diff --git a/lib/librte_eal/common/include/rte_memory.h b/lib/librte_eal/common/include/rte_memory.h
index f8dbece004..06611093f4 100644
--- a/lib/librte_eal/common/include/rte_memory.h
+++ b/lib/librte_eal/common/include/rte_memory.h
@@ -200,21 +200,22 @@ unsigned rte_memory_get_nrank(void);
 int rte_xen_dom0_supported(void);
 
 /**< Internal use only - phys to virt mapping for xen */
-phys_addr_t rte_xen_mem_phy2mch(uint32_t, const phys_addr_t);
+phys_addr_t rte_xen_mem_phy2mch(int32_t, const phys_addr_t);
 
 /**
  * Return the physical address of elt, which is an element of the pool mp.
  *
  * @param memseg_id
- *   The mempool is from which memory segment.
+ *   Identifier of the memory segment owning the physical address. If
+ *   set to -1, find it automatically.
  * @param phy_addr
  *   physical address of elt.
  *
  * @return
- *   The physical address or error.
+ *   The physical address or RTE_BAD_PHYS_ADDR on error.
  */
 static inline phys_addr_t
-rte_mem_phy2mch(uint32_t memseg_id, const phys_addr_t phy_addr)
+rte_mem_phy2mch(int32_t memseg_id, const phys_addr_t phy_addr)
 {
 	if (rte_xen_dom0_supported())
 		return rte_xen_mem_phy2mch(memseg_id, phy_addr);
@@ -250,7 +251,7 @@ static inline int rte_xen_dom0_supported(void)
 }
 
 static inline phys_addr_t
-rte_mem_phy2mch(uint32_t memseg_id __rte_unused, const phys_addr_t phy_addr)
+rte_mem_phy2mch(int32_t memseg_id __rte_unused, const phys_addr_t phy_addr)
 {
 	return phy_addr;
 }
diff --git a/lib/librte_eal/linuxapp/eal/eal_xen_memory.c b/lib/librte_eal/linuxapp/eal/eal_xen_memory.c
index 495eef9e72..0b612bb1f4 100644
--- a/lib/librte_eal/linuxapp/eal/eal_xen_memory.c
+++ b/lib/librte_eal/linuxapp/eal/eal_xen_memory.c
@@ -156,13 +156,27 @@ get_xen_memory_size(void)
  * Based on physical address to caculate MFN in Xen Dom0.
  */
 phys_addr_t
-rte_xen_mem_phy2mch(uint32_t memseg_id, const phys_addr_t phy_addr)
+rte_xen_mem_phy2mch(int32_t memseg_id, const phys_addr_t phy_addr)
 {
-	int mfn_id;
+	int mfn_id, i;
 	uint64_t mfn, mfn_offset;
 	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
 	struct rte_memseg *memseg = mcfg->memseg;
 
+	/* find the memory segment owning the physical address */
+	if (memseg_id == -1) {
+		for (i = 0; i < RTE_MAX_MEMSEG; i++) {
+			if ((phy_addr >= memseg[i].phys_addr) &&
+					(phys_addr < memseg[i].phys_addr +
+						memseg[i].size)) {
+				memseg_id = i;
+				break;
+			}
+		}
+		if (memseg_id == -1)
+			return RTE_BAD_PHYS_ADDR;
+	}
+
 	mfn_id = (phy_addr - memseg[memseg_id].phys_addr) / RTE_PGSIZE_2M;
 
 	/*the MFN is contiguous in 2M */