X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;ds=sidebyside;f=examples%2Fvhost_xen%2Fxenstore_parse.c;fp=examples%2Fvhost_xen%2Fxenstore_parse.c;h=26d2432084dac611562c446a7443e963bdb698ff;hb=97f17497d162afdb82c8704bf097f0fee3724b2e;hp=0000000000000000000000000000000000000000;hpb=e04be89c2409570e0055b2cda60bd11395bb93b0;p=deb_dpdk.git

diff --git a/examples/vhost_xen/xenstore_parse.c b/examples/vhost_xen/xenstore_parse.c
new file mode 100644
index 00000000..26d24320
--- /dev/null
+++ b/examples/vhost_xen/xenstore_parse.c
@@ -0,0 +1,775 @@
+/*-
+ *   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.
+ */
+
+#include <stdint.h>
+#include <unistd.h>
+#include <inttypes.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <xen/sys/gntalloc.h>
+#include <xen/sys/gntdev.h>
+#include <xen/xen-compat.h>
+#if __XEN_LATEST_INTERFACE_VERSION__ < 0x00040200
+#include <xs.h>
+#else
+#include <xenstore.h>
+#endif
+
+#include <rte_common.h>
+#include <rte_memory.h>
+#include <rte_eal.h>
+#include <rte_malloc.h>
+#include <rte_string_fns.h>
+#include <rte_log.h>
+#include <rte_debug.h>
+
+#include "xen_vhost.h"
+
+/* xenstore handle */
+static struct xs_handle *xs = NULL;
+
+/* gntdev file descriptor to map grant pages */
+static int d_fd = -1;
+
+/*
+ *  The grant node format in xenstore for vring/mpool is like:
+ *  idx#_rx_vring_gref = "gref1#, gref2#, gref3#"
+ *  idx#_mempool_gref  = "gref1#, gref2#, gref3#"
+ *  each gref# is the grant reference for a shared page.
+ *  In each shared page, we store the grant_node_item items.
+ */
+struct grant_node_item {
+	uint32_t gref;
+	uint32_t pfn;
+} __attribute__((packed));
+
+int cmdline_parse_etheraddr(void *tk, const char *srcbuf,
+	void *res, unsigned ressize);
+
+/* Map grant ref refid at addr_ori*/
+static void *
+xen_grant_mmap(void *addr_ori, int domid, int refid, uint64_t *pindex)
+{
+	struct ioctl_gntdev_map_grant_ref arg;
+	void *addr = NULL;
+	int pg_sz = getpagesize();
+
+	arg.count = 1;
+	arg.refs[0].domid = domid;
+	arg.refs[0].ref = refid;
+
+	int rv = ioctl(d_fd, IOCTL_GNTDEV_MAP_GRANT_REF, &arg);
+	if (rv) {
+		RTE_LOG(ERR, XENHOST, "  %s: (%d,%d) %s (ioctl failed)\n", __func__,
+				domid, refid, strerror(errno));
+		return NULL;
+	}
+
+	if (addr_ori == NULL)
+		addr = mmap(addr_ori, pg_sz, PROT_READ|PROT_WRITE, MAP_SHARED,
+				d_fd, arg.index);
+	else
+		addr = mmap(addr_ori, pg_sz, PROT_READ|PROT_WRITE, MAP_SHARED | MAP_FIXED,
+				d_fd, arg.index);
+
+	if (addr == MAP_FAILED) {
+		RTE_LOG(ERR, XENHOST, "  %s: (%d, %d) %s (map failed)\n", __func__,
+				domid, refid, strerror(errno));
+		return NULL;
+	}
+
+	if (pindex)
+		*pindex = arg.index;
+
+	return addr;
+}
+
+/* Unmap one grant ref, and munmap must be called before this */
+static int
+xen_unmap_grant_ref(uint64_t index)
+{
+	struct ioctl_gntdev_unmap_grant_ref arg;
+	int rv;
+
+	arg.count = 1;
+	arg.index = index;
+	rv = ioctl(d_fd, IOCTL_GNTDEV_UNMAP_GRANT_REF, &arg);
+	if (rv) {
+		RTE_LOG(ERR, XENHOST, "  %s: index 0x%" PRIx64 "unmap failed\n", __func__, index);
+		return -1;
+	}
+	return 0;
+}
+
+/*
+ * Reserve a virtual address space.
+ * On success, returns the pointer. On failure, returns NULL.
+ */
+static void *
+get_xen_virtual(size_t size, size_t page_sz)
+{
+	void *addr;
+	uintptr_t aligned_addr;
+
+	addr = mmap(NULL, size + page_sz, PROT_READ, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+	if (addr == MAP_FAILED) {
+		RTE_LOG(ERR, XENHOST, "failed get a virtual area\n");
+		return NULL;
+	}
+
+	aligned_addr = RTE_ALIGN_CEIL((uintptr_t)addr, page_sz);
+	munmap(addr, aligned_addr - (uintptr_t)addr);
+	munmap((void *)(aligned_addr + size), page_sz + (uintptr_t)addr - aligned_addr);
+	addr = (void *)(aligned_addr);
+
+	return addr;
+}
+
+static void
+free_xen_virtual(void *addr, size_t size, size_t page_sz __rte_unused)
+{
+	if (addr)
+		munmap(addr, size);
+}
+
+/*
+ * Returns val str in xenstore.
+ * @param path
+ *  Full path string for key
+ * @return
+ *  Pointer to Val str, NULL on failure
+ */
+static char *
+xen_read_node(char *path, uint32_t *len)
+{
+	char *buf;
+
+	buf = xs_read(xs, XBT_NULL, path, len);
+	return buf;
+}
+
+static int
+cal_pagenum(struct xen_gnt *gnt)
+{
+	unsigned int i;
+	/*
+	 * the items in the page are in the format of
+	 * gref#,pfn#,...,gref#,pfn#
+	 * FIXME, 0 is reserved by system, use it as terminator.
+	 */
+	for (i = 0; i < (PAGE_PFNNUM) / 2; i++) {
+		if (gnt->gref_pfn[i * 2].gref <= 0)
+			break;
+	}
+
+	return i;
+}
+
+/* Frees memory allocated to a grant node */
+static void
+xen_free_gntnode(struct xen_gntnode *gntnode)
+{
+	if (gntnode == NULL)
+		return;
+	free(gntnode->gnt_info);
+	free(gntnode);
+}
+
+/*
+ * Parse a grant node.
+ * @param domid
+ *  Guest domain id.
+ * @param path
+ *  Full path string for a grant node, like for the following (key, val) pair
+ *  idx#_mempool_gref = "gref#, gref#, gref#"
+ *  path = 'local/domain/domid/control/dpdk/idx#_mempool_gref'
+ *  gref# is a shared page contain packed (gref,pfn) entries
+ * @return
+ *  Returns the pointer to xen_gntnode
+ */
+static struct xen_gntnode *
+parse_gntnode(int dom_id, char *path)
+{
+	char **gref_list = NULL;
+	uint32_t i, len, gref_num;
+	void *addr = NULL;
+	char *buf = NULL;
+	struct xen_gntnode *gntnode = NULL;
+	struct xen_gnt *gnt = NULL;
+	int pg_sz = getpagesize();
+	char *end;
+	uint64_t index;
+
+	if ((buf = xen_read_node(path, &len)) == NULL)
+		goto err;
+
+	gref_list = malloc(MAX_GREF_PER_NODE * sizeof(char *));
+	if (gref_list == NULL)
+		goto err;
+
+	gref_num = rte_strsplit(buf, len, gref_list, MAX_GREF_PER_NODE,
+			XEN_GREF_SPLITTOKEN);
+	if (gref_num == 0) {
+		RTE_LOG(ERR, XENHOST, "  %s: invalid grant node format\n", __func__);
+		goto err;
+	}
+
+	gntnode = calloc(1, sizeof(struct xen_gntnode));
+	gnt = calloc(gref_num, sizeof(struct xen_gnt));
+	if (gnt == NULL || gntnode == NULL)
+		goto err;
+
+	for (i = 0; i < gref_num; i++) {
+		errno = 0;
+		gnt[i].gref = strtol(gref_list[i], &end, 0);
+		if (errno != 0 || end == NULL || end == gref_list[i] ||
+			(*end != '\0' &&  *end != XEN_GREF_SPLITTOKEN)) {
+			RTE_LOG(ERR, XENHOST, "  %s: parse grant node item failed\n", __func__);
+			goto err;
+		}
+		addr = xen_grant_mmap(NULL, dom_id, gnt[i].gref, &index);
+		if (addr == NULL) {
+			RTE_LOG(ERR, XENHOST, "  %s: map gref %u failed\n", __func__, gnt[i].gref);
+			goto err;
+		}
+		RTE_LOG(INFO, XENHOST, "      %s: map gref %u to %p\n", __func__, gnt[i].gref, addr);
+		memcpy(gnt[i].gref_pfn, addr, pg_sz);
+		if (munmap(addr, pg_sz)) {
+			RTE_LOG(INFO, XENHOST, "  %s: unmap gref %u failed\n", __func__, gnt[i].gref);
+			goto err;
+		}
+		if (xen_unmap_grant_ref(index)) {
+			RTE_LOG(INFO, XENHOST, "  %s: release gref %u failed\n", __func__, gnt[i].gref);
+			goto err;
+		}
+
+	}
+
+	gntnode->gnt_num  = gref_num;
+	gntnode->gnt_info = gnt;
+
+	free(buf);
+	free(gref_list);
+	return gntnode;
+
+err:
+	free(gnt);
+	free(gntnode);
+	free(gref_list);
+	free(buf);
+	return NULL;
+}
+
+/*
+ * This function maps grant node of vring or mbuf pool to a continous virtual address space,
+ * and returns mapped address, pfn array, index array
+ * @param gntnode
+ *  Pointer to grant node
+ * @param domid
+ *  Guest domain id
+ * @param ppfn
+ *  Pointer to pfn array, caller should free this array
+ * @param pgs
+ *  Pointer to number of pages
+ * @param ppindex
+ *  Pointer to index array, used to release grefs when to free this node
+ * @return
+ *  Pointer to mapped virtual address, NULL on failure
+ */
+static void *
+map_gntnode(struct xen_gntnode *gntnode, int domid, uint32_t **ppfn, uint32_t *pgs, uint64_t **ppindex)
+{
+	struct xen_gnt *gnt;
+	uint32_t i, j;
+	size_t total_pages = 0;
+	void *addr;
+	uint32_t *pfn;
+	uint64_t *pindex;
+	uint32_t pfn_num = 0;
+	int pg_sz;
+
+	if (gntnode == NULL)
+		return NULL;
+
+	pg_sz = getpagesize();
+	for (i = 0; i < gntnode->gnt_num; i++) {
+		gnt = gntnode->gnt_info + i;
+		total_pages += cal_pagenum(gnt);
+	}
+	if ((addr = get_xen_virtual(total_pages * pg_sz, pg_sz)) == NULL) {
+		RTE_LOG(ERR, XENHOST, "  %s: failed get_xen_virtual\n", __func__);
+		return NULL;
+	}
+	pfn = calloc(total_pages, (size_t)sizeof(uint32_t));
+	pindex = calloc(total_pages, (size_t)sizeof(uint64_t));
+	if (pfn == NULL || pindex == NULL) {
+		free_xen_virtual(addr, total_pages * pg_sz, pg_sz);
+		free(pfn);
+		free(pindex);
+		return NULL;
+	}
+
+	RTE_LOG(INFO, XENHOST, "    %s: total pages:%zu, map to [%p, %p]\n", __func__, total_pages, addr, RTE_PTR_ADD(addr, total_pages * pg_sz - 1));
+	for (i = 0; i < gntnode->gnt_num; i++) {
+		gnt = gntnode->gnt_info + i;
+		for (j = 0; j < (PAGE_PFNNUM) / 2; j++) {
+			if ((gnt->gref_pfn[j * 2].gref) <= 0)
+				goto _end;
+			/*alternative: batch map, or through libxc*/
+			if (xen_grant_mmap(RTE_PTR_ADD(addr, pfn_num * pg_sz),
+					domid,
+					gnt->gref_pfn[j * 2].gref,
+					&pindex[pfn_num]) == NULL) {
+				goto mmap_failed;
+			}
+			pfn[pfn_num] = gnt->gref_pfn[j * 2 + 1].pfn_num;
+			pfn_num++;
+		}
+	}
+
+mmap_failed:
+	if (pfn_num)
+		munmap(addr, pfn_num * pg_sz);
+	for (i = 0; i < pfn_num; i++) {
+		xen_unmap_grant_ref(pindex[i]);
+	}
+	free(pindex);
+	free(pfn);
+	return NULL;
+
+_end:
+	if (ppindex)
+		*ppindex = pindex;
+	else
+		free(pindex);
+	if (ppfn)
+		*ppfn = pfn;
+	else
+		free(pfn);
+	if (pgs)
+		*pgs = total_pages;
+
+	return addr;
+}
+
+static int
+parse_mpool_va(struct xen_mempool *mempool)
+{
+	char path[PATH_MAX] = {0};
+	char *buf;
+	uint32_t len;
+	char *end;
+	int ret = -1;
+
+	errno = 0;
+	snprintf(path, sizeof(path),
+		XEN_VM_ROOTNODE_FMT"/%d_"XEN_GVA_SUFFIX,
+		mempool->dom_id, mempool->pool_idx);
+
+	if((buf = xen_read_node(path, &len)) == NULL)
+		goto out;
+	mempool->gva = (void *)strtoul(buf, &end, 16);
+	if (errno != 0 || end == NULL || end == buf || *end != '\0') {
+		mempool->gva = NULL;
+		goto out;
+	}
+	ret = 0;
+out:
+	free(buf);
+	return ret;
+}
+
+/*
+ * map mbuf pool
+ */
+static int
+map_mempoolnode(struct xen_gntnode *gntnode,
+			struct xen_mempool *mempool)
+{
+	if (gntnode == NULL || mempool == NULL)
+		return -1;
+
+	mempool->hva =
+		map_gntnode(gntnode, mempool->dom_id, &mempool->mempfn_tbl, &mempool->mempfn_num, &mempool->pindex);
+
+	RTE_LOG(INFO, XENHOST, "  %s: map mempool at %p\n", __func__, (void *)mempool->hva);
+	if (mempool->hva)
+		return 0;
+	else {
+		return -1;
+	}
+}
+
+void
+cleanup_mempool(struct xen_mempool *mempool)
+{
+	int pg_sz = getpagesize();
+	uint32_t i;
+
+	if (mempool->hva)
+		munmap(mempool->hva, mempool->mempfn_num * pg_sz);
+	mempool->hva = NULL;
+
+	if (mempool->pindex) {
+		RTE_LOG(INFO, XENHOST, "  %s: unmap dom %02u mempool%02u %u grefs\n",
+			__func__,
+			mempool->dom_id,
+			mempool->pool_idx,
+			mempool->mempfn_num);
+		for (i = 0; i < mempool->mempfn_num; i ++) {
+			xen_unmap_grant_ref(mempool->pindex[i]);
+		}
+	}
+	mempool->pindex = NULL;
+
+	free(mempool->mempfn_tbl);
+	mempool->mempfn_tbl = NULL;
+}
+
+/*
+ * process mempool node idx#_mempool_gref, idx = 0, 1, 2...
+ * untill we encounter a node that doesn't exist.
+ */
+int
+parse_mempoolnode(struct xen_guest *guest)
+{
+	uint32_t i, len;
+	char path[PATH_MAX] = {0};
+	struct xen_gntnode *gntnode = NULL;
+	struct xen_mempool *mempool = NULL;
+	char *buf;
+
+	bzero(&guest->mempool, MAX_XENVIRT_MEMPOOL * sizeof(guest->mempool[0]));
+	guest->pool_num = 0;
+
+	while (1) {
+		/* check if null terminated */
+		snprintf(path, sizeof(path),
+			XEN_VM_ROOTNODE_FMT"/%d_"XEN_MEMPOOL_SUFFIX,
+			guest->dom_id,
+			guest->pool_num);
+
+		if ((buf = xen_read_node(path, &len)) != NULL) {
+			/* this node exists */
+			free(buf);
+		} else {
+			if (guest->pool_num == 0) {
+				RTE_LOG(ERR, PMD, "no mempool found\n");
+				return -1;
+			}
+			break;
+		}
+
+		mempool = &guest->mempool[guest->pool_num];
+		mempool->dom_id = guest->dom_id;
+		mempool->pool_idx = guest->pool_num;
+
+		RTE_LOG(INFO, XENHOST, "  %s: mempool %u parse gntnode %s\n", __func__, guest->pool_num, path);
+		gntnode = parse_gntnode(guest->dom_id, path);
+		if (gntnode == NULL)
+			goto err;
+
+		if (parse_mpool_va(mempool))
+			goto err;
+
+		RTE_LOG(INFO, XENHOST, "  %s: mempool %u map gntnode %s\n", __func__, guest->pool_num, path);
+		if (map_mempoolnode(gntnode, mempool))
+			goto err;
+
+		xen_free_gntnode(gntnode);
+		guest->pool_num++;
+	}
+
+	return 0;
+err:
+	if (gntnode)
+		xen_free_gntnode(gntnode);
+	for (i = 0; i <  MAX_XENVIRT_MEMPOOL ; i++) {
+		cleanup_mempool(&guest->mempool[i]);
+	}
+	/* reinitialise mempool */
+	bzero(&guest->mempool, MAX_XENVIRT_MEMPOOL * sizeof(guest->mempool[0]));
+	return -1;
+}
+
+static int
+xen_map_vringflag(struct xen_vring *vring)
+{
+	char path[PATH_MAX] = {0};
+	char *buf;
+	uint32_t len,gref;
+	int pg_sz = getpagesize();
+	char *end;
+
+	snprintf(path, sizeof(path),
+		XEN_VM_ROOTNODE_FMT"/%d_"XEN_VRINGFLAG_SUFFIX,
+		vring->dom_id, vring->virtio_idx);
+
+	if((buf = xen_read_node(path, &len)) == NULL)
+		goto err;
+
+	errno = 0;
+	gref = strtol(buf, &end, 0);
+	if (errno != 0 || end == NULL || end == buf) {
+		goto err;
+	}
+	vring->flag = xen_grant_mmap(0, vring->dom_id, gref, &vring->flag_index);
+	if (vring->flag == NULL || *vring->flag == 0)
+		goto err;
+
+	free(buf);
+	return 0;
+err:
+	free(buf);
+	if (vring->flag) {
+		munmap(vring->flag, pg_sz);
+		vring->flag = NULL;
+		xen_unmap_grant_ref(vring->flag_index);
+	}
+	return -1;
+}
+
+
+static int
+xen_map_rxvringnode(struct xen_gntnode *gntnode,
+				struct xen_vring *vring)
+{
+	vring->rxvring_addr =
+		map_gntnode(gntnode, vring->dom_id, &vring->rxpfn_tbl, &vring->rxpfn_num, &vring->rx_pindex);
+	RTE_LOG(INFO, XENHOST, "  %s: map rx vring at %p\n", __func__, (void *)vring->rxvring_addr);
+	if (vring->rxvring_addr)
+		return 0;
+	else
+		return -1;
+}
+
+static int
+xen_map_txvringnode(struct xen_gntnode *gntnode,
+				struct xen_vring *vring)
+{
+	vring->txvring_addr =
+		map_gntnode(gntnode, vring->dom_id, &vring->txpfn_tbl, &vring->txpfn_num, &vring->tx_pindex);
+	RTE_LOG(INFO, XENHOST, "  %s: map tx vring at %p\n", __func__, (void *)vring->txvring_addr);
+	if (vring->txvring_addr)
+		return 0;
+	else
+		return -1;
+}
+
+void
+cleanup_vring(struct xen_vring *vring)
+{
+	int pg_sz = getpagesize();
+	uint32_t i;
+
+	RTE_LOG(INFO, XENHOST, "  %s: cleanup dom %u vring %u\n", __func__, vring->dom_id, vring->virtio_idx);
+	if (vring->rxvring_addr) {
+		munmap(vring->rxvring_addr, vring->rxpfn_num * pg_sz);
+		RTE_LOG(INFO, XENHOST, "  %s: unmap rx vring [%p, %p]\n",
+			__func__,
+			vring->rxvring_addr,
+			RTE_PTR_ADD(vring->rxvring_addr,
+			vring->rxpfn_num * pg_sz - 1));
+	}
+	vring->rxvring_addr = NULL;
+
+
+	if (vring->rx_pindex) {
+		RTE_LOG(INFO, XENHOST, "  %s: unmap rx vring %u grefs\n", __func__, vring->rxpfn_num);
+		for (i = 0; i < vring->rxpfn_num; i++) {
+			xen_unmap_grant_ref(vring->rx_pindex[i]);
+		}
+	}
+	vring->rx_pindex = NULL;
+
+	free(vring->rxpfn_tbl);
+	vring->rxpfn_tbl = NULL;
+
+	if (vring->txvring_addr) {
+		munmap(vring->txvring_addr, vring->txpfn_num * pg_sz);
+		RTE_LOG(INFO, XENHOST, "  %s: unmap tx vring [%p, %p]\n",
+			__func__,
+			vring->txvring_addr,
+			RTE_PTR_ADD(vring->txvring_addr,
+			vring->txpfn_num * pg_sz - 1));
+	}
+	vring->txvring_addr = NULL;
+
+	if (vring->tx_pindex) {
+		RTE_LOG(INFO, XENHOST, "  %s: unmap tx vring %u grefs\n", __func__, vring->txpfn_num);
+		for (i = 0; i < vring->txpfn_num; i++) {
+			xen_unmap_grant_ref(vring->tx_pindex[i]);
+		}
+	}
+	vring->tx_pindex = NULL;
+
+	free(vring->txpfn_tbl);
+	vring->txpfn_tbl = NULL;
+
+	if (vring->flag) {
+		if (!munmap((void *)vring->flag, pg_sz))
+			RTE_LOG(INFO, XENHOST, "  %s: unmap flag page at %p\n", __func__, vring->flag);
+		if (!xen_unmap_grant_ref(vring->flag_index))
+			RTE_LOG(INFO, XENHOST, "  %s: release flag ref index 0x%" PRIx64 "\n", __func__, vring->flag_index);
+	}
+	vring->flag = NULL;
+	return;
+}
+
+
+
+static int
+xen_parse_etheraddr(struct xen_vring *vring)
+{
+	char path[PATH_MAX] = {0};
+	char *buf;
+	uint32_t len;
+	int ret = -1;
+
+	snprintf(path, sizeof(path),
+		XEN_VM_ROOTNODE_FMT"/%d_"XEN_ADDR_SUFFIX,
+		vring->dom_id, vring->virtio_idx);
+
+	if ((buf = xen_read_node(path, &len)) == NULL)
+		goto out;
+
+	if (cmdline_parse_etheraddr(NULL, buf, &vring->addr,
+			sizeof(vring->addr)) < 0)
+		goto out;
+	ret = 0;
+out:
+	free(buf);
+	return ret;
+}
+
+
+int
+parse_vringnode(struct xen_guest *guest, uint32_t virtio_idx)
+{
+	char path[PATH_MAX] = {0};
+	struct xen_gntnode *rx_gntnode = NULL;
+	struct xen_gntnode *tx_gntnode = NULL;
+	struct xen_vring *vring = NULL;
+
+	/*check if null terminated */
+	snprintf(path, sizeof(path),
+		XEN_VM_ROOTNODE_FMT"/%d_"XEN_RXVRING_SUFFIX,
+		guest->dom_id,
+		virtio_idx);
+
+	RTE_LOG(INFO, XENHOST, "  %s: virtio %u parse rx gntnode %s\n", __func__, virtio_idx, path);
+	rx_gntnode = parse_gntnode(guest->dom_id, path);
+	if (rx_gntnode == NULL)
+		goto err;
+
+	/*check if null terminated */
+	snprintf(path, sizeof(path),
+		XEN_VM_ROOTNODE_FMT"/%d_"XEN_TXVRING_SUFFIX,
+		guest->dom_id,
+		virtio_idx);
+
+	RTE_LOG(INFO, XENHOST, "  %s: virtio %u parse tx gntnode %s\n", __func__, virtio_idx, path);
+	tx_gntnode = parse_gntnode(guest->dom_id, path);
+	if (tx_gntnode == NULL)
+		goto err;
+
+	vring = &guest->vring[virtio_idx];
+	bzero(vring, sizeof(*vring));
+	vring->dom_id = guest->dom_id;
+	vring->virtio_idx = virtio_idx;
+
+	if (xen_parse_etheraddr(vring) != 0)
+		goto err;
+
+	RTE_LOG(INFO, XENHOST, "  %s: virtio %u map rx gntnode %s\n", __func__, virtio_idx, path);
+	if (xen_map_rxvringnode(rx_gntnode, vring) != 0)
+		goto err;
+
+	RTE_LOG(INFO, XENHOST, "  %s: virtio %u map tx gntnode %s\n", __func__, virtio_idx, path);
+	if (xen_map_txvringnode(tx_gntnode, vring) != 0)
+		goto err;
+
+	if (xen_map_vringflag(vring) != 0)
+		goto err;
+
+	guest->vring_num++;
+
+	xen_free_gntnode(rx_gntnode);
+	xen_free_gntnode(tx_gntnode);
+
+	return 0;
+
+err:
+	if (rx_gntnode)
+		xen_free_gntnode(rx_gntnode);
+	if (tx_gntnode)
+		xen_free_gntnode(tx_gntnode);
+	if (vring) {
+		cleanup_vring(vring);
+		bzero(vring, sizeof(*vring));
+	}
+	return -1;
+}
+
+/*
+ * Open xen grant dev driver
+ * @return
+ *  0 on success, -1 on failure.
+ */
+static int
+xen_grant_init(void)
+{
+	d_fd = open(XEN_GNTDEV_FNAME, O_RDWR);
+
+	return d_fd == -1? (-1): (0);
+}
+
+/*
+ * Initialise xenstore handle and open grant dev driver.
+ * @return
+ *  0 on success, -1 on failure.
+ */
+int
+xenhost_init(void)
+{
+	xs = xs_daemon_open();
+	if (xs == NULL) {
+		rte_panic("failed initialize xen daemon handler");
+		return -1;
+	}
+	if (xen_grant_init())
+		return -1;
+	return 0;
+}