[Qemu-devel] [PATCH v3 08/32] exec: allow memory to be allocated from any kind of path

[Xiao Guangrong <guangrong.xiao@linux.intel.com>]

Currently file_ram_alloc() is designed for hugetlbfs, however, the memory
of nvdimm can come from either raw pmem device eg, /dev/pmem, or the file
locates at DAX enabled filesystem

So this patch let it work on any kind of path

Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
---
 exec.c | 55 ++++++++++++++-----------------------------------------
 1 file changed, 14 insertions(+), 41 deletions(-)

diff --git a/exec.c b/exec.c
index 7d90a52..70cb0ef 100644
--- a/exec.c
+++ b/exec.c
@@ -1154,32 +1154,6 @@ void qemu_mutex_unlock_ramlist(void)
 }
 
 #ifdef __linux__
-
-#include <sys/vfs.h>
-
-#define HUGETLBFS_MAGIC       0x958458f6
-
-static long gethugepagesize(const char *path, Error **errp)
-{
-    struct statfs fs;
-    int ret;
-
-    do {
-        ret = statfs(path, &fs);
-    } while (ret != 0 && errno == EINTR);
-
-    if (ret != 0) {
-        error_setg_errno(errp, errno, "failed to get page size of file %s",
-                         path);
-        return 0;
-    }
-
-    if (fs.f_type != HUGETLBFS_MAGIC)
-        fprintf(stderr, "Warning: path not on HugeTLBFS: %s\n", path);
-
-    return fs.f_bsize;
-}
-
 static void *file_ram_alloc(RAMBlock *block,
                             ram_addr_t memory,
                             const char *path,
@@ -1191,22 +1165,21 @@ static void *file_ram_alloc(RAMBlock *block,
     void *ptr;
     void *area = NULL;
     int fd;
-    uint64_t hpagesize;
+    uint64_t pagesize;
     uint64_t total;
-    Error *local_err = NULL;
     size_t offset;
 
-    hpagesize = gethugepagesize(path, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    pagesize = qemu_file_get_page_size(path);
+    if (!pagesize) {
+        error_setg(errp, "can't get page size for %s", path);
         goto error;
     }
-    block->mr->align = hpagesize;
+    block->mr->align = pagesize;
 
-    if (memory < hpagesize) {
+    if (memory < pagesize) {
         error_setg(errp, "memory size 0x" RAM_ADDR_FMT " must be equal to "
-                   "or larger than huge page size 0x%" PRIx64,
-                   memory, hpagesize);
+                   "or larger than page size 0x%" PRIx64,
+                   memory, pagesize);
         goto error;
     }
 
@@ -1230,15 +1203,15 @@ static void *file_ram_alloc(RAMBlock *block,
     fd = mkstemp(filename);
     if (fd < 0) {
         error_setg_errno(errp, errno,
-                         "unable to create backing store for hugepages");
+                         "unable to create backing store for path %s", path);
         g_free(filename);
         goto error;
     }
     unlink(filename);
     g_free(filename);
 
-    memory = ROUND_UP(memory, hpagesize);
-    total = memory + hpagesize;
+    memory = ROUND_UP(memory, pagesize);
+    total = memory + pagesize;
 
     /*
      * ftruncate is not supported by hugetlbfs in older
@@ -1254,12 +1227,12 @@ static void *file_ram_alloc(RAMBlock *block,
                 -1, 0);
     if (ptr == MAP_FAILED) {
         error_setg_errno(errp, errno,
-                         "unable to allocate memory range for hugepages");
+                         "unable to allocate memory range for path %s", path);
         close(fd);
         goto error;
     }
 
-    offset = QEMU_ALIGN_UP((uintptr_t)ptr, hpagesize) - (uintptr_t)ptr;
+    offset = QEMU_ALIGN_UP((uintptr_t)ptr, pagesize) - (uintptr_t)ptr;
 
     area = mmap(ptr + offset, memory, PROT_READ | PROT_WRITE,
                 (block->flags & RAM_SHARED ? MAP_SHARED : MAP_PRIVATE) |
@@ -1267,7 +1240,7 @@ static void *file_ram_alloc(RAMBlock *block,
                 fd, 0);
     if (area == MAP_FAILED) {
         error_setg_errno(errp, errno,
-                         "unable to map backing store for hugepages");
+                         "unable to map backing store for path %s", path);
         munmap(ptr, total);
         close(fd);
         goto error;
-- 
1.8.3.1