postcopy: Plumb pagesize down into place helpers

Now we deal with normal size pages and huge pages we need
to tell the place handlers the size we're dealing with
and make sure the temporary page is large enough.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20170224182844.32452-8-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

1 files changed, 28 insertions, 19 deletions

diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index 1e3d22fddc..a8b7fedc99 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -321,7 +321,7 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)
     migrate_send_rp_shut(mis, qemu_file_get_error(mis->from_src_file) != 0);
 
     if (mis->postcopy_tmp_page) {
-        munmap(mis->postcopy_tmp_page, getpagesize());
+        munmap(mis->postcopy_tmp_page, mis->largest_page_size);
         mis->postcopy_tmp_page = NULL;
     }
     trace_postcopy_ram_incoming_cleanup_exit();
@@ -543,13 +543,14 @@ int postcopy_ram_enable_notify(MigrationIncomingState *mis)
  * Place a host page (from) at (host) atomically
  * returns 0 on success
  */
-int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from)
+int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from,
+                        size_t pagesize)
 {
     struct uffdio_copy copy_struct;
 
     copy_struct.dst = (uint64_t)(uintptr_t)host;
     copy_struct.src = (uint64_t)(uintptr_t)from;
-    copy_struct.len = getpagesize();
+    copy_struct.len = pagesize;
     copy_struct.mode = 0;
 
     /* copy also acks to the kernel waking the stalled thread up
@@ -559,8 +560,8 @@ int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from)
      */
     if (ioctl(mis->userfault_fd, UFFDIO_COPY, &copy_struct)) {
         int e = errno;
-        error_report("%s: %s copy host: %p from: %p",
-                     __func__, strerror(e), host, from);
+        error_report("%s: %s copy host: %p from: %p (size: %zd)",
+                     __func__, strerror(e), host, from, pagesize);
 
         return -e;
     }
@@ -573,23 +574,29 @@ int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from)
  * Place a zero page at (host) atomically
  * returns 0 on success
  */
-int postcopy_place_page_zero(MigrationIncomingState *mis, void *host)
+int postcopy_place_page_zero(MigrationIncomingState *mis, void *host,
+                             size_t pagesize)
 {
-    struct uffdio_zeropage zero_struct;
+    trace_postcopy_place_page_zero(host);
 
-    zero_struct.range.start = (uint64_t)(uintptr_t)host;
-    zero_struct.range.len = getpagesize();
-    zero_struct.mode = 0;
+    if (pagesize == getpagesize()) {
+        struct uffdio_zeropage zero_struct;
+        zero_struct.range.start = (uint64_t)(uintptr_t)host;
+        zero_struct.range.len = getpagesize();
+        zero_struct.mode = 0;
 
-    if (ioctl(mis->userfault_fd, UFFDIO_ZEROPAGE, &zero_struct)) {
-        int e = errno;
-        error_report("%s: %s zero host: %p",
-                     __func__, strerror(e), host);
+        if (ioctl(mis->userfault_fd, UFFDIO_ZEROPAGE, &zero_struct)) {
+            int e = errno;
+            error_report("%s: %s zero host: %p",
+                         __func__, strerror(e), host);
 
-        return -e;
+            return -e;
+        }
+    } else {
+        /* TODO: The kernel can't use UFFDIO_ZEROPAGE for hugepages */
+        assert(0);
     }
 
-    trace_postcopy_place_page_zero(host);
     return 0;
 }
 
@@ -604,7 +611,7 @@ int postcopy_place_page_zero(MigrationIncomingState *mis, void *host)
 void *postcopy_get_tmp_page(MigrationIncomingState *mis)
 {
     if (!mis->postcopy_tmp_page) {
-        mis->postcopy_tmp_page = mmap(NULL, getpagesize(),
+        mis->postcopy_tmp_page = mmap(NULL, mis->largest_page_size,
                              PROT_READ | PROT_WRITE, MAP_PRIVATE |
                              MAP_ANONYMOUS, -1, 0);
         if (mis->postcopy_tmp_page == MAP_FAILED) {
@@ -649,13 +656,15 @@ int postcopy_ram_enable_notify(MigrationIncomingState *mis)
     return -1;
 }
 
-int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from)
+int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from,
+                        size_t pagesize)
 {
     assert(0);
     return -1;
 }
 
-int postcopy_place_page_zero(MigrationIncomingState *mis, void *host)
+int postcopy_place_page_zero(MigrationIncomingState *mis, void *host,
+                        size_t pagesize)
 {
     assert(0);
     return -1;