[dpdk-dev] [PATCH v7 04/10] vhost: add two new messages to support a shared buffer

Yu, Jin jin.yu at intel.com
Thu Sep 26 17:06:22 CEST 2019


> -----Original Message-----
> From: Bie, Tiwei
> Sent: Thursday, September 26, 2019 3:39 PM
> To: Yu, Jin <jin.yu at intel.com>
> Cc: dev at dpdk.org; Liu, Changpeng <changpeng.liu at intel.com>;
> maxime.coquelin at redhat.com; Wang, Zhihong <zhihong.wang at intel.com>; Lin
> Li <lilin24 at baidu.com>; Xun Ni <nixun at baidu.com>; Yu Zhang
> <zhangyu31 at baidu.com>
> Subject: Re: [PATCH v7 04/10] vhost: add two new messages to support a shared
> buffer
> 
> On Fri, Sep 20, 2019 at 08:00:56PM +0800, Jin Yu wrote:
> > 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.
> >
> > Signed-off-by: Lin Li <lilin24 at baidu.com>
> > Signed-off-by: Xun Ni <nixun at baidu.com>
> > Signed-off-by: Yu Zhang <zhangyu31 at baidu.com>
> > Signed-off-by: Jin Yu <jin.yu at intel.com>
> > ---
> >  lib/librte_vhost/vhost.h      |   7 +
> >  lib/librte_vhost/vhost_user.c | 260 +++++++++++++++++++++++++++++++++-
> >  lib/librte_vhost/vhost_user.h |   4 +-
> >  3 files changed, 269 insertions(+), 2 deletions(-)
> >
> > diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h index
> > 884befa85..d67ba849a 100644
> > --- a/lib/librte_vhost/vhost.h
> > +++ b/lib/librte_vhost/vhost.h
> > @@ -286,6 +286,12 @@ struct guest_page {
> >  	uint64_t size;
> >  };
> >
> > +struct inflight_mem_info {
> > +	int		fd;
> > +	void		*addr;
> > +	uint64_t	size;
> > +};
> > +
> >  /**
> >   * Device structure contains all configuration information relating
> >   * to the device.
> > @@ -303,6 +309,7 @@ struct virtio_net {
> >  	uint32_t		nr_vring;
> >  	int			dequeue_zero_copy;
> >  	struct vhost_virtqueue	*virtqueue[VHOST_MAX_QUEUE_PAIRS * 2];
> > +	struct inflight_mem_info *inflight_info;
> >  #define IF_NAME_SZ (PATH_MAX > IFNAMSIZ ? PATH_MAX : IFNAMSIZ)
> >  	char			ifname[IF_NAME_SZ];
> >  	uint64_t		log_size;
> > diff --git a/lib/librte_vhost/vhost_user.c
> > b/lib/librte_vhost/vhost_user.c index c9e29ece8..66582a30f 100644
> > --- a/lib/librte_vhost/vhost_user.c
> > +++ b/lib/librte_vhost/vhost_user.c
> > @@ -37,6 +37,10 @@
> >  #ifdef RTE_LIBRTE_VHOST_POSTCOPY
> >  #include <linux/userfaultfd.h>
> >  #endif
> > +#ifdef F_ADD_SEALS /* if file sealing is supported, so is memfd */
> > +#include <linux/memfd.h> #define MEMFD_SUPPORTED #endif
> >
> >  #include <rte_common.h>
> >  #include <rte_malloc.h>
> > @@ -49,6 +53,15 @@
> >  #define VIRTIO_MIN_MTU 68
> >  #define VIRTIO_MAX_MTU 65535
> >
> > +#define INFLIGHT_ALIGNMENT	64
> > +#define INFLIGHT_VERSION	0xabcd
> 
> Why the version is 0xabcd? Shouldn't it be 1?
> 
> https://git.qemu.org/?p=qemu.git;a=blob;f=docs/interop/vhost-
> user.rst;h=7827b710aa0a223f6f184b229f4b5ced6420b638;hb=HEAD#l551
> https://git.qemu.org/?p=qemu.git;a=blob;f=docs/interop/vhost-
> user.rst;h=7827b710aa0a223f6f184b229f4b5ced6420b638;hb=HEAD#l658
Yeah, I didn't fix it. Will fix it in next version.
> 
> > +#define VIRTQUEUE_MAX_SIZE	1024
> > +
> > +#define CLOEXEC		0x0001U
> > +
> > +#define ALIGN_DOWN(n, m) ((n) / (m) * (m)) #define ALIGN_UP(n, m)
> > +ALIGN_DOWN((n) + (m) - 1, (m))
> > +
> >  static const char *vhost_message_str[VHOST_USER_MAX] = {
> >  	[VHOST_USER_NONE] = "VHOST_USER_NONE",
> >  	[VHOST_USER_GET_FEATURES] = "VHOST_USER_GET_FEATURES", @@
> -78,6
> > +91,8 @@ static const char *vhost_message_str[VHOST_USER_MAX] = {
> >  	[VHOST_USER_POSTCOPY_ADVISE]  =
> "VHOST_USER_POSTCOPY_ADVISE",
> >  	[VHOST_USER_POSTCOPY_LISTEN]  =
> "VHOST_USER_POSTCOPY_LISTEN",
> >  	[VHOST_USER_POSTCOPY_END]  = "VHOST_USER_POSTCOPY_END",
> > +	[VHOST_USER_GET_INFLIGHT_FD] = "VHOST_USER_GET_INFLIGHT_FD",
> > +	[VHOST_USER_SET_INFLIGHT_FD] = "VHOST_USER_SET_INFLIGHT_FD",
> >  };
> >
> >  static int send_vhost_reply(int sockfd, struct VhostUserMsg *msg); @@
> > -160,6 +175,21 @@ vhost_backend_cleanup(struct virtio_net *dev)
> >  		dev->log_addr = 0;
> >  	}
> >
> > +	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;
> > +	}
> > +
> > +	if (dev->inflight_info) {
> > +		free(dev->inflight_info);
> > +		dev->inflight_info = NULL;
> > +	}
> 
> You should check dev->inflight_info first before dereferencing it.
Got it. Thanks.
> 
> > +
> >  	if (dev->slave_req_fd >= 0) {
> >  		close(dev->slave_req_fd);
> >  		dev->slave_req_fd = -1;
> > @@ -1165,6 +1195,233 @@ virtio_is_ready(struct virtio_net *dev)
> >  	return 1;
> >  }
> >
> > +static int
> > +mem_create(const char *name, unsigned int flags) { #ifdef
> > +MEMFD_SUPPORTED
> > +	return memfd_create(name, flags);
> > +#else
> > +	RTE_LOG(ERR, VHOST_CONFIG,
> > +		"doesn't support memfd--name:%s and flag:%x\n",
> > +		name, flags);
> 
> You probably don't want to always print an error when memfd isn't available.
I saw below error message from ci/Intel-compilation. 
../lib/librte_vhost/vhost_user.c:1202:24: error: unused parameter ‘name’ [-Werror=unused-parameter]
 mem_create(const char *name, unsigned int flags)
                        ^~~~
../lib/librte_vhost/vhost_user.c:1202:43: error: unused parameter ‘flags’ [-Werror=unused-parameter]
 mem_create(const char *name, unsigned int flags)

That's why I add this print.Should I ignore this?
Thanks.

> 
> > +	return -1;
> > +#endif
> > +}
> > +
> > +static void *
> > +inflight_mem_alloc(const char *name, size_t size, int *fd) {
> > +	void *ptr;
> > +	int mfd = -1;
> > +	char fname[20] = "/tmp/memfd-XXXXXX";
> > +
> > +	*fd = -1;
> > +	mfd = mem_create(name, CLOEXEC);
> > +	if (mfd != -1) {
> > +		if (ftruncate(mfd, size) == -1) {
> > +			RTE_LOG(ERR, VHOST_CONFIG,
> > +				"ftruncate fail for alloc inflight buffer\n");
> > +			close(mfd);
> > +			return NULL;
> > +		}
> > +	} else {
> > +		mfd = mkstemp(fname);
> > +		unlink(fname);
> > +
> > +		if (mfd == -1) {
> > +			RTE_LOG(ERR, VHOST_CONFIG,
> > +				"mkstemp fail for alloc inflight buffer\n");
> > +			return NULL;
> > +		}
> > +
> > +		if (ftruncate(mfd, size) == -1) {
> > +			RTE_LOG(ERR, VHOST_CONFIG,
> > +				"ftruncate fail for alloc inflight buffer\n");
> > +			close(mfd);
> > +			return NULL;
> > +		}
> > +	}
> > +
> > +	ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, mfd, 0);
> > +	if (ptr == MAP_FAILED) {
> > +		RTE_LOG(ERR, VHOST_CONFIG,
> > +			"mmap fail for alloc inflight buffer\n");
> > +		close(mfd);
> > +		return NULL;
> > +	}
> > +
> > +	*fd = mfd;
> > +	return ptr;
> > +}
> > +
> > +static uint32_t
> > +get_pervq_shm_size_split(uint16_t queue_size) {
> > +	return ALIGN_UP(sizeof(struct rte_vhost_inflight_desc_split) *
> > +			queue_size + sizeof(uint64_t) + sizeof(uint16_t) * 4,
> > +			INFLIGHT_ALIGNMENT);
> > +}
> > +
> > +static uint32_t
> > +get_pervq_shm_size_packed(uint16_t queue_size) {
> > +	return ALIGN_UP(sizeof(struct rte_vhost_inflight_desc_packed) *
> > +			queue_size + sizeof(uint64_t) + sizeof(uint16_t) * 6 +
> > +			sizeof(uint8_t) * 9, INFLIGHT_ALIGNMENT); }
> > +
> > +static int
> > +vhost_user_get_inflight_fd(struct virtio_net **pdev,
> > +				     VhostUserMsg *msg,
> > +				     int main_fd __rte_unused)
> > +{
> > +	int fd, i, j;
> > +	uint64_t pervq_inflight_size, mmap_size;
> > +	void *addr;
> > +	uint16_t num_queues, queue_size;
> > +	struct virtio_net *dev = *pdev;
> > +	struct rte_vhost_inflight_info_packed *inflight_packed = NULL;
> > +
> > +	if (msg->size != sizeof(msg->payload.inflight)) {
> > +		RTE_LOG(ERR, VHOST_CONFIG,
> > +			"Invalid get_inflight_fd message size is %d",
> > +			msg->size);
> > +		return RTE_VHOST_MSG_RESULT_ERR;
> > +	}
> > +
> > +	dev->inflight_info = calloc(1, sizeof(struct inflight_mem_info));
> 
> You need to check whether dev->inflight_info has been allocated, otherwise
> memory may leak.
Yeah, Thanks. Will fix it.
> 
> > +	if (!dev->inflight_info) {
> > +		RTE_LOG(ERR, VHOST_CONFIG,
> > +			"Failed to alloc dev inflight area");
> > +		return RTE_VHOST_MSG_RESULT_ERR;
> > +	}
> > +
> > +	num_queues = msg->payload.inflight.num_queues;
> > +	queue_size = msg->payload.inflight.queue_size;
> > +
> > +	RTE_LOG(INFO, VHOST_CONFIG, "get_inflight_fd num_queues: %u\n",
> > +		msg->payload.inflight.num_queues);
> > +	RTE_LOG(INFO, VHOST_CONFIG, "get_inflight_fd queue_size: %u\n",
> > +		msg->payload.inflight.queue_size);
> > +
> > +	if (vq_is_packed(dev))
> > +		pervq_inflight_size = get_pervq_shm_size_packed(queue_size);
> > +	else
> > +		pervq_inflight_size = get_pervq_shm_size_split(queue_size);
> > +
> > +	mmap_size = num_queues * pervq_inflight_size;
> > +	addr = inflight_mem_alloc("vhost-inflight", mmap_size, &fd);
> > +	if (!addr) {
> > +		RTE_LOG(ERR, VHOST_CONFIG,
> > +			"Failed to alloc vhost inflight area");
> > +			msg->payload.inflight.mmap_size = 0;
> > +		return RTE_VHOST_MSG_RESULT_ERR;
> > +	}
> > +	memset(addr, 0, mmap_size);
> > +
> > +	dev->inflight_info->addr = addr;
> > +	dev->inflight_info->size = msg->payload.inflight.mmap_size =
> mmap_size;
> > +	dev->inflight_info->fd = msg->fds[0] = fd;
> > +	msg->payload.inflight.mmap_offset = 0;
> > +	msg->fd_num = 1;
> > +
> > +	if (vq_is_packed(dev)) {
> > +		for (i = 0; i < num_queues; i++) {
> > +			inflight_packed =
> > +				(struct rte_vhost_inflight_info_packed *)addr;
> > +			inflight_packed->used_wrap_counter = 1;
> > +			inflight_packed->old_used_wrap_counter = 1;
> > +			for (j = 0; j < queue_size; j++)
> > +				inflight_packed->desc[j].next = j + 1;
> > +			addr = (void *)((char *)addr + pervq_inflight_size);
> > +		}
> > +	}
> > +
> > +	RTE_LOG(INFO, VHOST_CONFIG,
> > +		"send inflight mmap_size: %"PRIu64"\n",
> > +		msg->payload.inflight.mmap_size);
> > +	RTE_LOG(INFO, VHOST_CONFIG,
> > +		"send inflight mmap_offset: %"PRIu64"\n",
> > +		msg->payload.inflight.mmap_offset);
> > +	RTE_LOG(INFO, VHOST_CONFIG,
> > +		"send inflight fd: %d\n", msg->fds[0]);
> > +
> > +	return RTE_VHOST_MSG_RESULT_REPLY;
> > +}
> > +
> > +static int
> > +vhost_user_set_inflight_fd(struct virtio_net **pdev, VhostUserMsg *msg,
> > +		int main_fd __rte_unused)
> > +{
> > +	int fd;
> > +	uint64_t mmap_size, mmap_offset;
> > +	uint16_t num_queues, queue_size;
> > +	uint32_t pervq_inflight_size;
> > +	void *addr;
> > +	struct virtio_net *dev = *pdev;
> > +
> > +	fd = msg->fds[0];
> > +	if (msg->size != sizeof(msg->payload.inflight) || fd < 0) {
> > +		RTE_LOG(ERR, VHOST_CONFIG,
> > +			"Invalid set_inflight_fd message size is %d,fd is %d\n",
> > +			msg->size, fd);
> > +		return RTE_VHOST_MSG_RESULT_ERR;
> > +	}
> > +
> > +	mmap_size = msg->payload.inflight.mmap_size;
> > +	mmap_offset = msg->payload.inflight.mmap_offset;
> > +	num_queues = msg->payload.inflight.num_queues;
> > +	queue_size = msg->payload.inflight.queue_size;
> > +
> > +	if (vq_is_packed(dev))
> > +		pervq_inflight_size = get_pervq_shm_size_packed(queue_size);
> > +	else
> > +		pervq_inflight_size = get_pervq_shm_size_split(queue_size);
> > +
> > +	RTE_LOG(INFO, VHOST_CONFIG,
> > +		"set_inflight_fd mmap_size: %"PRIu64"\n", mmap_size);
> > +	RTE_LOG(INFO, VHOST_CONFIG,
> > +		"set_inflight_fd mmap_offset: %"PRIu64"\n", mmap_offset);
> > +	RTE_LOG(INFO, VHOST_CONFIG,
> > +		"set_inflight_fd num_queues: %u\n", num_queues);
> > +	RTE_LOG(INFO, VHOST_CONFIG,
> > +		"set_inflight_fd queue_size: %u\n", queue_size);
> > +	RTE_LOG(INFO, VHOST_CONFIG,
> > +		"set_inflight_fd fd: %d\n", fd);
> > +	RTE_LOG(INFO, VHOST_CONFIG,
> > +		"set_inflight_fd pervq_inflight_size: %d\n",
> > +		pervq_inflight_size);
> > +
> > +	if (!dev->inflight_info) {
> > +		dev->inflight_info = calloc(1,
> > +					    sizeof(struct inflight_mem_info));
> > +		if (dev->inflight_info == NULL) {
> > +			RTE_LOG(ERR, VHOST_CONFIG,
> > +				"Failed to alloc dev inflight area");
> > +			return RTE_VHOST_MSG_RESULT_ERR;
> > +		}
> > +	}
> > +
> > +	if (dev->inflight_info->addr)
> > +		munmap(dev->inflight_info->addr, dev->inflight_info->size);
> 
> dev->inflight_info->addr won't be zeroed when below mmap() fails.
I think it should be zero when below mmap() fails as this function would return directly, so
The dev->inflight_info->addr would not been set.
> 
> > +
> > +	addr = mmap(0, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED,
> > +			fd, mmap_offset);
> > +	if (addr == MAP_FAILED) {
> > +		RTE_LOG(ERR, VHOST_CONFIG, "failed to mmap share
> memory.\n");
> > +		return RTE_VHOST_MSG_RESULT_ERR;
> > +	}
> > +
> > +	if (dev->inflight_info->fd)
> > +		close(dev->inflight_info->fd);
> > +
> > +	dev->inflight_info->fd = fd;
> > +	dev->inflight_info->addr = addr;
> > +	dev->inflight_info->size = mmap_size;
> > +
> > +	return RTE_VHOST_MSG_RESULT_OK;
> > +}
> > +
> >  static int
> >  vhost_user_set_vring_call(struct virtio_net **pdev, struct VhostUserMsg
> *msg,
> >  			int main_fd __rte_unused)
> > @@ -1762,9 +2019,10 @@ static vhost_message_handler_t
> vhost_message_handlers[VHOST_USER_MAX] = {
> >  	[VHOST_USER_POSTCOPY_ADVISE] = vhost_user_set_postcopy_advise,
> >  	[VHOST_USER_POSTCOPY_LISTEN] = vhost_user_set_postcopy_listen,
> >  	[VHOST_USER_POSTCOPY_END] = vhost_user_postcopy_end,
> > +	[VHOST_USER_GET_INFLIGHT_FD] = vhost_user_get_inflight_fd,
> > +	[VHOST_USER_SET_INFLIGHT_FD] = vhost_user_set_inflight_fd,
> >  };
> >
> > -
> >  /* return bytes# of read on success or negative val on failure. */
> > static int  read_vhost_message(int sockfd, struct VhostUserMsg *msg)
> > diff --git a/lib/librte_vhost/vhost_user.h
> > b/lib/librte_vhost/vhost_user.h index 17a1d7bca..6563f7315 100644
> > --- a/lib/librte_vhost/vhost_user.h
> > +++ b/lib/librte_vhost/vhost_user.h
> > @@ -54,7 +54,9 @@ typedef enum VhostUserRequest {
> >  	VHOST_USER_POSTCOPY_ADVISE = 28,
> >  	VHOST_USER_POSTCOPY_LISTEN = 29,
> >  	VHOST_USER_POSTCOPY_END = 30,
> > -	VHOST_USER_MAX = 31
> > +	VHOST_USER_GET_INFLIGHT_FD = 31,
> > +	VHOST_USER_SET_INFLIGHT_FD = 32,
> > +	VHOST_USER_MAX = 33
> >  } VhostUserRequest;
> >
> >  typedef enum VhostUserSlaveRequest {
> > --
> > 2.17.2
> >


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