memory: move preallocation code out of exec.c

So that backends can use it.

Since we need the page size for efficiency, move code to compute it
out of translate-all.c and into util/oslib-win32.c.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

exec.c

@@ -1011,13 +1011,6 @@ static long gethugepagesize(const char *path)
     return fs.f_bsize;
 }
 
-static sigjmp_buf sigjump;
-
-static void sigbus_handler(int signal)
-{
-    siglongjmp(sigjump, 1);
-}
-
 static void *file_ram_alloc(RAMBlock *block,
                             ram_addr_t memory,
                             const char *path)
@@ -1082,42 +1075,7 @@ static void *file_ram_alloc(RAMBlock *block,
     }
 
     if (mem_prealloc) {
-        int ret, i;
+        os_mem_prealloc(fd, area, memory);
-        struct sigaction act, oldact;
-        sigset_t set, oldset;
-
-        memset(&act, 0, sizeof(act));
-        act.sa_handler = &sigbus_handler;
-        act.sa_flags = 0;
-
-        ret = sigaction(SIGBUS, &act, &oldact);
-        if (ret) {
-            perror("file_ram_alloc: failed to install signal handler");
-            exit(1);
-        }
-
-        /* unblock SIGBUS */
-        sigemptyset(&set);
-        sigaddset(&set, SIGBUS);
-        pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
-
-        if (sigsetjmp(sigjump, 1)) {
-            fprintf(stderr, "file_ram_alloc: failed to preallocate pages\n");
-            exit(1);
-        }
-
-        /* MAP_POPULATE silently ignores failures */
-        for (i = 0; i < (memory/hpagesize); i++) {
-            memset(area + (hpagesize*i), 0, 1);
-        }
-
-        ret = sigaction(SIGBUS, &oldact, NULL);
-        if (ret) {
-            perror("file_ram_alloc: failed to reinstall signal handler");
-            exit(1);
-        }
-
-        pthread_sigmask(SIG_SETMASK, &oldset, NULL);
     }
 
     block->fd = fd;

include/qemu/osdep.h

@@ -251,4 +251,6 @@ void qemu_init_auxval(char **envp);
 
 void qemu_set_tty_echo(int fd, bool echo);
 
+void os_mem_prealloc(int fd, char *area, size_t sz);
+
 #endif

include/sysemu/os-win32.h

@@ -89,6 +89,8 @@ static inline void os_setup_post(void) {}
 void os_set_line_buffering(void);
 static inline void os_set_proc_name(const char *dummy) {}
 
+size_t getpagesize(void);
+
 #if !defined(EPROTONOSUPPORT)
 # define EPROTONOSUPPORT EINVAL
 #endif

translate-all.c

@@ -295,14 +295,7 @@ void page_size_init(void)
 {
     /* NOTE: we can always suppose that qemu_host_page_size >=
        TARGET_PAGE_SIZE */
-#ifdef _WIN32
-    SYSTEM_INFO system_info;
-
-    GetSystemInfo(&system_info);
-    qemu_real_host_page_size = system_info.dwPageSize;
-#else
     qemu_real_host_page_size = getpagesize();
-#endif
     if (qemu_host_page_size == 0) {
         qemu_host_page_size = qemu_real_host_page_size;
     }

util/oslib-posix.c

@@ -46,6 +46,7 @@ extern int daemon(int, int);
 #else
 #  define QEMU_VMALLOC_ALIGN getpagesize()
 #endif
+#define HUGETLBFS_MAGIC       0x958458f6
 
 #include <termios.h>
 #include <unistd.h>
@@ -58,9 +59,12 @@ extern int daemon(int, int);
 #include "qemu/sockets.h"
 #include <sys/mman.h>
 #include <libgen.h>
+#include <setjmp.h>
+#include <sys/signal.h>
 
 #ifdef CONFIG_LINUX
 #include <sys/syscall.h>
+#include <sys/vfs.h>
 #endif
 
 #ifdef __FreeBSD__
@@ -332,3 +336,72 @@ char *qemu_get_exec_dir(void)
 {
     return g_strdup(exec_dir);
 }
+
+static sigjmp_buf sigjump;
+
+static void sigbus_handler(int signal)
+{
+    siglongjmp(sigjump, 1);
+}
+
+static size_t fd_getpagesize(int fd)
+{
+#ifdef CONFIG_LINUX
+    struct statfs fs;
+    int ret;
+
+    if (fd != -1) {
+        do {
+            ret = fstatfs(fd, &fs);
+        } while (ret != 0 && errno == EINTR);
+
+        if (ret == 0 && fs.f_type == HUGETLBFS_MAGIC) {
+            return fs.f_bsize;
+        }
+    }
+#endif
+
+    return getpagesize();
+}
+
+void os_mem_prealloc(int fd, char *area, size_t memory)
+{
+    int ret, i;
+    struct sigaction act, oldact;
+    sigset_t set, oldset;
+    size_t hpagesize = fd_getpagesize(fd);
+
+    memset(&act, 0, sizeof(act));
+    act.sa_handler = &sigbus_handler;
+    act.sa_flags = 0;
+
+    ret = sigaction(SIGBUS, &act, &oldact);
+    if (ret) {
+        perror("os_mem_prealloc: failed to install signal handler");
+        exit(1);
+    }
+
+    /* unblock SIGBUS */
+    sigemptyset(&set);
+    sigaddset(&set, SIGBUS);
+    pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
+
+    if (sigsetjmp(sigjump, 1)) {
+        fprintf(stderr, "os_mem_prealloc: failed to preallocate pages\n");
+        exit(1);
+    }
+
+    /* MAP_POPULATE silently ignores failures */
+    memory = (memory + hpagesize - 1) & -hpagesize;
+    for (i = 0; i < (memory/hpagesize); i++) {
+        memset(area + (hpagesize*i), 0, 1);
+    }
+
+    ret = sigaction(SIGBUS, &oldact, NULL);
+    if (ret) {
+        perror("os_mem_prealloc: failed to reinstall signal handler");
+        exit(1);
+    }
+
+    pthread_sigmask(SIG_SETMASK, &oldset, NULL);
+}

util/oslib-win32.c

@@ -350,3 +350,22 @@ gint g_poll_fixed(GPollFD *fds, guint nfds, gint timeout)
 
     return num_completed;
 }
+
+size_t getpagesize(void)
+{
+    SYSTEM_INFO system_info;
+
+    GetSystemInfo(&system_info);
+    return system_info.dwPageSize;
+}
+
+void os_mem_prealloc(int fd, char *area, size_t memory)
+{
+    int i;
+    size_t pagesize = getpagesize();
+
+    memory = (memory + pagesize - 1) & -pagesize;
+    for (i = 0; i < memory / pagesize; i++) {
+        memset(area + pagesize * i, 0, 1);
+    }
+}