--- b/sys/amd64/vmm/io/ppt.c	
+++ b/sys/amd64/vmm/io/ppt.c	
@@ -452,8 +452,11 @@ ppt_map_mmio(struct vm *vm, int bus, int slot, int func,
 	struct pptseg *seg;
 	struct pptdev *ppt;
 
+bool mine = gpa == 0xd0000000;
+if (mine) printf("ppt_map_mmio: pci0:%d:%d:%d\n", bus, slot, func);
 	ppt = ppt_find(bus, slot, func);
 	if (ppt != NULL) {
+ if (ppt->vm != vm && mine) printf("ppt_map_mmio: EBUSY\n");
 		if (ppt->vm != vm)
 			return (EBUSY);
 
@@ -465,11 +468,14 @@ ppt_map_mmio(struct vm *vm, int bus, int slot, int func,
 					seg->gpa = gpa;
 					seg->len = len;
 				}
+if (mine) printf("ppt_map_mmio: vm_map_mmio %d\n", error);
 				return (error);
 			}
 		}
+if (mine) printf("ppt_map_mmio: ENOSPC\n");
 		return (ENOSPC);
 	}
+if (mine) printf("ppt_map_mmio: ENOENT\n");
 	return (ENOENT);
 }
 
--- b/sys/amd64/vmm/vmm.c	
+++ b/sys/amd64/vmm/vmm.c	
@@ -650,6 +650,7 @@ vm_mem_allocated(struct vm *vm, int vcpuid, vm_paddr_t gpa)
 			return (true);		/* 'gpa' is sysmem or devmem */
 	}
 
+if (gpa >= 0xd0000000 && gpa < 0xe0000000) printf("ppt_is_mmio %#lx %d\n", gpa, ppt_is_mmio(vm, gpa));
 	if (ppt_is_mmio(vm, gpa))
 		return (true);			/* 'gpa' is pci passthru mmio */