From: Xie Yongji <xieyon...@baidu.com>
This patch introduces two new messages VHOST_USER_GET_INFLIGHT_FD
and VHOST_USER_SET_INFLIGHT_FD to support transferring a shared
buffer between qemu and backend.
Firstly, qemu uses VHOST_USER_GET_INFLIGHT_FD to get the
shared buffer from backend. Then qemu should send it back
through VHOST_USER_SET_INFLIGHT_FD each time we start vhost-user.
This shared buffer is used to track inflight I/O by backend.
Qemu should clear it when vm reset.
Signed-off-by: Xie Yongji <xieyon...@baidu.com>
Signed-off-by: Chai Wen <chai...@baidu.com>
Signed-off-by: Zhang Yu <zhangy...@baidu.com>
---
docs/interop/vhost-user.txt | 60 +++++++++++++++++
hw/virtio/vhost-user.c | 108 ++++++++++++++++++++++++++++++
hw/virtio/vhost.c | 108 ++++++++++++++++++++++++++++++
include/hw/virtio/vhost-backend.h | 9 +++
include/hw/virtio/vhost.h | 19 ++++++
5 files changed, 304 insertions(+)
diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt
index c2194711d9..67da41fdd2 100644
--- a/docs/interop/vhost-user.txt
+++ b/docs/interop/vhost-user.txt
@@ -142,6 +142,18 @@ Depending on the request type, payload can be:
Offset: a 64-bit offset of this area from the start of the
supplied file descriptor
+ * Inflight description
+ ----------------------------------------------------------
+ | mmap size | mmap offset | align | num queues | version |
+ ----------------------------------------------------------
+
+ mmap size: a 64-bit size of area to track inflight I/O
+ mmap offset: a 64-bit offset of this area from the start
+ of the supplied file descriptor
+ align: a 32-bit align of each region in this area
+ num queues: a 16-bit number of virtqueues
+ version: a 16-bit version of this area
+
In QEMU the vhost-user message is implemented with the following struct:
typedef struct VhostUserMsg {
@@ -157,6 +169,7 @@ typedef struct VhostUserMsg {
struct vhost_iotlb_msg iotlb;
VhostUserConfig config;
VhostUserVringArea area;
+ VhostUserInflight inflight;
};
} QEMU_PACKED VhostUserMsg;
@@ -175,6 +188,7 @@ the ones that do:
* VHOST_USER_GET_PROTOCOL_FEATURES
* VHOST_USER_GET_VRING_BASE
* VHOST_USER_SET_LOG_BASE (if VHOST_USER_PROTOCOL_F_LOG_SHMFD)
+ * VHOST_USER_GET_INFLIGHT_FD (if VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)
[ Also see the section on REPLY_ACK protocol extension. ]
@@ -188,6 +202,7 @@ in the ancillary data:
* VHOST_USER_SET_VRING_CALL
* VHOST_USER_SET_VRING_ERR
* VHOST_USER_SET_SLAVE_REQ_FD
+ * VHOST_USER_SET_INFLIGHT_FD (if VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)
If Master is unable to send the full message or receives a wrong reply it will
close the connection. An optional reconnection mechanism can be implemented.
@@ -382,6 +397,30 @@ If VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD protocol feature is
negotiated,
slave can send file descriptors (at most 8 descriptors in each message)
to master via ancillary data using this fd communication channel.
+Inflight I/O tracking
+---------------------
+
+To support slave reconnecting, slave need to track inflight I/O in a
+shared memory. VHOST_USER_GET_INFLIGHT_FD and VHOST_USER_SET_INFLIGHT_FD
+are used to transfer the memory between master and slave. And to encourage
+consistency, we provide a recommended format for this memory:
+
+offset width description
+0x0 0x400 region for queue0
+0x400 0x400 region for queue1
+0x800 0x400 region for queue2
+... ... ...
+
+For each virtqueue, we have a 1024 bytes region. The region's format is like:
+
+offset width description
+0x0 0x1 descriptor 0 is in use or not
+0x1 0x1 descriptor 1 is in use or not
+0x2 0x1 descriptor 2 is in use or not
+... ... ...
+
+For each descriptor, we use one byte to specify whether it's in use or not.
+
Protocol features
-----------------
@@ -397,6 +436,7 @@ Protocol features
#define VHOST_USER_PROTOCOL_F_CONFIG 9
#define VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD 10
#define VHOST_USER_PROTOCOL_F_HOST_NOTIFIER 11
+#define VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD 12
Master message types
--------------------
@@ -761,6 +801,26 @@ Master message types
was previously sent.
The value returned is an error indication; 0 is success.
+ * VHOST_USER_GET_INFLIGHT_FD
+ Id: 31
+ Equivalent ioctl: N/A
+ Master payload: inflight description
+
+ When VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD protocol feature has been
+ successfully negotiated, this message is submitted by master to get
+ a shared memory from slave. The shared memory will be used to track
+ inflight I/O by slave. Master should clear it when vm reset.
+
+ * VHOST_USER_SET_INFLIGHT_FD
+ Id: 32
+ Equivalent ioctl: N/A
+ Master payload: inflight description
+
+ When VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD protocol feature has been
+ successfully negotiated, this message is submitted by master to send
+ the shared inflight buffer back to slave so that slave could get
+ inflight I/O after a crash or restart.
+
Slave message types
-------------------
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index e09bed0e4a..4d118c6e14 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -52,6 +52,7 @@ 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
};
@@ -89,6 +90,8 @@ 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;
@@ -147,6 +150,14 @@ typedef struct VhostUserVringArea {
uint64_t offset;
} VhostUserVringArea;
+typedef struct VhostUserInflight {
+ uint64_t mmap_size;
+ uint64_t mmap_offset;
+ uint32_t align;
+ uint16_t num_queues;
+ uint16_t version;
+} VhostUserInflight;
+
typedef struct {
VhostUserRequest request;
@@ -169,6 +180,7 @@ typedef union {
VhostUserConfig config;
VhostUserCryptoSession session;
VhostUserVringArea area;
+ VhostUserInflight inflight;
} VhostUserPayload;
typedef struct VhostUserMsg {
@@ -1739,6 +1751,100 @@ static bool vhost_user_mem_section_filter(struct
vhost_dev *dev,
return result;
}
+static int vhost_user_get_inflight_fd(struct vhost_dev *dev,
+ struct vhost_inflight *inflight)
+{
+ void *addr;
+ int fd;
+ struct vhost_user *u = dev->opaque;
+ CharBackend *chr = u->user->chr;
+ VhostUserMsg msg = {
+ .hdr.request = VHOST_USER_GET_INFLIGHT_FD,
+ .hdr.flags = VHOST_USER_VERSION,
+ .payload.inflight.num_queues = dev->nvqs,
+ .hdr.size = sizeof(msg.payload.inflight),
+ };
+
+ if (!virtio_has_feature(dev->protocol_features,
+ VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)) {
+ return 0;
+ }
+
+ if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
+ return -1;
+ }
+
+ if (vhost_user_read(dev, &msg) < 0) {
+ return -1;
+ }
+
+ if (msg.hdr.request != VHOST_USER_GET_INFLIGHT_FD) {
+ error_report("Received unexpected msg type. "
+ "Expected %d received %d",
+ VHOST_USER_GET_INFLIGHT_FD, msg.hdr.request);
+ return -1;
+ }
+
+ if (msg.hdr.size != sizeof(msg.payload.inflight)) {
+ error_report("Received bad msg size.");
+ return -1;
+ }
+
+ if (!msg.payload.inflight.mmap_size) {
+ return 0;
+ }
+
+ fd = qemu_chr_fe_get_msgfd(chr);
+ if (fd < 0) {
+ error_report("Failed to get mem fd");
+ return -1;
+ }
+
+ addr = mmap(0, msg.payload.inflight.mmap_size, PROT_READ | PROT_WRITE,
+ MAP_SHARED, fd, msg.payload.inflight.mmap_offset);
+
+ if (addr == MAP_FAILED) {
+ error_report("Failed to mmap mem fd");
+ close(fd);
+ return -1;
+ }
+
+ inflight->addr = addr;
+ inflight->fd = fd;
+ inflight->size = msg.payload.inflight.mmap_size;
+ inflight->offset = msg.payload.inflight.mmap_offset;
+ inflight->align = msg.payload.inflight.align;
+ inflight->version = msg.payload.inflight.version;
+
+ return 0;
+}
+
+static int vhost_user_set_inflight_fd(struct vhost_dev *dev,
+ struct vhost_inflight *inflight)
+{
+ VhostUserMsg msg = {
+ .hdr.request = VHOST_USER_SET_INFLIGHT_FD,
+ .hdr.flags = VHOST_USER_VERSION,
+ .payload.inflight.mmap_size = inflight->size,
+ .payload.inflight.mmap_offset = inflight->offset,
+ .payload.inflight.align = inflight->align,
+ .payload.inflight.num_queues = dev->nvqs,
+ .payload.inflight.version = inflight->version,
+ .hdr.size = sizeof(msg.payload.inflight),
+ };
+
+ if (!virtio_has_feature(dev->protocol_features,
+ VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)) {
+ return 0;
+ }
+
+ if (vhost_user_write(dev, &msg, &inflight->fd, 1) < 0) {
+ return -1;
+ }
+
+ return 0;
+}
+
VhostUserState *vhost_user_init(void)
{
VhostUserState *user = g_new0(struct VhostUserState, 1);
@@ -1790,4 +1896,6 @@ const VhostOps user_ops = {
.vhost_crypto_create_session = vhost_user_crypto_create_session,
.vhost_crypto_close_session = vhost_user_crypto_close_session,
.vhost_backend_mem_section_filter = vhost_user_mem_section_filter,
+ .vhost_get_inflight_fd = vhost_user_get_inflight_fd,
+ .vhost_set_inflight_fd = vhost_user_set_inflight_fd,
};
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 569c4053ea..730f436692 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1481,6 +1481,114 @@ void vhost_dev_set_config_notifier(struct vhost_dev
*hdev,
hdev->config_ops = ops;
}
+void vhost_dev_reset_inflight(struct vhost_inflight *inflight)
+{
+ if (inflight->addr) {
+ memset(inflight->addr, 0, inflight->size);
+ }
+}
+
+void vhost_dev_free_inflight(struct vhost_inflight *inflight)
+{
+ if (inflight->addr) {
+ qemu_memfd_free(inflight->addr, inflight->size, inflight->fd);
+ inflight->addr = NULL;
+ inflight->fd = -1;
+ }
+}
+
+static int vhost_dev_resize_inflight(struct vhost_inflight *inflight,
+ uint64_t new_size)
+{
+ Error *err = NULL;
+ int fd = -1;
+ void *addr = qemu_memfd_alloc("vhost-inflight", new_size,
+ F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL,
+ &fd, &err);
+
+ if (err) {
+ error_report_err(err);
+ return -1;
+ }
+
+ vhost_dev_free_inflight(inflight);
+ inflight->offset = 0;
+ inflight->addr = addr;
+ inflight->fd = fd;
+ inflight->size = new_size;
+
+ return 0;
+}
+
+void vhost_dev_save_inflight(struct vhost_inflight *inflight, QEMUFile *f)
+{
+ if (inflight->addr) {
+ qemu_put_be64(f, inflight->size);
+ qemu_put_be64(f, inflight->offset);
+ qemu_put_be32(f, inflight->align);
+ qemu_put_be16(f, inflight->version);
+ qemu_put_buffer(f, inflight->addr, inflight->size);
+ } else {
+ qemu_put_be64(f, 0);
+ }
+}
+
+int vhost_dev_load_inflight(struct vhost_inflight *inflight, QEMUFile *f)
+{
+ uint64_t size;
+
+ size = qemu_get_be64(f);
+ if (!size) {
+ return 0;
+ }
+
+ if (inflight->size != size) {
+ if (vhost_dev_resize_inflight(inflight, size)) {
+ return -1;
+ }
+ }
+ inflight->size = size;
+ inflight->offset = qemu_get_be64(f);
+ inflight->align = qemu_get_be32(f);
+ inflight->version = qemu_get_be16(f);
+
+ qemu_get_buffer(f, inflight->addr, size);
+
+ return 0;
+}
+
+int vhost_dev_set_inflight(struct vhost_dev *dev,
+ struct vhost_inflight *inflight)
+{
+ int r;
+
+ if (dev->vhost_ops->vhost_set_inflight_fd && inflight->addr) {
+ r = dev->vhost_ops->vhost_set_inflight_fd(dev, inflight);
+ if (r) {
+ VHOST_OPS_DEBUG("vhost_set_inflight_fd failed");
+ return -errno;
+ }
+ }
+
+ return 0;
+}
+
+int vhost_dev_get_inflight(struct vhost_dev *dev,
+ struct vhost_inflight *inflight)
+{
+ int r;
+
+ if (dev->vhost_ops->vhost_get_inflight_fd) {
+ r = dev->vhost_ops->vhost_get_inflight_fd(dev, inflight);
+ if (r) {
+ VHOST_OPS_DEBUG("vhost_get_inflight_fd failed");
+ return -errno;
+ }
+ }
+
+ return 0;
+}
+
/* Host notifiers must be enabled at this point. */
int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
{
diff --git a/include/hw/virtio/vhost-backend.h
b/include/hw/virtio/vhost-backend.h
index 81283ec50f..97676bd237 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -25,6 +25,7 @@ typedef enum VhostSetConfigType {
VHOST_SET_CONFIG_TYPE_MIGRATION = 1,
} VhostSetConfigType;
+struct vhost_inflight;
struct vhost_dev;
struct vhost_log;
struct vhost_memory;
@@ -104,6 +105,12 @@ typedef int (*vhost_crypto_close_session_op)(struct
vhost_dev *dev,
typedef bool (*vhost_backend_mem_section_filter_op)(struct vhost_dev *dev,
MemoryRegionSection *section);
+typedef int (*vhost_get_inflight_fd_op)(struct vhost_dev *dev,
+ struct vhost_inflight *inflight);
+
+typedef int (*vhost_set_inflight_fd_op)(struct vhost_dev *dev,
+ struct vhost_inflight *inflight);
+
typedef struct VhostOps {
VhostBackendType backend_type;
vhost_backend_init vhost_backend_init;
@@ -142,6 +149,8 @@ typedef struct VhostOps {
vhost_crypto_create_session_op vhost_crypto_create_session;
vhost_crypto_close_session_op vhost_crypto_close_session;
vhost_backend_mem_section_filter_op vhost_backend_mem_section_filter;
+ vhost_get_inflight_fd_op vhost_get_inflight_fd;
+ vhost_set_inflight_fd_op vhost_set_inflight_fd;
} VhostOps;
extern const VhostOps user_ops;
diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index a7f449fa87..0a71596d8b 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -7,6 +7,16 @@
#include "exec/memory.h"
/* Generic structures common for any vhost based device. */
+
+struct vhost_inflight {
+ int fd;
+ void *addr;
+ uint64_t size;
+ uint64_t offset;
+ uint32_t align;
+ uint16_t version;
+};
+
struct vhost_virtqueue {
int kick;
int call;
@@ -120,4 +130,13 @@ int vhost_dev_set_config(struct vhost_dev *dev, const
uint8_t *data,
*/
void vhost_dev_set_config_notifier(struct vhost_dev *dev,
const VhostDevConfigOps *ops);
+
+void vhost_dev_reset_inflight(struct vhost_inflight *inflight);
+void vhost_dev_free_inflight(struct vhost_inflight *inflight);
+void vhost_dev_save_inflight(struct vhost_inflight *inflight, QEMUFile *f);
+int vhost_dev_load_inflight(struct vhost_inflight *inflight, QEMUFile *f);
+int vhost_dev_set_inflight(struct vhost_dev *dev,
+ struct vhost_inflight *inflight);
+int vhost_dev_get_inflight(struct vhost_dev *dev,
+ struct vhost_inflight *inflight);
#endif
--
2.17.1
