exec.c: Ensure right alignment also for file backed ram

While in the anonymous ram case we already take care of the right alignment
such an alignment gurantee does not exist for file backed ram allocation.

Instead, pagesize is used for alignment. On s390 this is not enough for gmap,
as we need to satisfy an alignment up to segments.

Reported-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Message-Id: <1461585338-45863-1-git-send-email-dingel@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/exec.c b/exec.c
index 2e363f06a6bf041b94bee0a392a3f85f39a78d23..59aed1782812953a4262fa23edcd24d58556d5dc 100644 (file)
--- a/exec.c
+++ b/exec.c
@@ -1299,7 +1299,7 @@ static void *file_ram_alloc(RAMBlock *block,
     }
 
     page_size = qemu_fd_getpagesize(fd);
-    block->mr->align = page_size;
+    block->mr->align = MAX(page_size, QEMU_VMALLOC_ALIGN);
 
     if (memory < page_size) {
         error_setg(errp, "memory size 0x" RAM_ADDR_FMT " must be equal to "
@@ -1320,7 +1320,8 @@ static void *file_ram_alloc(RAMBlock *block,
         perror("ftruncate");
     }
 
-    area = qemu_ram_mmap(fd, memory, page_size, block->flags & RAM_SHARED);
+    area = qemu_ram_mmap(fd, memory, block->mr->align,
+                         block->flags & RAM_SHARED);
     if (area == MAP_FAILED) {
         error_setg_errno(errp, errno,
                          "unable to map backing store for guest RAM");

diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 268ec669589b20e235a36522d163ba83ccc37125..994bfa023aced7fe88b039a114efd0a4c708e910 100644 (file)
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -263,6 +263,19 @@ void qemu_anon_ram_free(void *ptr, size_t size);
 
 #endif
 
+#if defined(__linux__) && \
+    (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__))
+   /* Use 2 MiB alignment so transparent hugepages can be used by KVM.
+      Valgrind does not support alignments larger than 1 MiB,
+      therefore we need special code which handles running on Valgrind. */
+#  define QEMU_VMALLOC_ALIGN (512 * 4096)
+#elif defined(__linux__) && defined(__s390x__)
+   /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */
+#  define QEMU_VMALLOC_ALIGN (256 * 4096)
+#else
+#  define QEMU_VMALLOC_ALIGN getpagesize()
+#endif
+
 int qemu_madvise(void *addr, size_t len, int advice);
 
 int qemu_open(const char *name, int flags, ...);

diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 6cc4b8f0010a58bed6589bcf3c49891b434bb78d..4adde93ac1aa12e5cded8167ff4d3cb2771285fd 100644 (file)
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -26,19 +26,6 @@
  * THE SOFTWARE.
  */
 
-#if defined(__linux__) && \
-    (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__))
-   /* Use 2 MiB alignment so transparent hugepages can be used by KVM.
-      Valgrind does not support alignments larger than 1 MiB,
-      therefore we need special code which handles running on Valgrind. */
-#  define QEMU_VMALLOC_ALIGN (512 * 4096)
-#elif defined(__linux__) && defined(__s390x__)
-   /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */
-#  define QEMU_VMALLOC_ALIGN (256 * 4096)
-#else
-#  define QEMU_VMALLOC_ALIGN getpagesize()
-#endif
-
 #include "qemu/osdep.h"
 #include <termios.h>
 #include <termios.h>