Commit d2f39add authored by Dominik Dingel's avatar Dominik Dingel Committed by Paolo Bonzini
Browse files

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: default avatarHalil Pasic <pasic@linux.vnet.ibm.com>
Signed-off-by: default avatarDominik Dingel <dingel@linux.vnet.ibm.com>

Message-Id: <1461585338-45863-1-git-send-email-dingel@linux.vnet.ibm.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent e081c24d

exec.c

+3 −2
Original line number Diff line number Diff line
@@ -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");

include/qemu/osdep.h

+13 −0
Original line number Diff line number Diff line
@@ -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, ...);

util/oslib-posix.c

+0 −13
Original line number Diff line number Diff line
@@ -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>