= vq->packed.vring.num))) { i = 0; vq->packed.avail_used_flags ^= 1 << VRING_PACKED_DESC_F_AVAIL | 1 << VRING_PACKED_DESC_F_USED; } } } if (i < head) vq->packed.avail_wrap_counter ^= 1; /* We're using some buffers from the free list. */ vq->vq.num_free -= descs_used; /* Update free pointer */ vq->packed.next_avail_idx = i; vq->free_head = curr; /* Store token. */ vq->packed.desc_state[id].num = descs_used; vq->packed.desc_state[id].data = data; vq->packed.desc_state[id].indir_desc = ctx; vq->packed.desc_state[id].last = prev; /* * A driver MUST NOT make the first descriptor in the list * available before all subsequent descriptors comprising * the list are made available. */ virtio_wmb(vq->weak_barriers); vq->packed.vring.desc[head].flags = head_flags; vq->num_added += descs_used; pr_debug("Added buffer head %i to %p\n", head, vq); END_USE(vq); return 0; unmap_release: err_idx = i; i = head; vq->packed.avail_used_flags = avail_used_flags; for (n = 0; n < total_sg; n++) { if (i == err_idx) break; vring_unmap_desc_packed(vq, &desc[i]); i++; if (i >= vq->packed.vring.num) i = 0; } END_USE(vq); return -EIO; } static bool virtqueue_kick_prepare_packed(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); u16 new, old, off_wrap, flags, wrap_counter, event_idx; bool needs_kick; union { struct { __le16 off_wrap; __le16 flags; }; u32 u32; } snapshot; START_USE(vq); /* * We need to expose the new flags value before checking notification * suppressions. */ virtio_mb(vq->weak_barriers); old = vq->packed.next_avail_idx - vq->num_added; new = vq->packed.next_avail_idx; vq->num_added = 0; snapshot.u32 = *(u32 *)vq->packed.vring.device; flags = le16_to_cpu(snapshot.flags); LAST_ADD_TIME_CHECK(vq); LAST_ADD_TIME_INVALID(vq); if (flags != VRING_PACKED_EVENT_FLAG_DESC) { needs_kick = (flags != VRING_PACKED_EVENT_FLAG_DISABLE); goto out; } off_wrap = le16_to_cpu(snapshot.off_wrap); wrap_counter = off_wrap >> VRING_PACKED_EVENT_F_WRAP_CTR; event_idx = off_wrap & ~(1 << VRING_PACKED_EVENT_F_WRAP_CTR); if (wrap_counter != vq->packed.avail_wrap_counter) event_idx -= vq->packed.vring.num; needs_kick = vring_need_event(event_idx, new, old); out: END_USE(vq); return needs_kick; } static void detach_buf_packed(struct vring_virtqueue *vq, unsigned int id, void **ctx) { struct vring_desc_state_packed *state = NULL; struct vring_packed_desc *desc; unsigned int i, curr; state = &vq->packed.desc_state[id]; /* Clear data ptr. */ state->data = NULL; vq->packed.desc_state[state->last].next = vq->free_head; vq->free_head = id; vq->vq.num_free += state->num; if (unlikely(vq->use_dma_api)) { curr = id; for (i = 0; i < state->num; i++) { vring_unmap_state_packed(vq, &vq->packed.desc_extra[curr]); curr = vq->packed.desc_state[curr].next; } } if (vq->indirect) { u32 len; /* Free the indirect table, if any, now that it's unmapped. */ desc = state->indir_desc; if (!desc) return; if (vq->use_dma_api) { len = vq->packed.desc_extra[id].len; for (i = 0; i < len / sizeof(struct vring_packed_desc); i++) vring_unmap_desc_packed(vq, &desc[i]); } kfree(desc); state->indir_desc = NULL; } else if (ctx) { *ctx = state->indir_desc; } } static inline bool is_used_desc_packed(const struct vring_virtqueue *vq, u16 idx, bool used_wrap_counter) { bool avail, used; u16 flags; flags = le16_to_cpu(vq->packed.vring.desc[idx].flags); avail = !!(flags & (1 << VRING_PACKED_DESC_F_AVAIL)); used = !!(flags & (1 << VRING_PACKED_DESC_F_USED)); return avail == used && used == used_wrap_counter; } static inline bool more_used_packed(const struct vring_virtqueue *vq) { return is_used_desc_packed(vq, vq->last_used_idx, vq->packed.used_wrap_counter); } static void *virtqueue_get_buf_ctx_packed(struct virtqueue *_vq, unsigned int *len, void **ctx) { struct vring_virtqueue *vq = to_vvq(_vq); u16 last_used, id; void *ret; START_USE(vq); if (unlikely(vq->broken)) { END_USE(vq); return NULL; } if (!more_used_packed(vq)) { pr_debug("No more buffers in queue\n"); END_USE(vq); return NULL; } /* Only get used elements after they have been exposed by host. */ virtio_rmb(vq->weak_barriers); last_used = vq->last_used_idx; id = le16_to_cpu(vq->packed.vring.desc[last_used].id); *len = le32_to_cpu(vq->packed.vring.desc[last_used].len); if (unlikely(id >= vq->packed.vring.num)) { BAD_RING(vq, "id %u out of range\n", id); return NULL; } if (unlikely(!vq->packed.desc_state[id].data)) { BAD_RING(vq, "id %u is not a head!\n", id); return NULL; } /* detach_buf_packed clears data, so grab it now. */ ret = vq->packed.desc_state[id].data; detach_buf_packed(vq, id, ctx); vq->last_used_idx += vq->packed.desc_state[id].num; if (unlikely(vq->last_used_idx >= vq->packed.vring.num)) { vq->last_used_idx -= vq->packed.vring.num; vq->packed.used_wrap_counter ^= 1; } /* * If we expect an interrupt for the next entry, tell host * by writing event index and flush out the write before * the read in the next get_buf call. */ if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DESC) virtio_store_mb(vq->weak_barriers, &vq->packed.vring.driver->off_wrap, cpu_to_le16(vq->last_used_idx | (vq->packed.used_wrap_counter << VRING_PACKED_EVENT_F_WRAP_CTR))); LAST_ADD_TIME_INVALID(vq); END_USE(vq); return ret; } static void virtqueue_disable_cb_packed(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); if (vq->packed.event_flags_shadow != VRING_PACKED_EVENT_FLAG_DISABLE) { vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE; vq->packed.vring.driver->flags = cpu_to_le16(vq->packed.event_flags_shadow); } } static unsigned virtqueue_enable_cb_prepare_packed(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); START_USE(vq); /* * We optimistically turn back on interrupts, then check if there was * more to do. */ if (vq->event) { vq->packed.vring.driver->off_wrap = cpu_to_le16(vq->last_used_idx | (vq->packed.used_wrap_counter << VRING_PACKED_EVENT_F_WRAP_CTR)); /* * We need to update event offset and event wrap * counter first before updating event flags. */ virtio_wmb(vq->weak_barriers); } if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DISABLE) { vq->packed.event_flags_shadow = vq->event ? VRING_PACKED_EVENT_FLAG_DESC : VRING_PACKED_EVENT_FLAG_ENABLE; vq->packed.vring.driver->flags = cpu_to_le16(vq->packed.event_flags_shadow); } END_USE(vq); return vq->last_used_idx | ((u16)vq->packed.used_wrap_counter << VRING_PACKED_EVENT_F_WRAP_CTR); } static bool virtqueue_poll_packed(struct virtqueue *_vq, u16 off_wrap) { struct vring_virtqueue *vq = to_vvq(_vq); bool wrap_counter; u16 used_idx; wrap_counter = off_wrap >> VRING_PACKED_EVENT_F_WRAP_CTR; used_idx = off_wrap & ~(1 << VRING_PACKED_EVENT_F_WRAP_CTR); return is_used_desc_packed(vq, used_idx, wrap_counter); } static bool virtqueue_enable_cb_delayed_packed(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); u16 used_idx, wrap_counter; u16 bufs; START_USE(vq); /* * We optimistically turn back on interrupts, then check if there was * more to do. */ if (vq->event) { /* TODO: tune this threshold */ bufs = (vq->packed.vring.num - vq->vq.num_free) * 3 / 4; wrap_counter = vq->packed.used_wrap_counter; used_idx = vq->last_used_idx + bufs; if (used_idx >= vq->packed.vring.num) { used_idx -= vq->packed.vring.num; wrap_counter ^= 1; } vq->packed.vring.driver->off_wrap = cpu_to_le16(used_idx | (wrap_counter << VRING_PACKED_EVENT_F_WRAP_CTR)); /* * We need to update event offset and event wrap * counter first before updating event flags. */ virtio_wmb(vq->weak_barriers); } if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DISABLE) { vq->packed.event_flags_shadow = vq->event ? VRING_PACKED_EVENT_FLAG_DESC : VRING_PACKED_EVENT_FLAG_ENABLE; vq->packed.vring.driver->flags = cpu_to_le16(vq->packed.event_flags_shadow); } /* * We need to update event suppression structure first * before re-checking for more used buffers. */ virtio_mb(vq->weak_barriers); if (is_used_desc_packed(vq, vq->last_used_idx, vq->packed.used_wrap_counter)) { END_USE(vq); return false; } END_USE(vq); return true; } static void *virtqueue_detach_unused_buf_packed(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); unsigned int i; void *buf; START_USE(vq); for (i = 0; i < vq->packed.vring.num; i++) { if (!vq->packed.desc_state[i].data) continue; /* detach_buf clears data, so grab it now. */ buf = vq->packed.desc_state[i].data; detach_buf_packed(vq, i, NULL); END_USE(vq); return buf; } /* That should have freed everything. */ BUG_ON(vq->vq.num_free != vq->packed.vring.num); END_USE(vq); return NULL; } static struct virtqueue *vring_create_virtqueue_packed( unsigned int index, unsigned int num, unsigned int vring_align, struct virtio_device *vdev, bool weak_barriers, bool may_reduce_num, bool context, bool (*notify)(struct virtqueue *), void (*callback)(struct virtqueue *), const char *name) { struct vring_virtqueue *vq; struct vring_packed_desc *ring; struct vring_packed_desc_event *driver, *device; dma_addr_t ring_dma_addr, driver_event_dma_addr, device_event_dma_addr; size_t ring_size_in_bytes, event_size_in_bytes; unsigned int i; ring_size_in_bytes = num * sizeof(struct vring_packed_desc); ring = vring_alloc_queue(vdev, ring_size_in_bytes, &ring_dma_addr, GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO); if (!ring) goto err_ring; event_size_in_bytes = sizeof(struct vring_packed_desc_event); driver = vring_alloc_queue(vdev, event_size_in_bytes, &driver_event_dma_addr, GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO); if (!driver) goto err_driver; device = vring_alloc_queue(vdev, event_size_in_bytes, &device_event_dma_addr, GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO); if (!device) goto err_device; vq = kmalloc(sizeof(*vq), GFP_KERNEL); if (!vq) goto err_vq; vq->vq.callback = callback; vq->vq.vdev = vdev; vq->vq.name = name; vq->vq.num_free = num; vq->vq.index = index; vq->we_own_ring = true; vq->notify = notify; vq->weak_barriers = weak_barriers; vq->broken = false; vq->last_used_idx = 0; vq->num_added = 0; vq->packed_ring = true; vq->use_dma_api = vring_use_dma_api(vdev); list_add_tail(&vq->vq.list, &vdev->vqs); #ifdef DEBUG vq->in_use = false; vq->last_add_time_valid = false; #endif vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) && !context; vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM)) vq->weak_barriers = false; vq->packed.ring_dma_addr = ring_dma_addr; vq->packed.driver_event_dma_addr = driver_event_dma_addr; vq->packed.device_event_dma_addr = device_event_dma_addr; vq->packed.ring_size_in_bytes = ring_size_in_bytes; vq->packed.event_size_in_bytes = event_size_in_bytes; vq->packed.vring.num = num; vq->packed.vring.desc = ring; vq->packed.vring.driver = driver; vq->packed.vring.device = device; vq->packed.next_avail_idx = 0; vq->packed.avail_wrap_counter = 1; vq->packed.used_wrap_counter = 1; vq->packed.event_flags_shadow = 0; vq->packed.avail_used_flags = 1 << VRING_PACKED_DESC_F_AVAIL; vq->packed.desc_state = kmalloc_array(num, sizeof(struct vring_desc_state_packed), GFP_KERNEL); if (!vq->packed.desc_state) goto err_desc_state; memset(vq->packed.desc_state, 0, num * sizeof(struct vring_desc_state_packed)); /* Put everything in free lists. */ vq->free_head = 0; for (i = 0; i < num-1; i++) vq->packed.desc_state[i].next = i + 1; vq->packed.desc_extra = kmalloc_array(num, sizeof(struct vring_desc_extra_packed), GFP_KERNEL); if (!vq->packed.desc_extra) goto err_desc_extra; memset(vq->packed.desc_extra, 0, num * sizeof(struct vring_desc_extra_packed)); /* No callback? Tell other side not to bother us. */ if (!callback) { vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE; vq->packed.vring.driver->flags = cpu_to_le16(vq->packed.event_flags_shadow); } return &vq->vq; err_desc_extra: kfree(vq->packed.desc_state); err_desc_state: kfree(vq); err_vq: vring_free_queue(vdev, event_size_in_bytes, device, ring_dma_addr); err_device: vring_free_queue(vdev, event_size_in_bytes, driver, ring_dma_addr); err_driver: vring_free_queue(vdev, ring_size_in_bytes, ring, ring_dma_addr); err_ring: return NULL; } /* * Generic functions and exported symbols. */ static inline int virtqueue_add(struct virtqueue *_vq, struct scatterlist *sgs[], unsigned int total_sg, unsigned int out_sgs, unsigned int in_sgs, void *data, void *ctx, gfp_t gfp) { struct vring_virtqueue *vq = to_vvq(_vq); return vq->packed_ring ? virtqueue_add_packed(_vq, sgs, total_sg, out_sgs, in_sgs, data, ctx, gfp) : virtqueue_add_split(_vq, sgs, total_sg, out_sgs, in_sgs, data, ctx, gfp); } /** * virtqueue_add_sgs - expose buffers to other end * @_vq: the struct virtqueue we're talking about. * @sgs: array of terminated scatterlists. * @out_sgs: the number of scatterlists readable by other side * @in_sgs: the number of scatterlists which are writable (after readable ones) * @data: the token identifying the buffer. * @gfp: how to do memory allocations (if necessary). * * Caller must ensure we don't call this with other virtqueue operations * at the same time (except where noted). * * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). */ int virtqueue_add_sgs(struct virtqueue *_vq, struct scatterlist *sgs[], unsigned int out_sgs, unsigned int in_sgs, void *data, gfp_t gfp) { unsigned int i, total_sg = 0; /* Count them first. */ for (i = 0; i < out_sgs + in_sgs; i++) { struct scatterlist *sg; for (sg = sgs[i]; sg; sg = sg_next(sg)) total_sg++; } return virtqueue_add(_vq, sgs, total_sg, out_sgs, in_sgs, data, NULL, gfp); } EXPORT_SYMBOL_GPL(virtqueue_add_sgs); /** * virtqueue_add_outbuf - expose output buffers to other end * @vq: the struct virtqueue we're talking about. * @sg: scatterlist (must be well-formed and terminated!) * @num: the number of entries in @sg readable by other side * @data: the token identifying the buffer. * @gfp: how to do memory allocations (if necessary). * * Caller must ensure we don't call this with other virtqueue operations * at the same time (except where noted). * * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). */ int virtqueue_add_outbuf(struct virtqueue *vq, struct scatterlist *sg, unsigned int num, void *data, gfp_t gfp) { return virtqueue_add(vq, &sg, num, 1, 0, data, NULL, gfp); } EXPORT_SYMBOL_GPL(virtqueue_add_outbuf); /** * virtqueue_add_inbuf - expose input buffers to other end * @vq: the struct virtqueue we're talking about. * @sg: scatterlist (must be well-formed and terminated!) * @num: the number of entries in @sg writable by other side * @data: the token identifying the buffer. * @gfp: how to do memory allocations (if necessary). * * Caller must ensure we don't call this with other virtqueue operations * at the same time (except where noted). * * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). */ int virtqueue_add_inbuf(struct virtqueue *vq, struct scatterlist *sg, unsigned int num, void *data, gfp_t gfp) { return virtqueue_add(vq, &sg, num, 0, 1, data, NULL, gfp); } EXPORT_SYMBOL_GPL(virtqueue_add_inbuf); /** * virtqueue_add_inbuf_ctx - expose input buffers to other end * @vq: the struct virtqueue we're talking about. * @sg: scatterlist (must be well-formed and terminated!) * @num: the number of entries in @sg writable by other side * @data: the token identifying the buffer. * @ctx: extra context for the token * @gfp: how to do memory allocations (if necessary). * * Caller must ensure we don't call this with other virtqueue operations * at the same time (except where noted). * * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). */ int virtqueue_add_inbuf_ctx(struct virtqueue *vq, struct scatterlist *sg, unsigned int num, void *data, void *ctx, gfp_t gfp) { return virtqueue_add(vq, &sg, num, 0, 1, data, ctx, gfp); } EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_ctx); /** * virtqueue_kick_prepare - first half of split virtqueue_kick call. * @_vq: the struct virtqueue * * Instead of virtqueue_kick(), you can do: * if (virtqueue_kick_prepare(vq)) * virtqueue_notify(vq); * * This is sometimes useful because the virtqueue_kick_prepare() needs * to be serialized, but the actual virtqueue_notify() call does not. */ bool virtqueue_kick_prepare(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); return vq->packed_ring ? virtqueue_kick_prepare_packed(_vq) : virtqueue_kick_prepare_split(_vq); } EXPORT_SYMBOL_GPL(virtqueue_kick_prepare); /** * virtqueue_notify - second half of split virtqueue_kick call. * @_vq: the struct virtqueue * * This does not need to be serialized. * * Returns false if host notify failed or queue is broken, otherwise true. */ bool virtqueue_notify(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); if (unlikely(vq->broken)) return false; /* Prod other side to tell it about changes. */ if (!vq->notify(_vq)) { vq->broken = true; return false; } return true; } EXPORT_SYMBOL_GPL(virtqueue_notify); /** * virtqueue_kick - update after add_buf * @vq: the struct virtqueue * * After one or more virtqueue_add_* calls, invoke this to kick * the other side. * * Caller must ensure we don't call this with other virtqueue * operations at the same time (except where noted). * * Returns false if kick failed, otherwise true. */ bool virtqueue_kick(struct virtqueue *vq) { if (virtqueue_kick_prepare(vq)) return virtqueue_notify(vq); return true; } EXPORT_SYMBOL_GPL(virtqueue_kick); /** * virtqueue_get_buf - get the next used buffer * @_vq: the struct virtqueue we're talking about. * @len: the length written into the buffer * @ctx: extra context for the token * * If the device wrote data into the buffer, @len will be set to the * amount written. This means you don't need to clear the buffer * beforehand to ensure there's no data leakage in the case of short * writes. * * Caller must ensure we don't call this with other virtqueue * operations at the same time (except where noted). * * Returns NULL if there are no used buffers, or the "data" token * handed to virtqueue_add_*(). */ void *virtqueue_get_buf_ctx(struct virtqueue *_vq, unsigned int *len, void **ctx) { struct vring_virtqueue *vq = to_vvq(_vq); return vq->packed_ring ? virtqueue_get_buf_ctx_packed(_vq, len, ctx) : virtqueue_get_buf_ctx_split(_vq, len, ctx); } EXPORT_SYMBOL_GPL(virtqueue_get_buf_ctx); void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len) { return virtqueue_get_buf_ctx(_vq, len, NULL); } EXPORT_SYMBOL_GPL(virtqueue_get_buf); /** * virtqueue_disable_cb - disable callbacks * @_vq: the struct virtqueue we're talking about. * * Note that this is not necessarily synchronous, hence unreliable and only * useful as an optimization. * * Unlike other operations, this need not be serialized. */ void virtqueue_disable_cb(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); if (vq->packed_ring) virtqueue_disable_cb_packed(_vq); else virtqueue_disable_cb_split(_vq); } EXPORT_SYMBOL_GPL(virtqueue_disable_cb); /** * virtqueue_enable_cb_prepare - restart callbacks after disable_cb * @_vq: the struct virtqueue we're talking about. * * This re-enables callbacks; it returns current queue state * in an opaque unsigned value. This value should be later tested by * virtqueue_poll, to detect a possible race between the driver checking for * more work, and enabling callbacks. * * Caller must ensure we don't call this with other virtqueue * operations at the same time (except where noted). */ unsigned virtqueue_enable_cb_prepare(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); return vq->packed_ring ? virtqueue_enable_cb_prepare_packed(_vq) : virtqueue_enable_cb_prepare_split(_vq); } EXPORT_SYMBOL_GPL(virtqueue_enable_cb_prepare); /** * virtqueue_poll - query pending used buffers * @_vq: the struct virtqueue we're talking about. * @last_used_idx: virtqueue state (from call to virtqueue_enable_cb_prepare). * * Returns "true" if there are pending used buffers in the queue. * * This does not need to be serialized. */ bool virtqueue_poll(struct virtqueue *_vq, unsigned last_used_idx) { struct vring_virtqueue *vq = to_vvq(_vq); virtio_mb(vq->weak_barriers); return vq->packed_ring ? virtqueue_poll_packed(_vq, last_used_idx) : virtqueue_poll_split(_vq, last_used_idx); } EXPORT_SYMBOL_GPL(virtqueue_poll); /** * virtqueue_enable_cb - restart callbacks after disable_cb. * @_vq: the struct virtqueue we're talking about. * * This re-enables callbacks; it returns "false" if there are pending * buffers in the queue, to detect a possible race between the driver * checking for more work, and enabling callbacks. * * Caller must ensure we don't call this with other virtqueue * operations at the same time (except where noted). */ bool virtqueue_enable_cb(struct virtqueue *_vq) { unsigned last_used_idx = virtqueue_enable_cb_prepare(_vq); return !virtqueue_poll(_vq, last_used_idx); } EXPORT_SYMBOL_GPL(virtqueue_enable_cb); /** * virtqueue_enable_cb_delayed - restart callbacks after disable_cb. * @_vq: the struct virtqueue we're talking about. * * This re-enables callbacks but hints to the other side to delay * interrupts until most of the available buffers have been processed; * it returns "false" if there are many pending buffers in the queue, * to detect a possible race between the driver checking for more work, * and enabling callbacks. * * Caller must ensure we don't call this with other virtqueue * operations at the same time (except where noted). */ bool virtqueue_enable_cb_delayed(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); return vq->packed_ring ? virtqueue_enable_cb_delayed_packed(_vq) : virtqueue_enable_cb_delayed_split(_vq); } EXPORT_SYMBOL_GPL(virtqueue_enable_cb_delayed); /** * virtqueue_detach_unused_buf - detach first unused buffer * @_vq: the struct virtqueue we're talking about. * * Returns NULL or the "data" token handed to virtqueue_add_*(). * This is not valid on an active queue; it is useful only for device * shutdown. */ void *virtqueue_detach_unused_buf(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); return vq->packed_ring ? virtqueue_detach_unused_buf_packed(_vq) : virtqueue_detach_unused_buf_split(_vq); } EXPORT_SYMBOL_GPL(virtqueue_detach_unused_buf); static inline bool more_used(const struct vring_virtqueue *vq) { return vq->packed_ring ? more_used_packed(vq) : more_used_split(vq); } irqreturn_t vring_interrupt(int irq, void *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); if (!more_used(vq)) { pr_debug("virtqueue interrupt with no work for %p\n", vq); return IRQ_NONE; } if (unlikely(vq->broken)) return IRQ_HANDLED; pr_debug("virtqueue callback for %p (%p)\n", vq, vq->vq.callback); if (vq->vq.callback) vq->vq.callback(&vq->vq); return IRQ_HANDLED; } EXPORT_SYMBOL_GPL(vring_interrupt); /* Only available for split ring */ struct virtqueue *__vring_new_virtqueue(unsigned int index, struct vring vring, struct virtio_device *vdev, bool weak_barriers, bool context, bool (*notify)(struct virtqueue *), void (*callback)(struct virtqueue *), const char *name) { unsigned int i; struct vring_virtqueue *vq; if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED)) return NULL; vq = kmalloc(sizeof(*vq), GFP_KERNEL); if (!vq) return NULL; vq->packed_ring = false; vq->vq.callback = callback; vq->vq.vdev = vdev; vq->vq.name = name; vq->vq.num_free = vring.num; vq->vq.index = index; vq->we_own_ring = false; vq->notify = notify; vq->weak_barriers = weak_barriers; vq->broken = false; vq->last_used_idx = 0; vq->num_added = 0; vq->use_dma_api = vring_use_dma_api(vdev); list_add_tail(&vq->vq.list, &vdev->vqs); #ifdef DEBUG vq->in_use = false; vq->last_add_time_valid = false; #endif vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) && !context; vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM)) vq->weak_barriers = false; vq->split.queue_dma_addr = 0; vq->split.queue_size_in_bytes = 0; vq->split.vring = vring; vq->split.avail_flags_shadow = 0; vq->split.avail_idx_shadow = 0; /* No callback? Tell other side not to bother us. */ if (!callback) { vq->split.avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT; if (!vq->event) vq->split.vring.avail->flags = cpu_to_virtio16(vdev, vq->split.avail_flags_shadow); } vq->split.desc_state = kmalloc_array(vring.num, sizeof(struct vring_desc_state_split), GFP_KERNEL); if (!vq->split.desc_state) { kfree(vq); return NULL; } /* Put everything in free lists. */ vq->free_head = 0; for (i = 0; i < vring.num-1; i++) vq->split.vring.desc[i].next = cpu_to_virtio16(vdev, i + 1); memset(vq->split.desc_state, 0, vring.num * sizeof(struct vring_desc_state_split)); return &vq->vq; } EXPORT_SYMBOL_GPL(__vring_new_virtqueue); struct virtqueue *vring_create_virtqueue( unsigned int index, unsigned int num, unsigned int vring_align, struct virtio_device *vdev, bool weak_barriers, bool may_reduce_num, bool context, bool (*notify)(struct virtqueue *), void (*callback)(struct virtqueue *), const char *name) { if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED)) return vring_create_virtqueue_packed(index, num, vring_align, vdev, weak_barriers, may_reduce_num, context, notify, callback, name); return vring_create_virtqueue_split(index, num, vring_align, vdev, weak_barriers, may_reduce_num, context, notify, callback, name); } EXPORT_SYMBOL_GPL(vring_create_virtqueue); /* Only available for split ring */ struct virtqueue *vring_new_virtqueue(unsigned int index, unsigned int num, unsigned int vring_align, struct virtio_device *vdev, bool weak_barriers, bool context, void *pages, bool (*notify)(struct virtqueue *vq), void (*callback)(struct virtqueue *vq), const char *name) { struct vring vring; if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED)) return NULL; vring_init(&vring, num, pages, vring_align); return __vring_new_virtqueue(index, vring, vdev, weak_barriers, context, notify, callback, name); } EXPORT_SYMBOL_GPL(vring_new_virtqueue); void vring_del_virtqueue(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); if (vq->we_own_ring) { if (vq->packed_ring) { vring_free_queue(vq->vq.vdev, vq->packed.ring_size_in_bytes, vq->packed.vring.desc, vq->packed.ring_dma_addr); vring_free_queue(vq->vq.vdev, vq->packed.event_size_in_bytes, vq->packed.vring.driver, vq->packed.driver_event_dma_addr); vring_free_queue(vq->vq.vdev, vq->packed.event_size_in_bytes, vq->packed.vring.device, vq->packed.device_event_dma_addr); kfree(vq->packed.desc_state); kfree(vq->packed.desc_extra); } else { vring_free_queue(vq->vq.vdev, vq->split.queue_size_in_bytes, vq->split.vring.desc, vq->split.queue_dma_addr); } } if (!vq->packed_ring) kfree(vq->split.desc_state); list_del(&_vq->list); kfree(vq); } EXPORT_SYMBOL_GPL(vring_del_virtqueue); /* Manipulates transport-specific feature bits. */ void vring_transport_features(struct virtio_device *vdev) { unsigned int i; for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) { switch (i) { case VIRTIO_RING_F_INDIRECT_DESC: break; case VIRTIO_RING_F_EVENT_IDX: break; case VIRTIO_F_VERSION_1: break; case VIRTIO_F_IOMMU_PLATFORM: break; case VIRTIO_F_RING_PACKED: break; case VIRTIO_F_ORDER_PLATFORM: break; default: /* We don't understand this bit. */ __virtio_clear_bit(vdev, i); } } } EXPORT_SYMBOL_GPL(vring_transport_features); /** * virtqueue_get_vring_size - return the size of the virtqueue's vring * @_vq: the struct virtqueue containing the vring of interest. * * Returns the size of the vring. This is mainly used for boasting to * userspace. Unlike other operations, this need not be serialized. */ unsigned int virtqueue_get_vring_size(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); return vq->packed_ring ? vq->packed.vring.num : vq->split.vring.num; } EXPORT_SYMBOL_GPL(virtqueue_get_vring_size); bool virtqueue_is_broken(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); return vq->broken; } EXPORT_SYMBOL_GPL(virtqueue_is_broken); /* * This should prevent the device from being used, allowing drivers to * recover. You may need to grab appropriate locks to flush. */ void virtio_break_device(struct virtio_device *dev) { struct virtqueue *_vq; list_for_each_entry(_vq, &dev->vqs, list) { struct vring_virtqueue *vq = to_vvq(_vq); vq->broken = true; } } EXPORT_SYMBOL_GPL(virtio_break_device); dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); BUG_ON(!vq->we_own_ring); if (vq->packed_ring) return vq->packed.ring_dma_addr; return vq->split.queue_dma_addr; } EXPORT_SYMBOL_GPL(virtqueue_get_desc_addr); dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); BUG_ON(!vq->we_own_ring); if (vq->packed_ring) return vq->packed.driver_event_dma_addr; return vq->split.queue_dma_addr + ((char *)vq->split.vring.avail - (char *)vq->split.vring.desc); } EXPORT_SYMBOL_GPL(virtqueue_get_avail_addr); dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); BUG_ON(!vq->we_own_ring); if (vq->packed_ring) return vq->packed.device_event_dma_addr; return vq->split.queue_dma_addr + ((char *)vq->split.vring.used - (char *)vq->split.vring.desc); } EXPORT_SYMBOL_GPL(virtqueue_get_used_addr); /* Only available for split ring */ const struct vring *virtqueue_get_vring(struct virtqueue *vq) { return &to_vvq(vq)->split.vring; } EXPORT_SYMBOL_GPL(virtqueue_get_vring); MODULE_LICENSE("GPL");
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