Index: sys/dev/iommu/iommu.h
===================================================================
--- sys/dev/iommu/iommu.h
+++ sys/dev/iommu/iommu.h
@@ -100,6 +100,13 @@
 	uint32_t buswide_ctxs[(PCI_BUSMAX + 1) / NBBY / sizeof(uint32_t)];
 };
 
+struct iommu_domain_map_ops {
+	int (*map)(struct iommu_domain *domain, iommu_gaddr_t base,
+	    iommu_gaddr_t size, vm_page_t *ma, uint64_t pflags, int flags);
+	int (*unmap)(struct iommu_domain *domain, iommu_gaddr_t base,
+	    iommu_gaddr_t size, int flags);
+};
+
 /*
  * Locking annotations:
  * (u) - Protected by iommu unit lock
@@ -109,6 +116,7 @@
 
 struct iommu_domain {
 	struct iommu_unit *iommu;	/* (c) */
+	struct iommu_domain_map_ops ops;
 	struct mtx lock;		/* (c) */
 	struct task unload_task;	/* (c) */
 	u_int entries_cnt;		/* (d) */
Index: sys/dev/iommu/iommu_gas.c
===================================================================
--- sys/dev/iommu/iommu_gas.c
+++ sys/dev/iommu/iommu_gas.c
@@ -66,10 +66,7 @@
 #include <machine/bus.h>
 #include <machine/md_var.h>
 #if defined(__amd64__) || defined(__i386__)
-#include <machine/specialreg.h>
-#include <x86/include/busdma_impl.h>
 #include <x86/iommu/intel_reg.h>
-#include <x86/iommu/intel_dmar.h>
 #endif
 #include <dev/iommu/busdma_iommu.h>
 
@@ -620,7 +617,7 @@
 	entry->flags |= eflags;
 	IOMMU_DOMAIN_UNLOCK(domain);
 
-	error = domain_map_buf(domain, entry->start, entry->end - entry->start,
+	error = domain->ops.map(domain, entry->start, entry->end - entry->start,
 	    ma, eflags,
 	    ((flags & IOMMU_MF_CANWAIT) != 0 ? IOMMU_PGF_WAITOK : 0));
 	if (error == ENOMEM) {
@@ -658,7 +655,7 @@
 	if (entry->end == entry->start)
 		return (0);
 
-	error = domain_map_buf(domain, entry->start, entry->end - entry->start,
+	error = domain->ops.map(domain, entry->start, entry->end - entry->start,
 	    ma + OFF_TO_IDX(start - entry->start), eflags,
 	    ((flags & IOMMU_MF_CANWAIT) != 0 ? IOMMU_PGF_WAITOK : 0));
 	if (error == ENOMEM) {
Index: sys/x86/iommu/intel_ctx.c
===================================================================
--- sys/x86/iommu/intel_ctx.c
+++ sys/x86/iommu/intel_ctx.c
@@ -342,6 +342,9 @@
 	domain->dmar = dmar;
 	domain->iodom.iommu = &dmar->iommu;
 
+	iodom->ops.map = domain_map_buf;
+	iodom->ops.unmap = domain_unmap_buf;
+
 	/*
 	 * For now, use the maximal usable physical address of the
 	 * installed memory to calculate the mgaw on id_mapped domain.
@@ -842,15 +845,17 @@
     struct iommu_map_entries_tailq *entries, bool cansleep)
 {
 	struct dmar_unit *unit;
+	struct iommu_domain *iodom;
 	struct iommu_map_entry *entry, *entry1;
 	int error;
 
+	iodom = (struct iommu_domain *)domain;
 	unit = (struct dmar_unit *)domain->iodom.iommu;
 
 	TAILQ_FOREACH_SAFE(entry, entries, dmamap_link, entry1) {
 		KASSERT((entry->flags & IOMMU_MAP_ENTRY_MAP) != 0,
 		    ("not mapped entry %p %p", domain, entry));
-		error = domain_unmap_buf(domain, entry->start, entry->end -
+		error = iodom->ops.unmap(iodom, entry->start, entry->end -
 		    entry->start, cansleep ? IOMMU_PGF_WAITOK : 0);
 		KASSERT(error == 0, ("unmap %p error %d", domain, error));
 		if (!unit->qi_enabled) {
Index: sys/x86/iommu/intel_dmar.h
===================================================================
--- sys/x86/iommu/intel_dmar.h
+++ sys/x86/iommu/intel_dmar.h
@@ -246,7 +246,7 @@
 void put_idmap_pgtbl(vm_object_t obj);
 int domain_map_buf(struct iommu_domain *domain, iommu_gaddr_t base,
     iommu_gaddr_t size, vm_page_t *ma, uint64_t pflags, int flags);
-int domain_unmap_buf(struct dmar_domain *domain, iommu_gaddr_t base,
+int domain_unmap_buf(struct iommu_domain *domain, iommu_gaddr_t base,
     iommu_gaddr_t size, int flags);
 void domain_flush_iotlb_sync(struct dmar_domain *domain, iommu_gaddr_t base,
     iommu_gaddr_t size);
Index: sys/x86/iommu/intel_idpgtbl.c
===================================================================
--- sys/x86/iommu/intel_idpgtbl.c
+++ sys/x86/iommu/intel_idpgtbl.c
@@ -685,11 +685,14 @@
 }
 
 int
-domain_unmap_buf(struct dmar_domain *domain, iommu_gaddr_t base,
+domain_unmap_buf(struct iommu_domain *iodom, iommu_gaddr_t base,
     iommu_gaddr_t size, int flags)
 {
+	struct dmar_domain *domain;
 	int error;
 
+	domain = (struct dmar_domain *)iodom;
+
 	DMAR_DOMAIN_PGLOCK(domain);
 	error = domain_unmap_buf_locked(domain, base, size, flags);
 	DMAR_DOMAIN_PGUNLOCK(domain);