/* * Virtio Support * * Copyright IBM, Corp. 2007 * * Authors: * Anthony Liguori <aliguori@us.ibm.com> * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. * */ #include <inttypes.h> #include "virtio.h" #include "sysemu.h" /* The alignment to use between consumer and producer parts of vring. * x86 pagesize again. */ #define VIRTIO_PCI_VRING_ALIGN 4096 /* QEMU doesn't strictly need write barriers since everything runs in * lock-step. We'll leave the calls to wmb() in though to make it obvious for * KVM or if kqemu gets SMP support. * In any case, we must prevent the compiler from reordering the code. * TODO: we likely need some rmb()/mb() as well. */ #define wmb() __asm__ __volatile__("": : :"memory") typedef struct VRingDesc { uint64_t addr; uint32_t len; uint16_t flags; uint16_t next; } VRingDesc; typedef struct VRingAvail { uint16_t flags; uint16_t idx; uint16_t ring[0]; } VRingAvail; typedef struct VRingUsedElem { uint32_t id; uint32_t len; } VRingUsedElem; typedef struct VRingUsed { uint16_t flags; uint16_t idx; VRingUsedElem ring[0]; } VRingUsed; typedef struct VRing { unsigned int num; target_phys_addr_t desc; target_phys_addr_t avail; target_phys_addr_t used; } VRing; struct VirtQueue { VRing vring; target_phys_addr_t pa; uint16_t last_avail_idx; int inuse; uint16_t vector; void (*handle_output)(VirtIODevice *vdev, VirtQueue *vq); VirtIODevice *vdev; EventNotifier guest_notifier; EventNotifier host_notifier; }; /* virt queue functions */ static void virtqueue_init(VirtQueue *vq) { target_phys_addr_t pa = vq->pa; vq->vring.desc = pa; vq->vring.avail = pa + vq->vring.num * sizeof(VRingDesc); vq->vring.used = vring_align(vq->vring.avail + offsetof(VRingAvail, ring[vq->vring.num]), VIRTIO_PCI_VRING_ALIGN); } static inline uint64_t vring_desc_addr(target_phys_addr_t desc_pa, int i) { target_phys_addr_t pa; pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, addr); return ldq_phys(pa); } static inline uint32_t vring_desc_len(target_phys_addr_t desc_pa, int i) { target_phys_addr_t pa; pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, len); return ldl_phys(pa); } static inline uint16_t vring_desc_flags(target_phys_addr_t desc_pa, int i) { target_phys_addr_t pa; pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, flags); return lduw_phys(pa); } static inline uint16_t vring_desc_next(target_phys_addr_t desc_pa, int i) { target_phys_addr_t pa; pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, next); return lduw_phys(pa); } static inline uint16_t vring_avail_flags(VirtQueue *vq) { target_phys_addr_t pa; pa = vq->vring.avail + offsetof(VRingAvail, flags); return lduw_phys(pa); } static inline uint16_t vring_avail_idx(VirtQueue *vq) { target_phys_addr_t pa; pa = vq->vring.avail + offsetof(VRingAvail, idx); return lduw_phys(pa); } static inline uint16_t vring_avail_ring(VirtQueue *vq, int i) { target_phys_addr_t pa; pa = vq->vring.avail + offsetof(VRingAvail, ring[i]); return lduw_phys(pa); } static inline void vring_used_ring_id(VirtQueue *vq, int i, uint32_t val) { target_phys_addr_t pa; pa = vq->vring.used + offsetof(VRingUsed, ring[i].id); stl_phys(pa, val); } static inline void vring_used_ring_len(VirtQueue *vq, int i, uint32_t val) { target_phys_addr_t pa; pa = vq->vring.used + offsetof(VRingUsed, ring[i].len); stl_phys(pa, val); } static uint16_t vring_used_idx(VirtQueue *vq) { target_phys_addr_t pa; pa = vq->vring.used + offsetof(VRingUsed, idx); return lduw_phys(pa); } static inline void vring_used_idx_increment(VirtQueue *vq, uint16_t val) { target_phys_addr_t pa; pa = vq->vring.used + offsetof(VRingUsed, idx); stw_phys(pa, vring_used_idx(vq) + val); } static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask) { target_phys_addr_t pa; pa = vq->vring.used + offsetof(VRingUsed, flags); stw_phys(pa, lduw_phys(pa) | mask); } static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask) { target_phys_addr_t pa; pa = vq->vring.used + offsetof(VRingUsed, flags); stw_phys(pa, lduw_phys(pa) & ~mask); } void virtio_queue_set_notification(VirtQueue *vq, int enable) { if (enable) vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY); else vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY); } int virtio_queue_ready(VirtQueue *vq) { return vq->vring.avail != 0; } int virtio_queue_empty(VirtQueue *vq) { return vring_avail_idx(vq) == vq->last_avail_idx; } void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem, unsigned int len, unsigned int idx) { unsigned int offset; int i; offset = 0; for (i = 0; i < elem->in_num; i++) { size_t size = MIN(len - offset, elem->in_sg[i].iov_len); cpu_physical_memory_unmap(elem->in_sg[i].iov_base, elem->in_sg[i].iov_len, 1, size); offset += elem->in_sg[i].iov_len; } for (i = 0; i < elem->out_num; i++) cpu_physical_memory_unmap(elem->out_sg[i].iov_base, elem->out_sg[i].iov_len, 0, elem->out_sg[i].iov_len); idx = (idx + vring_used_idx(vq)) % vq->vring.num; /* Get a pointer to the next entry in the used ring. */ vring_used_ring_id(vq, idx, elem->index); vring_used_ring_len(vq, idx, len); } void virtqueue_flush(VirtQueue *vq, unsigned int count) { /* Make sure buffer is written before we update index. */ wmb(); vring_used_idx_increment(vq, count); vq->inuse -= count; } void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem, unsigned int len) { virtqueue_fill(vq, elem, len, 0); virtqueue_flush(vq, 1); } static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx) { uint16_t num_heads = vring_avail_idx(vq) - idx; /* Check it isn't doing very strange things with descriptor numbers. */ if (num_heads > vq->vring.num) { fprintf(stderr, "Guest moved used index from %u to %u", idx, vring_avail_idx(vq)); exit(1); } return num_heads; } static unsigned int virtqueue_get_head(VirtQueue *vq, unsigned int idx) { unsigned int head; /* Grab the next descriptor number they're advertising, and increment * the index we've seen. */ head = vring_avail_ring(vq, idx % vq->vring.num); /* If their number is silly, that's a fatal mistake. */ if (head >= vq->vring.num) { fprintf(stderr, "Guest says index %u is available", head); exit(1); } return head; } static unsigned virtqueue_next_desc(target_phys_addr_t desc_pa, unsigned int i, unsigned int max) { unsigned int next; /* If this descriptor says it doesn't chain, we're done. */ if (!(vring_desc_flags(desc_pa, i) & VRING_DESC_F_NEXT)) return max; /* Check they're not leading us off end of descriptors. */ next = vring_desc_next(desc_pa, i); /* Make sure compiler knows to grab that: we don't want it changing! */ wmb(); if (next >= max) { fprintf(stderr, "Desc next is %u", next); exit(1); } return next; } int virtqueue_avail_bytes(VirtQueue *vq, int in_bytes, int out_bytes) { unsigned int idx; int total_bufs, in_total, out_total; idx = vq->last_avail_idx; total_bufs = in_total = out_total = 0; while (virtqueue_num_heads(vq, idx)) { unsigned int max, num_bufs, indirect = 0; target_phys_addr_t desc_pa; int i; max = vq->vring.num; num_bufs = total_bufs; i = virtqueue_get_head(vq, idx++); desc_pa = vq->vring.desc; if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_INDIRECT) { if (vring_desc_len(desc_pa, i) % sizeof(VRingDesc)) { fprintf(stderr, "Invalid size for indirect buffer table\n"); exit(1); } /* If we've got too many, that implies a descriptor loop. */ if (num_bufs >= max) { fprintf(stderr, "Looped descriptor"); exit(1); } /* loop over the indirect descriptor table */ indirect = 1; max = vring_desc_len(desc_pa, i) / sizeof(VRingDesc); num_bufs = i = 0; desc_pa = vring_desc_addr(desc_pa, i); } do { /* If we've got too many, that implies a descriptor loop. */ if (++num_bufs > max) { fprintf(stderr, "Looped descriptor"); exit(1); } if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_WRITE) { if (in_bytes > 0 && (in_total += vring_desc_len(desc_pa, i)) >= in_bytes) return 1; } else { if (out_bytes > 0 && (out_total += vring_desc_len(desc_pa, i)) >= out_bytes) return 1; } } while ((i = virtqueue_next_desc(desc_pa, i, max)) != max); if (!indirect) total_bufs = num_bufs; else total_bufs++; } return 0; } int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem) { unsigned int i, head, max; target_phys_addr_t desc_pa = vq->vring.desc; target_phys_addr_t len; if (!virtqueue_num_heads(vq, vq->last_avail_idx)) return 0; /* When we start there are none of either input nor output. */ elem->out_num = elem->in_num = 0; max = vq->vring.num; i = head = virtqueue_get_head(vq, vq->last_avail_idx++); if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_INDIRECT) { if (vring_desc_len(desc_pa, i) % sizeof(VRingDesc)) { fprintf(stderr, "Invalid size for indirect buffer table\n"); exit(1); } /* loop over the indirect descriptor table */ max = vring_desc_len(desc_pa, i) / sizeof(VRingDesc); desc_pa = vring_desc_addr(desc_pa, i); i = 0; } do { struct iovec *sg; int is_write = 0; if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_WRITE) { elem->in_addr[elem->in_num] = vring_desc_addr(desc_pa, i); sg = &elem->in_sg[elem->in_num++]; is_write = 1; } else sg = &elem->out_sg[elem->out_num++]; /* Grab the first descriptor, and check it's OK. */ sg->iov_len = vring_desc_len(desc_pa, i); len = sg->iov_len; sg->iov_base = cpu_physical_memory_map(vring_desc_addr(desc_pa, i), &len, is_write); if (sg->iov_base == NULL || len != sg->iov_len) { fprintf(stderr, "virtio: trying to map MMIO memory\n"); exit(1); } /* If we've got too many, that implies a descriptor loop. */ if ((elem->in_num + elem->out_num) > max) { fprintf(stderr, "Looped descriptor"); exit(1); } } while ((i = virtqueue_next_desc(desc_pa, i, max)) != max); elem->index = head; vq->inuse++; return elem->in_num + elem->out_num; } /* virtio device */ static void virtio_notify_vector(VirtIODevice *vdev, uint16_t vector) { if (vdev->binding->notify) { vdev->binding->notify(vdev->binding_opaque, vector); } } void virtio_update_irq(VirtIODevice *vdev) { virtio_notify_vector(vdev, VIRTIO_NO_VECTOR); } void virtio_reset(void *opaque) { VirtIODevice *vdev = opaque; int i; if (vdev->reset) vdev->reset(vdev); vdev->guest_features = 0; vdev->queue_sel = 0; vdev->status = 0; vdev->isr = 0; vdev->config_vector = VIRTIO_NO_VECTOR; virtio_notify_vector(vdev, vdev->config_vector); for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) { vdev->vq[i].vring.desc = 0; vdev->vq[i].vring.avail = 0; vdev->vq[i].vring.used = 0; vdev->vq[i].last_avail_idx = 0; vdev->vq[i].pa = 0; vdev->vq[i].vector = VIRTIO_NO_VECTOR; } } uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr) { uint8_t val; vdev->get_config(vdev, vdev->config); if (addr > (vdev->config_len - sizeof(val))) return (uint32_t)-1; memcpy(&val, vdev->config + addr, sizeof(val)); return val; } uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr) { uint16_t val; vdev->get_config(vdev, vdev->config); if (addr > (vdev->config_len - sizeof(val))) return (uint32_t)-1; memcpy(&val, vdev->config + addr, sizeof(val)); return val; } uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr) { uint32_t val; vdev->get_config(vdev, vdev->config); if (addr > (vdev->config_len - sizeof(val))) return (uint32_t)-1; memcpy(&val, vdev->config + addr, sizeof(val)); return val; } void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data) { uint8_t val = data; if (addr > (vdev->config_len - sizeof(val))) return; memcpy(vdev->config + addr, &val, sizeof(val)); if (vdev->set_config) vdev->set_config(vdev, vdev->config); } void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data) { uint16_t val = data; if (addr > (vdev->config_len - sizeof(val))) return; memcpy(vdev->config + addr, &val, sizeof(val)); if (vdev->set_config) vdev->set_config(vdev, vdev->config); } void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data) { uint32_t val = data; if (addr > (vdev->config_len - sizeof(val))) return; memcpy(vdev->config + addr, &val, sizeof(val)); if (vdev->set_config) vdev->set_config(vdev, vdev->config); } void virtio_queue_set_addr(VirtIODevice *vdev, int n, target_phys_addr_t addr) { vdev->vq[n].pa = addr; virtqueue_init(&vdev->vq[n]); } target_phys_addr_t virtio_queue_get_addr(VirtIODevice *vdev, int n) { return vdev->vq[n].pa; } int virtio_queue_get_num(VirtIODevice *vdev, int n) { return vdev->vq[n].vring.num; } void virtio_queue_notify(VirtIODevice *vdev, int n) { if (n < VIRTIO_PCI_QUEUE_MAX && vdev->vq[n].vring.desc) { vdev->vq[n].handle_output(vdev, &vdev->vq[n]); } } uint16_t virtio_queue_vector(VirtIODevice *vdev, int n) { return n < VIRTIO_PCI_QUEUE_MAX ? vdev->vq[n].vector : VIRTIO_NO_VECTOR; } void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector) { if (n < VIRTIO_PCI_QUEUE_MAX) vdev->vq[n].vector = vector; } VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size, void (*handle_output)(VirtIODevice *, VirtQueue *)) { int i; for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) { if (vdev->vq[i].vring.num == 0) break; } if (i == VIRTIO_PCI_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE) abort(); vdev->vq[i].vring.num = queue_size; vdev->vq[i].handle_output = handle_output; return &vdev->vq[i]; } void virtio_irq(VirtQueue *vq) { vq->vdev->isr |= 0x01; virtio_notify_vector(vq->vdev, vq->vector); } void virtio_notify(VirtIODevice *vdev, VirtQueue *vq) { /* Always notify when queue is empty (when feature acknowledge) */ if ((vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT) && (!(vdev->guest_features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) || (vq->inuse || vring_avail_idx(vq) != vq->last_avail_idx))) return; vdev->isr |= 0x01; virtio_notify_vector(vdev, vq->vector); } void virtio_notify_config(VirtIODevice *vdev) { if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) return; vdev->isr |= 0x03; virtio_notify_vector(vdev, vdev->config_vector); } void virtio_save(VirtIODevice *vdev, QEMUFile *f) { int i; if (vdev->binding->save_config) vdev->binding->save_config(vdev->binding_opaque, f); qemu_put_8s(f, &vdev->status); qemu_put_8s(f, &vdev->isr); qemu_put_be16s(f, &vdev->queue_sel); qemu_put_be32s(f, &vdev->guest_features); qemu_put_be32(f, vdev->config_len); qemu_put_buffer(f, vdev->config, vdev->config_len); for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) { if (vdev->vq[i].vring.num == 0) break; } qemu_put_be32(f, i); for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) { if (vdev->vq[i].vring.num == 0) break; qemu_put_be32(f, vdev->vq[i].vring.num); qemu_put_be64(f, vdev->vq[i].pa); qemu_put_be16s(f, &vdev->vq[i].last_avail_idx); if (vdev->binding->save_queue) vdev->binding->save_queue(vdev->binding_opaque, i, f); } } int virtio_load(VirtIODevice *vdev, QEMUFile *f) { int num, i, ret; uint32_t features; uint32_t supported_features = vdev->binding->get_features(vdev->binding_opaque); if (vdev->binding->load_config) { ret = vdev->binding->load_config(vdev->binding_opaque, f); if (ret) return ret; } qemu_get_8s(f, &vdev->status); qemu_get_8s(f, &vdev->isr); qemu_get_be16s(f, &vdev->queue_sel); qemu_get_be32s(f, &features); if (features & ~supported_features) { fprintf(stderr, "Features 0x%x unsupported. Allowed features: 0x%x\n", features, supported_features); return -1; } vdev->guest_features = features; vdev->config_len = qemu_get_be32(f); qemu_get_buffer(f, vdev->config, vdev->config_len); num = qemu_get_be32(f); for (i = 0; i < num; i++) { vdev->vq[i].vring.num = qemu_get_be32(f); vdev->vq[i].pa = qemu_get_be64(f); qemu_get_be16s(f, &vdev->vq[i].last_avail_idx); if (vdev->vq[i].pa) { virtqueue_init(&vdev->vq[i]); } if (vdev->binding->load_queue) { ret = vdev->binding->load_queue(vdev->binding_opaque, i, f); if (ret) return ret; } } virtio_notify_vector(vdev, VIRTIO_NO_VECTOR); return 0; } void virtio_cleanup(VirtIODevice *vdev) { if (vdev->config) qemu_free(vdev->config); qemu_free(vdev->vq); } VirtIODevice *virtio_common_init(const char *name, uint16_t device_id, size_t config_size, size_t struct_size) { VirtIODevice *vdev; int i; vdev = qemu_mallocz(struct_size); vdev->device_id = device_id; vdev->status = 0; vdev->isr = 0; vdev->queue_sel = 0; vdev->config_vector = VIRTIO_NO_VECTOR; vdev->vq = qemu_mallocz(sizeof(VirtQueue) * VIRTIO_PCI_QUEUE_MAX); for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) { vdev->vq[i].vector = VIRTIO_NO_VECTOR; vdev->vq[i].vdev = vdev; } vdev->name = name; vdev->config_len = config_size; if (vdev->config_len) vdev->config = qemu_mallocz(config_size); else vdev->config = NULL; return vdev; } void virtio_bind_device(VirtIODevice *vdev, const VirtIOBindings *binding, void *opaque) { vdev->binding = binding; vdev->binding_opaque = opaque; } target_phys_addr_t virtio_queue_get_desc_addr(VirtIODevice *vdev, int n) { return vdev->vq[n].vring.desc; } target_phys_addr_t virtio_queue_get_avail_addr(VirtIODevice *vdev, int n) { return vdev->vq[n].vring.avail; } target_phys_addr_t virtio_queue_get_used_addr(VirtIODevice *vdev, int n) { return vdev->vq[n].vring.used; } target_phys_addr_t virtio_queue_get_ring_addr(VirtIODevice *vdev, int n) { return vdev->vq[n].vring.desc; } target_phys_addr_t virtio_queue_get_desc_size(VirtIODevice *vdev, int n) { return sizeof(VRingDesc) * vdev->vq[n].vring.num; } target_phys_addr_t virtio_queue_get_avail_size(VirtIODevice *vdev, int n) { return offsetof(VRingAvail, ring) + sizeof(uint64_t) * vdev->vq[n].vring.num; } target_phys_addr_t virtio_queue_get_used_size(VirtIODevice *vdev, int n) { return offsetof(VRingUsed, ring) + sizeof(VRingUsedElem) * vdev->vq[n].vring.num; } target_phys_addr_t virtio_queue_get_ring_size(VirtIODevice *vdev, int n) { return vdev->vq[n].vring.used - vdev->vq[n].vring.desc + virtio_queue_get_used_size(vdev, n); } uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n) { return vdev->vq[n].last_avail_idx; } void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx) { vdev->vq[n].last_avail_idx = idx; } VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n) { return vdev->vq + n; } EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq) { return &vq->guest_notifier; } EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq) { return &vq->host_notifier; }