Quit pretending that IPAs aren't identity mapped.
Information about memory sharing will be stored in the page table
entries rather than introducing a new data structure as that adds
complexity and new potential for memory management issues.
The information includes tracking whether memory is owned by a VM. If a
region of memory is borrowed by another, the memory can only be passed
back the the owner and this is checked by looking in the page table.
Identity mapping is needed so we know where to look in the table as,
otherwise, searching for a physical address is impractical.
Change-Id: I417376b3ecd31bc07518ac5c51b9fb7df2f4b3e1
diff --git a/src/api.c b/src/api.c
index 7cbe1b1..4ab7416 100644
--- a/src/api.c
+++ b/src/api.c
@@ -212,26 +212,26 @@
* these pages aren't and won't be shared.
*/
- /*
- * Convert the intermediate physical addresses to physical address
- * provided the address was acessible from the VM which ensures that the
- * caller isn't trying to use another VM's memory.
- */
- if (!mm_vm_translate(&vm->ptable, send, &pa_send_begin) ||
- !mm_vm_translate(&vm->ptable, recv, &pa_recv_begin)) {
+ /* Ensure the pages are accessible from the VM. */
+ if (!mm_vm_is_mapped(&vm->ptable, send, 0) ||
+ !mm_vm_is_mapped(&vm->ptable, recv, 0)) {
ret = -1;
goto exit;
}
+ /* Convert to physical addresses. */
+ pa_send_begin = pa_from_ipa(send);
+ pa_send_end = pa_add(pa_send_begin, PAGE_SIZE);
+
+ pa_recv_begin = pa_from_ipa(recv);
+ pa_recv_end = pa_add(pa_recv_begin, PAGE_SIZE);
+
/* Fail if the same page is used for the send and receive pages. */
if (pa_addr(pa_send_begin) == pa_addr(pa_recv_begin)) {
ret = -1;
goto exit;
}
- pa_send_end = pa_add(pa_send_begin, PAGE_SIZE);
- pa_recv_end = pa_add(pa_recv_begin, PAGE_SIZE);
-
/* Map the send page as read-only in the hypervisor address space. */
vm->mailbox.send = mm_identity_map(pa_send_begin, pa_send_end,
MM_MODE_R, &api_page_pool);