[Qemu-devel] [PATCH v2 11/16] postcopy: Mask fault addresses to huge page boundary

["Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

Currently the fault address received by userfault is rounded to
the host page boundary and a host page is requested from the source.
Use the current RAMBlock page size instead of the general host page
size so that for RAMBlocks backed by huge pages we request the whole
huge page.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
---
 include/exec/memory.h    | 1 -
 migration/postcopy-ram.c | 7 +++----
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 987f925..c428891 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -1614,7 +1614,6 @@ MemTxResult address_space_read_continue(AddressSpace *as, hwaddr addr,
 MemTxResult address_space_read_full(AddressSpace *as, hwaddr addr,
                                     MemTxAttrs attrs, uint8_t *buf, int len);
 void *qemu_map_ram_ptr(RAMBlock *ram_block, ram_addr_t addr);
-
 static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write)
 {
     if (is_write) {
diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index 4c736d2..03cbd6e 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -403,7 +403,6 @@ static void *postcopy_ram_fault_thread(void *opaque)
     MigrationIncomingState *mis = opaque;
     struct uffd_msg msg;
     int ret;
-    size_t hostpagesize = getpagesize();
     RAMBlock *rb = NULL;
     RAMBlock *last_rb = NULL; /* last RAMBlock we sent part of */
 
@@ -470,7 +469,7 @@ static void *postcopy_ram_fault_thread(void *opaque)
             break;
         }
 
-        rb_offset &= ~(hostpagesize - 1);
+        rb_offset &= ~(qemu_ram_pagesize(rb) - 1);
         trace_postcopy_ram_fault_thread_request(msg.arg.pagefault.address,
                                                 qemu_ram_get_idstr(rb),
                                                 rb_offset);
@@ -482,11 +481,11 @@ static void *postcopy_ram_fault_thread(void *opaque)
         if (rb != last_rb) {
             last_rb = rb;
             migrate_send_rp_req_pages(mis, qemu_ram_get_idstr(rb),
-                                     rb_offset, hostpagesize);
+                                     rb_offset, qemu_ram_pagesize(rb));
         } else {
             /* Save some space */
             migrate_send_rp_req_pages(mis, NULL,
-                                     rb_offset, hostpagesize);
+                                     rb_offset, qemu_ram_pagesize(rb));
         }
     }
     trace_postcopy_ram_fault_thread_exit();
-- 
2.9.3