For rumpdisk to efficiently determine the physical address, both for
checking whether it is below 4GiB, and for giving it to the disk
driver, we need a gnumach primitive (and that is not conditioned by
MACH_VM_DEBUG like mach_vm_region_info and mach_vm_object_pages_phys
are).
---
Please notably review the RPC part, I really don't know that much about
mig.
diff --git a/i386/include/mach/i386/machine_types.defs b/i386/include/mach/i386/machine_types.defs
index 3d540be9..76c7dcf9 100755
--- a/i386/include/mach/i386/machine_types.defs
+++ b/i386/include/mach/i386/machine_types.defs
@@ -102,5 +102,6 @@ type long_integer_t = rpc_long_integer_t
* Physical address size
*/
type rpc_phys_addr_t = uint64_t;
+type rpc_phys_addr_array_t = array[] of rpc_phys_addr_t;
Looks good to me. I think array[] of rpc_phys_addr_t is the best choice here.
From my understanding, there's three ways to do arrays in mig:
- array[] of rpc_phys_addr_t;
This will pass up to 2048 bytes inlined in the message and anything bigger than that will be out of line. The user can pass a pre-existing array and mig will try to copy it if there's enough space. When the array is too big, the user gets a new pointer. In the function below, *countp will always be 256 initially (size of the inline array) and it is possible to allocate a new page if (*countp < count) so that the user will still get the results if there are more than 256 items.
- ^array[] of rpc_phys_addr;
Here everything is passed out of line. The user does need to pass an allocated array as the data will be passed out of line.
- array[*:128] of rpc_phys_addr;
This is only usable in case the maximum size is known ahead of time as everything is passed inline.
#endif /* _MACHINE_MACHINE_TYPES_DEFS_ */
diff --git a/i386/include/mach/i386/vm_types.h b/i386/include/mach/i386/vm_types.h
index bd07ef26..8f528ae1 100644
--- a/i386/include/mach/i386/vm_types.h
+++ b/i386/include/mach/i386/vm_types.h
@@ -94,6 +94,7 @@ typedef unsigned long phys_addr_t;
typedef unsigned long long phys_addr_t;
#endif
typedef unsigned long long rpc_phys_addr_t;
+typedef rpc_phys_addr_t *rpc_phys_addr_array_t;
/*
* A vm_size_t is the proper type for e.g.
diff --git a/include/mach/gnumach.defs b/include/mach/gnumach.defs
index 05101a48..6252de96 100644
--- a/include/mach/gnumach.defs
+++ b/include/mach/gnumach.defs
@@ -197,3 +197,13 @@ routine vm_allocate_contiguous(
simpleroutine task_set_essential(
task : task_t;
essential : boolean_t);
+
+/*
+ * Returns physical addresses of a region of memory
+ */
+routine vm_pages_phys(
+ host_priv : host_priv_t;
+ target_task : vm_task_t;
+ vaddr : vm_address_t;
+ size : vm_size_t;
+ out pages : rpc_phys_addr_array_t);
diff --git a/vm/vm_user.c b/vm/vm_user.c
index 08cc17a4..6c16c397 100644
--- a/vm/vm_user.c
+++ b/vm/vm_user.c
@@ -700,3 +700,90 @@ kern_return_t vm_allocate_contiguous(
return KERN_SUCCESS;
}
+
+/*
+ * vm_pages_phys returns information about a region of memory
+ */
+kern_return_t vm_pages_phys(
+ host_t host,
+ vm_map_t map,
+ vm_address_t address,
+ vm_size_t size,
+ rpc_phys_addr_array_t *pagespp,
+ mach_msg_type_number_t *countp)
+{
+ if (host == HOST_NULL)
+ return KERN_INVALID_HOST;
+ if (map == VM_MAP_NULL)
+ return KERN_INVALID_TASK;
+
+ if (!page_aligned(address))
+ return KERN_INVALID_ARGUMENT;
+ if (!page_aligned(size))
+ return KERN_INVALID_ARGUMENT;
+
+ mach_msg_type_number_t count = atop(size), cur;
+
+ if (*countp < count)
+ return KERN_INVALID_ARGUMENT;
+
+ rpc_phys_addr_array_t pagesp = *pagespp;
+
+ for (cur = 0; cur < count; cur++)
+ {
+ vm_map_t cmap; /* current map in traversal */
+ rpc_phys_addr_t paddr;
+ vm_map_entry_t entry; /* entry in current map */
+
+ /* find the entry containing (or following) the address */
+ vm_map_lock_read(map);
+ for (cmap = map;;) {
+ /* cmap is read-locked */
+
+ if (!vm_map_lookup_entry(cmap, address, &entry)) {
+ entry = VM_MAP_ENTRY_NULL;
+ break;
+ }
+
+ if (entry->is_sub_map) {
+ /* move down to the sub map */
+
+ vm_map_t nmap = entry->object.sub_map;
+ vm_map_lock_read(nmap);
+ vm_map_unlock_read(cmap);
+ cmap = nmap;
+ continue;
+ } else {
+ /* Found it */
+ break;
+ }
+ /*NOTREACHED*/
+ }
+
+ paddr = 0;
+ if (entry)
+ {
+ vm_offset_t offset = address - entry->vme_start + entry->offset;
+ vm_object_t object = entry->object.vm_object;
+
+ if (object) {
+ vm_object_lock(object);
+ vm_page_t page = vm_page_lookup(object, offset);
+ if (page) {
+ if (page->phys_addr != (typeof(pagesp[cur])) page->phys_addr)
+ printf("warning: physical address overflow in vm_pages_phys!!\n");
+ else
+ paddr = page->phys_addr;
+ }
+ vm_object_unlock(object);
+ }
+ }
+ vm_map_unlock_read(cmap);
+ pagesp[cur] = paddr;
+
+ address += PAGE_SIZE;
+ }
+ *countp = count;
+
+ return KERN_SUCCESS;
+}