[dpdk-dev] [PATCH RFC v2 06/12] lib/librte_vhost: cuse_set_memory_table

[Tetsuya Mukawa]

(2014/12/11 6:37), Huawei Xie wrote:
> cuse_set_memory_table
>
> Signed-off-by: Huawei Xie <huawei.xie at intel.com>
> ---
>  lib/librte_vhost/Makefile                     |   2 +-
>  lib/librte_vhost/vhost-net.h                  |   4 +-
>  lib/librte_vhost/vhost_cuse/vhost-net-cdev.c  |   7 +-
>  lib/librte_vhost/vhost_cuse/virtio-net-cdev.c |  85 +++++++
>  lib/librte_vhost/vhost_cuse/virtio-net-cdev.h |  45 ++++
>  lib/librte_vhost/virtio-net.c                 | 306 +-------------------------
>  6 files changed, 144 insertions(+), 305 deletions(-)
>  create mode 100644 lib/librte_vhost/vhost_cuse/virtio-net-cdev.h
>
> diff --git a/lib/librte_vhost/Makefile b/lib/librte_vhost/Makefile
> index 0b2f08f..e0d0ef6 100644
> --- a/lib/librte_vhost/Makefile
> +++ b/lib/librte_vhost/Makefile
> @@ -37,7 +37,7 @@ LIB = librte_vhost.a
>  CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -I vhost_cuse -O3 -D_FILE_OFFSET_BITS=64 -lfuse
>  LDFLAGS += -lfuse
>  # all source are stored in SRCS-y
> -SRCS-$(CONFIG_RTE_LIBRTE_VHOST) := vhost_cuse/vhost-net-cdev.c virtio-net.c vhost_rxtx.c
> +SRCS-$(CONFIG_RTE_LIBRTE_VHOST) := vhost_cuse/vhost-net-cdev.c vhost_cuse/virtio-net-cdev.c virtio-net.c vhost_rxtx.c
>  
>  # install includes
>  SYMLINK-$(CONFIG_RTE_LIBRTE_VHOST)-include += rte_virtio_net.h
> diff --git a/lib/librte_vhost/vhost-net.h b/lib/librte_vhost/vhost-net.h
> index 03a5c57..f7e96fd 100644
> --- a/lib/librte_vhost/vhost-net.h
> +++ b/lib/librte_vhost/vhost-net.h
> @@ -41,6 +41,8 @@
>  
>  #include <rte_log.h>
>  
> +#define VHOST_MEMORY_MAX_NREGIONS 8
> +
>  /* Macros for printing using RTE_LOG */
>  #define RTE_LOGTYPE_VHOST_CONFIG RTE_LOGTYPE_USER1
>  #define RTE_LOGTYPE_VHOST_DATA   RTE_LOGTYPE_USER1
> @@ -92,7 +94,7 @@ struct vhost_net_device_ops {
>  	int (*get_features)(struct vhost_device_ctx, uint64_t *);
>  	int (*set_features)(struct vhost_device_ctx, uint64_t *);
>  
> -	int (*set_mem_table)(struct vhost_device_ctx, const void *, uint32_t);
> +	int (*set_mem_table)(struct vhost_device_ctx, const struct virtio_memory_regions *, uint32_t nregions);
>  
>  	int (*set_vring_num)(struct vhost_device_ctx, struct vhost_vring_state *);
>  	int (*set_vring_addr)(struct vhost_device_ctx, struct vhost_vring_addr *);
> diff --git a/lib/librte_vhost/vhost_cuse/vhost-net-cdev.c b/lib/librte_vhost/vhost_cuse/vhost-net-cdev.c
> index 9424452..3422795 100644
> --- a/lib/librte_vhost/vhost_cuse/vhost-net-cdev.c
> +++ b/lib/librte_vhost/vhost_cuse/vhost-net-cdev.c
> @@ -46,6 +46,7 @@
>  #include <rte_string_fns.h>
>  #include <rte_virtio_net.h>
>  
> +#include "virtio-net-cdev.h"
>  #include "vhost-net.h"
>  #include "eventfd_link/eventfd_link.h"
>  
> @@ -60,7 +61,7 @@ static const char default_cdev[] = "vhost-net";
>  static const char eventfd_cdev[] = "/dev/eventfd-link";
>  
>  static struct fuse_session *session;
> -static struct vhost_net_device_ops const *ops;
> +struct vhost_net_device_ops const *ops;
>  
>  /*
>   * Returns vhost_device_ctx from given fuse_req_t. The index is populated later
> @@ -291,8 +292,8 @@ vhost_net_ioctl(fuse_req_t req, int cmd, void *arg,
>  			break;
>  
>  		default:
> -			result = ops->set_mem_table(ctx,
> -					in_buf, mem_temp.nregions);
> +			result = cuse_set_mem_table(ctx, in_buf,
> +				mem_temp.nregions);
>  			if (result)
>  				fuse_reply_err(req, EINVAL);
>  			else
> diff --git a/lib/librte_vhost/vhost_cuse/virtio-net-cdev.c b/lib/librte_vhost/vhost_cuse/virtio-net-cdev.c
> index 58ac3dd..edcbc10 100644
> --- a/lib/librte_vhost/vhost_cuse/virtio-net-cdev.c
> +++ b/lib/librte_vhost/vhost_cuse/virtio-net-cdev.c
> @@ -47,7 +47,11 @@
>  
>  #include <rte_log.h>
>  
> +#include "rte_virtio_net.h"
>  #include "vhost-net.h"
> +#include "virtio-net-cdev.h"
> +
> +extern struct vhost_net_device_ops const *ops;

I got warning from checkpatch.pl like 'WARNING: externs should be
avoided in .c files'.
It might be good to move it to the header file.

>  
>  /* Line size for reading maps file. */
>  static const uint32_t BUFSIZE = PATH_MAX;
> @@ -253,3 +257,84 @@ host_memory_map(pid_t pid, uint64_t addr,
>  
>  	return 0;
>  }
> +
> +int
> +cuse_set_mem_table(struct vhost_device_ctx ctx,
> +	const struct vhost_memory *mem_regions_addr, uint32_t nregions)
> +{
> +	uint64_t size = offsetof(struct vhost_memory, regions);
> +	uint32_t idx, valid_regions;
> +	struct virtio_memory_regions regions[VHOST_MEMORY_MAX_NREGIONS];
> +	struct vhost_memory_region *mem_regions = (void *)(uintptr_t)
> +		((uint64_t)(uintptr_t)mem_regions_addr + size);
> +	uint64_t base_address = 0, mapped_address, mapped_size;
> +
> +	for (idx = 0; idx < nregions; idx++) {
> +		regions[idx].guest_phys_address =
> +			mem_regions[idx].guest_phys_addr;
> +		regions[idx].guest_phys_address_end =
> +			regions[idx].guest_phys_address +
> +			mem_regions[idx].memory_size;
> +		regions[idx].memory_size =
> +			mem_regions[idx].memory_size;
> +		regions[idx].userspace_address =
> +			mem_regions[idx].userspace_addr;
> +
> +		LOG_DEBUG(VHOST_CONFIG,
> +			"REGION: %u - GPA: %p - QVA: %p - SIZE (%"PRIu64")\n",
> +			idx,
> +			(void *)(uintptr_t)regions[idx].guest_phys_address,
> +			(void *)(uintptr_t)regions[idx].userspace_address,
> +			regions[idx].memory_size);
> +
> +		/*set the base address mapping*/
> +		if (regions[idx].guest_phys_address == 0x0) {
> +			base_address =
> +				regions[idx].userspace_address;
> +			/* Map VM memory file */
> +			if (host_memory_map(ctx.pid, base_address,
> +				&mapped_address, &mapped_size) != 0) {
> +				return -1;
> +			}
> +		}
> +	}
> +
> +	/* Check that we have a valid base address. */
> +	if (base_address == 0) {
> +		RTE_LOG(ERR, VHOST_CONFIG,
> +			"Failed to find base address of qemu memory file.\n");
> +		return -1;
> +	}
> +
> +	valid_regions = nregions;
> +	for (idx = 0; idx < nregions; idx++) {
> +		if ((regions[idx].userspace_address < base_address) ||
> +			(regions[idx].userspace_address >
> +			(base_address + mapped_size)))
> +			valid_regions--;
> +	}
> +
> +	if (valid_regions != nregions) {
> +		valid_regions = 0;
> +		for (idx = nregions; 0 != idx--; ) {
> +			if ((regions[idx].userspace_address < base_address) ||
> +			(regions[idx].userspace_address >
> +			(base_address + mapped_size))) {
> +				memmove(&regions[idx], &regions[idx + 1],
> +					sizeof(struct virtio_memory_regions) *
> +					valid_regions);
> +			} else
> +				valid_regions++;
> +		}
> +	}
> +
> +	for (idx = 0; idx < valid_regions; idx++) {
> +		regions[idx].address_offset =
> +			mapped_address - base_address +
> +			regions[idx].userspace_address -
> +			regions[idx].guest_phys_address;
> +	}
> +
> +	ops->set_mem_table(ctx, &regions[0], valid_regions);
> +	return 0;
> +}
> diff --git a/lib/librte_vhost/vhost_cuse/virtio-net-cdev.h b/lib/librte_vhost/vhost_cuse/virtio-net-cdev.h
> new file mode 100644
> index 0000000..5ee81b1
> --- /dev/null
> +++ b/lib/librte_vhost/vhost_cuse/virtio-net-cdev.h
> @@ -0,0 +1,45 @@
> +/*-
> + *   BSD LICENSE
> + *
> + *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
> + *   All rights reserved.
> + *
> + *   Redistribution and use in source and binary forms, with or without
> + *   modification, are permitted provided that the following conditions
> + *   are met:
> + *
> + *     * Redistributions of source code must retain the above copyright
> + *       notice, this list of conditions and the following disclaimer.
> + *     * Redistributions in binary form must reproduce the above copyright
> + *       notice, this list of conditions and the following disclaimer in
> + *       the documentation and/or other materials provided with the
> + *       distribution.
> + *     * Neither the name of Intel Corporation nor the names of its
> + *       contributors may be used to endorse or promote products derived
> + *       from this software without specific prior written permission.
> + *
> + *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
> + *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
> + *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
> + *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
> + *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> + *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
> + *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
> + *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
> + *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> + *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
> + *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> + */
> +#ifndef _VIRTIO_NET_CDEV_H
> +#define _VIRTIO_NET_CDEV_H
> +
> +#include <stdint.h>
> +#include <linux/vhost.h>
> +
> +#include "vhost-net.h"
> +
> +int
> +cuse_set_mem_table(struct vhost_device_ctx ctx,
> +	const struct vhost_memory *mem_regions_addr, uint32_t nregions);
> +
> +#endif
> diff --git a/lib/librte_vhost/virtio-net.c b/lib/librte_vhost/virtio-net.c
> index d1b1aaa..f81e459 100644
> --- a/lib/librte_vhost/virtio-net.c
> +++ b/lib/librte_vhost/virtio-net.c
> @@ -31,8 +31,6 @@
>   *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
>   */
>  
> -#include <dirent.h>
> -#include <fuse/cuse_lowlevel.h>
>  #include <linux/vhost.h>
>  #include <linux/virtio_net.h>
>  #include <stddef.h>
> @@ -67,26 +65,6 @@ static struct virtio_net_config_ll *ll_root;
>  				  (1ULL << VIRTIO_NET_F_CTRL_RX))
>  static uint64_t VHOST_FEATURES = VHOST_SUPPORTED_FEATURES;
>  
> -/* Line size for reading maps file. */
> -static const uint32_t BUFSIZE = PATH_MAX;
> -
> -/* Size of prot char array in procmap. */
> -#define PROT_SZ 5
> -
> -/* Number of elements in procmap struct. */
> -#define PROCMAP_SZ 8
> -
> -/* Structure containing information gathered from maps file. */
> -struct procmap {
> -	uint64_t va_start;	/* Start virtual address in file. */
> -	uint64_t len;		/* Size of file. */
> -	uint64_t pgoff;		/* Not used. */
> -	uint32_t maj;		/* Not used. */
> -	uint32_t min;		/* Not used. */
> -	uint32_t ino;		/* Not used. */
> -	char prot[PROT_SZ];	/* Not used. */
> -	char fname[PATH_MAX];	/* File name. */
> -};
>  
>  /*
>   * Converts QEMU virtual address to Vhost virtual address. This function is
> @@ -113,191 +91,6 @@ qva_to_vva(struct virtio_net *dev, uint64_t qemu_va)
>  	return vhost_va;
>  }
>  
> -/*
> - * Locate the file containing QEMU's memory space and
> - * map it to our address space.
> - */
> -static int
> -host_memory_map(struct virtio_net *dev, struct virtio_memory *mem,
> -	pid_t pid, uint64_t addr)
> -{
> -	struct dirent *dptr = NULL;
> -	struct procmap procmap;
> -	DIR *dp = NULL;
> -	int fd;
> -	int i;
> -	char memfile[PATH_MAX];
> -	char mapfile[PATH_MAX];
> -	char procdir[PATH_MAX];
> -	char resolved_path[PATH_MAX];
> -	char *path = NULL;
> -	FILE *fmap;
> -	void *map;
> -	uint8_t found = 0;
> -	char line[BUFSIZE];
> -	char dlm[] = "-   :   ";
> -	char *str, *sp, *in[PROCMAP_SZ];
> -	char *end = NULL;
> -
> -	/* Path where mem files are located. */
> -	snprintf(procdir, PATH_MAX, "/proc/%u/fd/", pid);
> -	/* Maps file used to locate mem file. */
> -	snprintf(mapfile, PATH_MAX, "/proc/%u/maps", pid);
> -
> -	fmap = fopen(mapfile, "r");
> -	if (fmap == NULL) {
> -		RTE_LOG(ERR, VHOST_CONFIG,
> -			"(%"PRIu64") Failed to open maps file for pid %d\n",
> -			dev->device_fh, pid);
> -		return -1;
> -	}
> -
> -	/* Read through maps file until we find out base_address. */
> -	while (fgets(line, BUFSIZE, fmap) != 0) {
> -		str = line;
> -		errno = 0;
> -		/* Split line into fields. */
> -		for (i = 0; i < PROCMAP_SZ; i++) {
> -			in[i] = strtok_r(str, &dlm[i], &sp);
> -			if ((in[i] == NULL) || (errno != 0)) {
> -				fclose(fmap);
> -				return -1;
> -			}
> -			str = NULL;
> -		}
> -
> -		/* Convert/Copy each field as needed. */
> -		procmap.va_start = strtoull(in[0], &end, 16);
> -		if ((in[0] == '\0') || (end == NULL) || (*end != '\0') ||
> -			(errno != 0)) {
> -			fclose(fmap);
> -			return -1;
> -		}
> -
> -		procmap.len = strtoull(in[1], &end, 16);
> -		if ((in[1] == '\0') || (end == NULL) || (*end != '\0') ||
> -			(errno != 0)) {
> -			fclose(fmap);
> -			return -1;
> -		}
> -
> -		procmap.pgoff = strtoull(in[3], &end, 16);
> -		if ((in[3] == '\0') || (end == NULL) || (*end != '\0') ||
> -			(errno != 0)) {
> -			fclose(fmap);
> -			return -1;
> -		}
> -
> -		procmap.maj = strtoul(in[4], &end, 16);
> -		if ((in[4] == '\0') || (end == NULL) || (*end != '\0') ||
> -			(errno != 0)) {
> -			fclose(fmap);
> -			return -1;
> -		}
> -
> -		procmap.min = strtoul(in[5], &end, 16);
> -		if ((in[5] == '\0') || (end == NULL) || (*end != '\0') ||
> -			(errno != 0)) {
> -			fclose(fmap);
> -			return -1;
> -		}
> -
> -		procmap.ino = strtoul(in[6], &end, 16);
> -		if ((in[6] == '\0') || (end == NULL) || (*end != '\0') ||
> -			(errno != 0)) {
> -			fclose(fmap);
> -			return -1;
> -		}
> -
> -		memcpy(&procmap.prot, in[2], PROT_SZ);
> -		memcpy(&procmap.fname, in[7], PATH_MAX);
> -
> -		if (procmap.va_start == addr) {
> -			procmap.len = procmap.len - procmap.va_start;
> -			found = 1;
> -			break;
> -		}
> -	}
> -	fclose(fmap);
> -
> -	if (!found) {
> -		RTE_LOG(ERR, VHOST_CONFIG,
> -			"(%"PRIu64") Failed to find memory file in pid %d maps file\n",
> -			dev->device_fh, pid);
> -		return -1;
> -	}
> -
> -	/* Find the guest memory file among the process fds. */
> -	dp = opendir(procdir);
> -	if (dp == NULL) {
> -		RTE_LOG(ERR, VHOST_CONFIG,
> -			"(%"PRIu64") Cannot open pid %d process directory\n",
> -			dev->device_fh, pid);
> -		return -1;
> -	}
> -
> -	found = 0;
> -
> -	/* Read the fd directory contents. */
> -	while (NULL != (dptr = readdir(dp))) {
> -		snprintf(memfile, PATH_MAX, "/proc/%u/fd/%s",
> -				pid, dptr->d_name);
> -		path = realpath(memfile, resolved_path);
> -		if ((path == NULL) && (strlen(resolved_path) == 0)) {
> -			RTE_LOG(ERR, VHOST_CONFIG,
> -				"(%"PRIu64") Failed to resolve fd directory\n",
> -				dev->device_fh);
> -			closedir(dp);
> -			return -1;
> -		}
> -		if (strncmp(resolved_path, procmap.fname,
> -			strnlen(procmap.fname, PATH_MAX)) == 0) {
> -			found = 1;
> -			break;
> -		}
> -	}
> -
> -	closedir(dp);
> -
> -	if (found == 0) {
> -		RTE_LOG(ERR, VHOST_CONFIG,
> -			"(%"PRIu64") Failed to find memory file for pid %d\n",
> -			dev->device_fh, pid);
> -		return -1;
> -	}
> -	/* Open the shared memory file and map the memory into this process. */
> -	fd = open(memfile, O_RDWR);
> -
> -	if (fd == -1) {
> -		RTE_LOG(ERR, VHOST_CONFIG,
> -			"(%"PRIu64") Failed to open %s for pid %d\n",
> -			dev->device_fh, memfile, pid);
> -		return -1;
> -	}
> -
> -	map = mmap(0, (size_t)procmap.len, PROT_READ|PROT_WRITE,
> -		MAP_POPULATE|MAP_SHARED, fd, 0);
> -	close(fd);
> -
> -	if (map == MAP_FAILED) {
> -		RTE_LOG(ERR, VHOST_CONFIG,
> -			"(%"PRIu64") Error mapping the file %s for pid %d\n",
> -			dev->device_fh, memfile, pid);
> -		return -1;
> -	}
> -
> -	/* Store the memory address and size in the device data structure */
> -	mem->mapped_address = (uint64_t)(uintptr_t)map;
> -	mem->mapped_size = procmap.len;
> -
> -	LOG_DEBUG(VHOST_CONFIG,
> -		"(%"PRIu64") Mem File: %s->%s - Size: %llu - VA: %p\n",
> -		dev->device_fh,
> -		memfile, resolved_path,
> -		(unsigned long long)mem->mapped_size, map);
> -
> -	return 0;
> -}

Need to move above code related with host_memory_map() to
"[PATCH RFC v2 04/12] lib/librte_vhost: copy of host_memory_map from
virtio-net.c to new file virtio-net-cdev.c "?

>  
>  /*
>   * Retrieves an entry from the devices configuration linked list.
> @@ -646,14 +439,12 @@ set_features(struct vhost_device_ctx ctx, uint64_t *pu)
>   * This includes storing offsets used to translate buffer addresses.
>   */
>  static int
> -set_mem_table(struct vhost_device_ctx ctx, const void *mem_regions_addr,
> -	uint32_t nregions)
> +set_mem_table(struct vhost_device_ctx ctx,
> +	const struct virtio_memory_regions *regions, uint32_t nregions)
>  {
>  	struct virtio_net *dev;
> -	struct vhost_memory_region *mem_regions;
>  	struct virtio_memory *mem;
> -	uint64_t size = offsetof(struct vhost_memory, regions);
> -	uint32_t regionidx, valid_regions;
> +	uint32_t regionidx;
>  
>  	dev = get_device(ctx);
>  	if (dev == NULL)
> @@ -677,104 +468,19 @@ set_mem_table(struct vhost_device_ctx ctx, const void *mem_regions_addr,
>  
>  	mem->nregions = nregions;
>  
> -	mem_regions = (void *)(uintptr_t)
> -			((uint64_t)(uintptr_t)mem_regions_addr + size);
> -
>  	for (regionidx = 0; regionidx < mem->nregions; regionidx++) {
>  		/* Populate the region structure for each region. */
> -		mem->regions[regionidx].guest_phys_address =
> -			mem_regions[regionidx].guest_phys_addr;
> -		mem->regions[regionidx].guest_phys_address_end =
> -			mem->regions[regionidx].guest_phys_address +
> -			mem_regions[regionidx].memory_size;
> -		mem->regions[regionidx].memory_size =
> -			mem_regions[regionidx].memory_size;
> -		mem->regions[regionidx].userspace_address =
> -			mem_regions[regionidx].userspace_addr;
> -
> -		LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") REGION: %u - GPA: %p - QEMU VA: %p - SIZE (%"PRIu64")\n", dev->device_fh,
> -			regionidx,
> -			(void *)(uintptr_t)mem->regions[regionidx].guest_phys_address,
> -			(void *)(uintptr_t)mem->regions[regionidx].userspace_address,
> -			mem->regions[regionidx].memory_size);
> -
> -		/*set the base address mapping*/
> +		mem->regions[regionidx] = regions[regionidx];
>  		if (mem->regions[regionidx].guest_phys_address == 0x0) {
>  			mem->base_address =
>  				mem->regions[regionidx].userspace_address;
> -			/* Map VM memory file */
> -			if (host_memory_map(dev, mem, ctx.pid,
> -				mem->base_address) != 0) {
> -				free(mem);
> -				return -1;
> -			}
> +			mem->mapped_address =
> +				mem->regions[regionidx].address_offset;
>  		}
>  	}
>  
> -	/* Check that we have a valid base address. */
> -	if (mem->base_address == 0) {
> -		RTE_LOG(ERR, VHOST_CONFIG, "(%"PRIu64") Failed to find base address of qemu memory file.\n", dev->device_fh);
> -		free(mem);
> -		return -1;
> -	}
> -
> -	/*
> -	 * Check if all of our regions have valid mappings.
> -	 * Usually one does not exist in the QEMU memory file.
> -	 */
> -	valid_regions = mem->nregions;
> -	for (regionidx = 0; regionidx < mem->nregions; regionidx++) {
> -		if ((mem->regions[regionidx].userspace_address <
> -			mem->base_address) ||
> -			(mem->regions[regionidx].userspace_address >
> -			(mem->base_address + mem->mapped_size)))
> -				valid_regions--;
> -	}
> -
> -	/*
> -	 * If a region does not have a valid mapping,
> -	 * we rebuild our memory struct to contain only valid entries.
> -	 */
> -	if (valid_regions != mem->nregions) {
> -		LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") Not all memory regions exist in the QEMU mem file. Re-populating mem structure\n",
> -			dev->device_fh);
> -
> -		/*
> -		 * Re-populate the memory structure with only valid regions.
> -		 * Invalid regions are over-written with memmove.
> -		 */
> -		valid_regions = 0;
> -
> -		for (regionidx = mem->nregions; 0 != regionidx--;) {
> -			if ((mem->regions[regionidx].userspace_address <
> -				mem->base_address) ||
> -				(mem->regions[regionidx].userspace_address >
> -				(mem->base_address + mem->mapped_size))) {
> -				memmove(&mem->regions[regionidx],
> -					&mem->regions[regionidx + 1],
> -					sizeof(struct virtio_memory_regions) *
> -						valid_regions);
> -			} else {
> -				valid_regions++;
> -			}
> -		}
> -	}
> -	mem->nregions = valid_regions;
>  	dev->mem = mem;
>  
> -	/*
> -	 * Calculate the address offset for each region.
> -	 * This offset is used to identify the vhost virtual address
> -	 * corresponding to a QEMU guest physical address.
> -	 */
> -	for (regionidx = 0; regionidx < dev->mem->nregions; regionidx++) {
> -		dev->mem->regions[regionidx].address_offset =
> -			dev->mem->regions[regionidx].userspace_address -
> -				dev->mem->base_address +
> -				dev->mem->mapped_address -
> -				dev->mem->regions[regionidx].guest_phys_address;
> -
> -	}
>  	return 0;
>  }
>