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libvhost-user: Support tracking inflight I/O in shared memory 

This patch adds support for VHOST_USER_GET_INFLIGHT_FD and
VHOST_USER_SET_INFLIGHT_FD message to set/get shared buffer
to/from qemu. Then backend can track inflight I/O in this buffer.

Signed-off-by: Xie Yongji <xieyongji@baidu.com>
Signed-off-by: Zhang Yu <zhangyu31@baidu.com>
Message-Id: <20190228085355.9614-5-xieyongji@baidu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Xie Yongji 2019-02-28 16:53:52 +08:00 committed by Michael S. Tsirkin
parent f7671f3d49
commit 5f9ff1eff3
3 changed files with 400 additions and 21 deletions
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2
Makefile
View File

@ -497,7 +497,7 @@ Makefile: $(version-obj-y)
# Build libraries
libqemuutil.a: $(util-obj-y) $(trace-obj-y) $(stub-obj-y)
libvhost-user.a: $(libvhost-user-obj-y)
libvhost-user.a: $(libvhost-user-obj-y) $(util-obj-y) $(stub-obj-y)
######################################################################

349
contrib/libvhost-user/libvhost-user.c
View File

@ -41,6 +41,8 @@
#endif
#include "qemu/atomic.h"
#include "qemu/osdep.h"
#include "qemu/memfd.h"
#include "libvhost-user.h"
@ -53,6 +55,18 @@
_min1 < _min2 ? _min1 : _min2; })
#endif
/* Round number down to multiple */
#define ALIGN_DOWN(n, m) ((n) / (m) * (m))
/* Round number up to multiple */
#define ALIGN_UP(n, m) ALIGN_DOWN((n) + (m) - 1, (m))
/* Align each region to cache line size in inflight buffer */
#define INFLIGHT_ALIGNMENT 64
/* The version of inflight buffer */
#define INFLIGHT_VERSION 1
#define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64)
/* The version of the protocol we support */
@ -66,6 +80,20 @@
} \
} while (0)
static inline
bool has_feature(uint64_t features, unsigned int fbit)
{
assert(fbit < 64);
return !!(features & (1ULL << fbit));
}
static inline
bool vu_has_feature(VuDev *dev,
unsigned int fbit)
{
return has_feature(dev->features, fbit);
}
static const char *
vu_request_to_string(unsigned int req)
{
@ -100,6 +128,8 @@ vu_request_to_string(unsigned int req)
REQ(VHOST_USER_POSTCOPY_ADVISE),
REQ(VHOST_USER_POSTCOPY_LISTEN),
REQ(VHOST_USER_POSTCOPY_END),
REQ(VHOST_USER_GET_INFLIGHT_FD),
REQ(VHOST_USER_SET_INFLIGHT_FD),
REQ(VHOST_USER_MAX),
};
#undef REQ
@ -890,6 +920,91 @@ vu_check_queue_msg_file(VuDev *dev, VhostUserMsg *vmsg)
return true;
}
static int
inflight_desc_compare(const void *a, const void *b)
{
VuVirtqInflightDesc *desc0 = (VuVirtqInflightDesc *)a,
*desc1 = (VuVirtqInflightDesc *)b;
if (desc1->counter > desc0->counter &&
(desc1->counter - desc0->counter) < VIRTQUEUE_MAX_SIZE * 2) {
return 1;
}
return -1;
}
static int
vu_check_queue_inflights(VuDev *dev, VuVirtq *vq)
{
int i = 0;
if (!has_feature(dev->protocol_features,
VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)) {
return 0;
}
if (unlikely(!vq->inflight)) {
return -1;
}
if (unlikely(!vq->inflight->version)) {
/* initialize the buffer */
vq->inflight->version = INFLIGHT_VERSION;
return 0;
}
vq->used_idx = vq->vring.used->idx;
vq->resubmit_num = 0;
vq->resubmit_list = NULL;
vq->counter = 0;
if (unlikely(vq->inflight->used_idx != vq->used_idx)) {
vq->inflight->desc[vq->inflight->last_batch_head].inflight = 0;
barrier();
vq->inflight->used_idx = vq->used_idx;
}
for (i = 0; i < vq->inflight->desc_num; i++) {
if (vq->inflight->desc[i].inflight == 1) {
vq->inuse++;
}
}
vq->shadow_avail_idx = vq->last_avail_idx = vq->inuse + vq->used_idx;
if (vq->inuse) {
vq->resubmit_list = malloc(sizeof(VuVirtqInflightDesc) * vq->inuse);
if (!vq->resubmit_list) {
return -1;
}
for (i = 0; i < vq->inflight->desc_num; i++) {
if (vq->inflight->desc[i].inflight) {
vq->resubmit_list[vq->resubmit_num].index = i;
vq->resubmit_list[vq->resubmit_num].counter =
vq->inflight->desc[i].counter;
vq->resubmit_num++;
}
}
if (vq->resubmit_num > 1) {
qsort(vq->resubmit_list, vq->resubmit_num,
sizeof(VuVirtqInflightDesc), inflight_desc_compare);
}
vq->counter = vq->resubmit_list[0].counter + 1;
}
/* in case of I/O hang after reconnecting */
if (eventfd_write(vq->kick_fd, 1)) {
return -1;
}
return 0;
}
static bool
vu_set_vring_kick_exec(VuDev *dev, VhostUserMsg *vmsg)
{
@ -923,6 +1038,10 @@ vu_set_vring_kick_exec(VuDev *dev, VhostUserMsg *vmsg)
dev->vq[index].kick_fd, index);
}
if (vu_check_queue_inflights(dev, &dev->vq[index])) {
vu_panic(dev, "Failed to check inflights for vq: %d\n", index);
}
return false;
}
@ -995,6 +1114,11 @@ vu_set_vring_call_exec(VuDev *dev, VhostUserMsg *vmsg)
dev->vq[index].call_fd = vmsg->fds[0];
/* in case of I/O hang after reconnecting */
if (eventfd_write(vmsg->fds[0], 1)) {
return -1;
}
DPRINT("Got call_fd: %d for vq: %d\n", vmsg->fds[0], index);
return false;
@ -1209,6 +1333,116 @@ vu_set_postcopy_end(VuDev *dev, VhostUserMsg *vmsg)
return true;
}
static inline uint64_t
vu_inflight_queue_size(uint16_t queue_size)
{
return ALIGN_UP(sizeof(VuDescStateSplit) * queue_size +
sizeof(uint16_t), INFLIGHT_ALIGNMENT);
}
static bool
vu_get_inflight_fd(VuDev *dev, VhostUserMsg *vmsg)
{
int fd;
void *addr;
uint64_t mmap_size;
uint16_t num_queues, queue_size;
if (vmsg->size != sizeof(vmsg->payload.inflight)) {
vu_panic(dev, "Invalid get_inflight_fd message:%d", vmsg->size);
vmsg->payload.inflight.mmap_size = 0;
return true;
}
num_queues = vmsg->payload.inflight.num_queues;
queue_size = vmsg->payload.inflight.queue_size;
DPRINT("set_inflight_fd num_queues: %"PRId16"\n", num_queues);
DPRINT("set_inflight_fd queue_size: %"PRId16"\n", queue_size);
mmap_size = vu_inflight_queue_size(queue_size) * num_queues;
addr = qemu_memfd_alloc("vhost-inflight", mmap_size,
F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL,
&fd, NULL);
if (!addr) {
vu_panic(dev, "Failed to alloc vhost inflight area");
vmsg->payload.inflight.mmap_size = 0;
return true;
}
memset(addr, 0, mmap_size);
dev->inflight_info.addr = addr;
dev->inflight_info.size = vmsg->payload.inflight.mmap_size = mmap_size;
dev->inflight_info.fd = vmsg->fds[0] = fd;
vmsg->fd_num = 1;
vmsg->payload.inflight.mmap_offset = 0;
DPRINT("send inflight mmap_size: %"PRId64"\n",
vmsg->payload.inflight.mmap_size);
DPRINT("send inflight mmap offset: %"PRId64"\n",
vmsg->payload.inflight.mmap_offset);
return true;
}
static bool
vu_set_inflight_fd(VuDev *dev, VhostUserMsg *vmsg)
{
int fd, i;
uint64_t mmap_size, mmap_offset;
uint16_t num_queues, queue_size;
void *rc;
if (vmsg->fd_num != 1 ||
vmsg->size != sizeof(vmsg->payload.inflight)) {
vu_panic(dev, "Invalid set_inflight_fd message size:%d fds:%d",
vmsg->size, vmsg->fd_num);
return false;
}
fd = vmsg->fds[0];
mmap_size = vmsg->payload.inflight.mmap_size;
mmap_offset = vmsg->payload.inflight.mmap_offset;
num_queues = vmsg->payload.inflight.num_queues;
queue_size = vmsg->payload.inflight.queue_size;
DPRINT("set_inflight_fd mmap_size: %"PRId64"\n", mmap_size);
DPRINT("set_inflight_fd mmap_offset: %"PRId64"\n", mmap_offset);
DPRINT("set_inflight_fd num_queues: %"PRId16"\n", num_queues);
DPRINT("set_inflight_fd queue_size: %"PRId16"\n", queue_size);
rc = mmap(0, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED,
fd, mmap_offset);
if (rc == MAP_FAILED) {
vu_panic(dev, "set_inflight_fd mmap error: %s", strerror(errno));
return false;
}
if (dev->inflight_info.fd) {
close(dev->inflight_info.fd);
}
if (dev->inflight_info.addr) {
munmap(dev->inflight_info.addr, dev->inflight_info.size);
}
dev->inflight_info.fd = fd;
dev->inflight_info.addr = rc;
dev->inflight_info.size = mmap_size;
for (i = 0; i < num_queues; i++) {
dev->vq[i].inflight = (VuVirtqInflight *)rc;
dev->vq[i].inflight->desc_num = queue_size;
rc = (void *)((char *)rc + vu_inflight_queue_size(queue_size));
}
return false;
}
static bool
vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
{
@ -1287,6 +1521,10 @@ vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
return vu_set_postcopy_listen(dev, vmsg);
case VHOST_USER_POSTCOPY_END:
return vu_set_postcopy_end(dev, vmsg);
case VHOST_USER_GET_INFLIGHT_FD:
return vu_get_inflight_fd(dev, vmsg);
case VHOST_USER_SET_INFLIGHT_FD:
return vu_set_inflight_fd(dev, vmsg);
default:
vmsg_close_fds(vmsg);
vu_panic(dev, "Unhandled request: %d", vmsg->request);
@ -1354,8 +1592,24 @@ vu_deinit(VuDev *dev)
close(vq->err_fd);
vq->err_fd = -1;
}
if (vq->resubmit_list) {
free(vq->resubmit_list);
vq->resubmit_list = NULL;
}
vq->inflight = NULL;
}
if (dev->inflight_info.addr) {
munmap(dev->inflight_info.addr, dev->inflight_info.size);
dev->inflight_info.addr = NULL;
}
if (dev->inflight_info.fd > 0) {
close(dev->inflight_info.fd);
dev->inflight_info.fd = -1;
}
vu_close_log(dev);
if (dev->slave_fd != -1) {
@ -1682,20 +1936,6 @@ vu_queue_empty(VuDev *dev, VuVirtq *vq)
return vring_avail_idx(vq) == vq->last_avail_idx;
}
static inline
bool has_feature(uint64_t features, unsigned int fbit)
{
assert(fbit < 64);
return !!(features & (1ULL << fbit));
}
static inline
bool vu_has_feature(VuDev *dev,
unsigned int fbit)
{
return has_feature(dev->features, fbit);
}
static bool
vring_notify(VuDev *dev, VuVirtq *vq)
{
@ -1824,12 +2064,6 @@ virtqueue_map_desc(VuDev *dev,
*p_num_sg = num_sg;
}
/* Round number down to multiple */
#define ALIGN_DOWN(n, m) ((n) / (m) * (m))
/* Round number up to multiple */
#define ALIGN_UP(n, m) ALIGN_DOWN((n) + (m) - 1, (m))
static void *
virtqueue_alloc_element(size_t sz,
unsigned out_num, unsigned in_num)
@ -1930,9 +2164,68 @@ vu_queue_map_desc(VuDev *dev, VuVirtq *vq, unsigned int idx, size_t sz)
return elem;
}
static int
vu_queue_inflight_get(VuDev *dev, VuVirtq *vq, int desc_idx)
{
if (!has_feature(dev->protocol_features,
VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)) {
return 0;
}
if (unlikely(!vq->inflight)) {
return -1;
}
vq->inflight->desc[desc_idx].counter = vq->counter++;
vq->inflight->desc[desc_idx].inflight = 1;
return 0;
}
static int
vu_queue_inflight_pre_put(VuDev *dev, VuVirtq *vq, int desc_idx)
{
if (!has_feature(dev->protocol_features,
VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)) {
return 0;
}
if (unlikely(!vq->inflight)) {
return -1;
}
vq->inflight->last_batch_head = desc_idx;
return 0;
}
static int
vu_queue_inflight_post_put(VuDev *dev, VuVirtq *vq, int desc_idx)
{
if (!has_feature(dev->protocol_features,
VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)) {
return 0;
}
if (unlikely(!vq->inflight)) {
return -1;
}
barrier();
vq->inflight->desc[desc_idx].inflight = 0;
barrier();
vq->inflight->used_idx = vq->used_idx;
return 0;
}
void *
vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz)
{
int i;
unsigned int head;
VuVirtqElement *elem;
@ -1941,6 +2234,18 @@ vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz)
return NULL;
}
if (unlikely(vq->resubmit_list && vq->resubmit_num > 0)) {
i = (--vq->resubmit_num);
elem = vu_queue_map_desc(dev, vq, vq->resubmit_list[i].index, sz);
if (!vq->resubmit_num) {
free(vq->resubmit_list);
vq->resubmit_list = NULL;
}
return elem;
}
if (vu_queue_empty(dev, vq)) {
return NULL;
}
@ -1971,6 +2276,8 @@ vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz)
vq->inuse++;
vu_queue_inflight_get(dev, vq, head);
return elem;
}
@ -2131,5 +2438,7 @@ vu_queue_push(VuDev *dev, VuVirtq *vq,
const VuVirtqElement *elem, unsigned int len)
{
vu_queue_fill(dev, vq, elem, len, 0);
vu_queue_inflight_pre_put(dev, vq, elem->index);
vu_queue_flush(dev, vq, 1);
vu_queue_inflight_post_put(dev, vq, elem->index);
}

70
contrib/libvhost-user/libvhost-user.h
View File

@ -53,6 +53,7 @@ enum VhostUserProtocolFeature {
VHOST_USER_PROTOCOL_F_CONFIG = 9,
VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD = 10,
VHOST_USER_PROTOCOL_F_HOST_NOTIFIER = 11,
VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD = 12,
VHOST_USER_PROTOCOL_F_MAX
};
@ -91,6 +92,8 @@ typedef enum VhostUserRequest {
VHOST_USER_POSTCOPY_ADVISE = 28,
VHOST_USER_POSTCOPY_LISTEN = 29,
VHOST_USER_POSTCOPY_END = 30,
VHOST_USER_GET_INFLIGHT_FD = 31,
VHOST_USER_SET_INFLIGHT_FD = 32,
VHOST_USER_MAX
} VhostUserRequest;
@ -138,6 +141,13 @@ typedef struct VhostUserVringArea {
uint64_t offset;
} VhostUserVringArea;
typedef struct VhostUserInflight {
uint64_t mmap_size;
uint64_t mmap_offset;
uint16_t num_queues;
uint16_t queue_size;
} VhostUserInflight;
#if defined(_WIN32)
# define VU_PACKED __attribute__((gcc_struct, packed))
#else
@ -163,6 +173,7 @@ typedef struct VhostUserMsg {
VhostUserLog log;
VhostUserConfig config;
VhostUserVringArea area;
VhostUserInflight inflight;
} payload;
int fds[VHOST_MEMORY_MAX_NREGIONS];
@ -234,9 +245,61 @@ typedef struct VuRing {
uint32_t flags;
} VuRing;
typedef struct VuDescStateSplit {
/* Indicate whether this descriptor is inflight or not.
* Only available for head-descriptor. */
uint8_t inflight;
/* Padding */
uint8_t padding[5];
/* Maintain a list for the last batch of used descriptors.
* Only available when batching is used for submitting */
uint16_t next;
/* Used to preserve the order of fetching available descriptors.
* Only available for head-descriptor. */
uint64_t counter;
} VuDescStateSplit;
typedef struct VuVirtqInflight {
/* The feature flags of this region. Now it's initialized to 0. */
uint64_t features;
/* The version of this region. It's 1 currently.
* Zero value indicates a vm reset happened. */
uint16_t version;
/* The size of VuDescStateSplit array. It's equal to the virtqueue
* size. Slave could get it from queue size field of VhostUserInflight. */
uint16_t desc_num;
/* The head of list that track the last batch of used descriptors. */
uint16_t last_batch_head;
/* Storing the idx value of used ring */
uint16_t used_idx;
/* Used to track the state of each descriptor in descriptor table */
VuDescStateSplit desc[0];
} VuVirtqInflight;
typedef struct VuVirtqInflightDesc {
uint16_t index;
uint64_t counter;
} VuVirtqInflightDesc;
typedef struct VuVirtq {
VuRing vring;
VuVirtqInflight *inflight;
VuVirtqInflightDesc *resubmit_list;
uint16_t resubmit_num;
uint64_t counter;
/* Next head to pop */
uint16_t last_avail_idx;
@ -279,11 +342,18 @@ typedef void (*vu_set_watch_cb) (VuDev *dev, int fd, int condition,
vu_watch_cb cb, void *data);
typedef void (*vu_remove_watch_cb) (VuDev *dev, int fd);
typedef struct VuDevInflightInfo {
int fd;
void *addr;
uint64_t size;
} VuDevInflightInfo;
struct VuDev {
int sock;
uint32_t nregions;
VuDevRegion regions[VHOST_MEMORY_MAX_NREGIONS];
VuVirtq vq[VHOST_MAX_NR_VIRTQUEUE];
VuDevInflightInfo inflight_info;
int log_call_fd;
int slave_fd;
uint64_t log_size;