Mark send and receive buffers as shared and unowned.
These buffers are now controlled by and shared with the hypervisor.
Change-Id: Iecd5733141e12bccb3995357231ea3feae6ce36a
diff --git a/src/api.c b/src/api.c
index a804a11..ae03306 100644
--- a/src/api.c
+++ b/src/api.c
@@ -273,7 +273,9 @@
paddr_t pa_send_end;
paddr_t pa_recv_begin;
paddr_t pa_recv_end;
- int mode;
+ int orig_send_mode;
+ int orig_recv_mode;
+ struct mpool local_page_pool;
int64_t ret;
/* Fail if addresses are not page-aligned. */
@@ -282,29 +284,6 @@
return -1;
}
- sl_lock(&vm->lock);
-
- /* We only allow these to be setup once. */
- if (vm->mailbox.send || vm->mailbox.recv) {
- ret = -1;
- goto exit;
- }
-
- /* Ensure the pages are valid, owned and exclusive to the VM. */
- if (!mm_vm_get_mode(&vm->ptable, send, ipa_add(send, PAGE_SIZE),
- &mode) ||
- !api_mode_valid_owned_and_exclusive(mode)) {
- ret = -1;
- goto exit;
- }
-
- if (!mm_vm_get_mode(&vm->ptable, recv, ipa_add(recv, PAGE_SIZE),
- &mode) ||
- !api_mode_valid_owned_and_exclusive(mode)) {
- 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);
@@ -314,16 +293,67 @@
/* 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;
+ return -1;
+ }
+
+ sl_lock(&vm->lock);
+
+ /* We only allow these to be setup once. */
+ if (vm->mailbox.send || vm->mailbox.recv) {
+ goto fail;
+ }
+
+ /*
+ * Ensure the pages are valid, owned and exclusive to the VM and that
+ * the VM has the required access to the memory.
+ */
+ if (!mm_vm_get_mode(&vm->ptable, send, ipa_add(send, PAGE_SIZE),
+ &orig_send_mode) ||
+ !api_mode_valid_owned_and_exclusive(orig_send_mode) ||
+ (orig_send_mode & MM_MODE_R) == 0 ||
+ (orig_send_mode & MM_MODE_W) == 0) {
+ goto fail;
+ }
+
+ if (!mm_vm_get_mode(&vm->ptable, recv, ipa_add(recv, PAGE_SIZE),
+ &orig_recv_mode) ||
+ !api_mode_valid_owned_and_exclusive(orig_recv_mode) ||
+ (orig_recv_mode & MM_MODE_R) == 0) {
+ goto fail;
+ }
+
+ /*
+ * Create a local pool so any freed memory can't be used by another
+ * thread. This is to ensure the original mapping can be restored if any
+ * stage of the process fails.
+ */
+ mpool_init_with_fallback(&local_page_pool, &api_page_pool);
+
+ /* Take memory ownership away from the VM and mark as shared. */
+ if (!mm_vm_identity_map(
+ &vm->ptable, pa_send_begin, pa_send_end,
+ MM_MODE_UNOWNED | MM_MODE_SHARED | MM_MODE_R | MM_MODE_W,
+ NULL, &local_page_pool)) {
+ goto fail_free_pool;
+ }
+
+ if (!mm_vm_identity_map(&vm->ptable, pa_recv_begin, pa_recv_end,
+ MM_MODE_UNOWNED | MM_MODE_SHARED | MM_MODE_R,
+ NULL, &local_page_pool)) {
+ /* TODO: partial defrag of failed range. */
+ /* Recover any memory consumed in failed mapping. */
+ mm_ptable_defrag(&vm->ptable, 0, &local_page_pool);
+ goto fail_undo_send;
}
/* 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);
+ MM_MODE_R, &local_page_pool);
if (!vm->mailbox.send) {
- ret = -1;
- goto exit;
+ /* TODO: partial defrag of failed range. */
+ /* Recover any memory consumed in failed mapping. */
+ mm_defrag(&local_page_pool);
+ goto fail_undo_send_and_recv;
}
/*
@@ -331,17 +361,41 @@
* failure, unmap the send page before returning.
*/
vm->mailbox.recv = mm_identity_map(pa_recv_begin, pa_recv_end,
- MM_MODE_W, &api_page_pool);
+ MM_MODE_W, &local_page_pool);
if (!vm->mailbox.recv) {
- vm->mailbox.send = NULL;
- mm_unmap(pa_send_begin, pa_send_end, 0, &api_page_pool);
- ret = -1;
- goto exit;
+ /* TODO: partial defrag of failed range. */
+ /* Recover any memory consumed in failed mapping. */
+ mm_defrag(&local_page_pool);
+ goto fail_undo_all;
}
/* TODO: Notify any waiters. */
ret = 0;
+ goto exit;
+
+ /*
+ * The following mappings will not require more memory than is available
+ * in the local pool.
+ */
+fail_undo_all:
+ vm->mailbox.send = NULL;
+ mm_unmap(pa_send_begin, pa_send_end, 0, &local_page_pool);
+
+fail_undo_send_and_recv:
+ mm_vm_identity_map(&vm->ptable, pa_recv_begin, pa_recv_end,
+ orig_recv_mode, NULL, &local_page_pool);
+
+fail_undo_send:
+ mm_vm_identity_map(&vm->ptable, pa_send_begin, pa_send_end,
+ orig_send_mode, NULL, &local_page_pool);
+
+fail_free_pool:
+ mpool_fini(&local_page_pool);
+
+fail:
+ ret = -1;
+
exit:
sl_unlock(&vm->lock);
